BIOENERGYTRAINING
Modular Course Series
BIOEN3
Water Resources: Issues & Opportunities in Bioenergy Generation
Bioenergy & Sustainability Course Series
fyi.uwex.edu/biotrainingcenter
Water Resources:
Issues & Opportunities in
Bioenergy Generation
BIOEN3
March 2012
Module Guide
BIOEN 3
Authors:
Tom Franti (lead) - Extension Specialist., Water Issues related to Bioenergy, University of Nebraska-Lincoln
Bob Broz - Assistant Professor Extension Agricultural Engineering, University of Missouri Extension
Eleanor Burkett - Extension Educator, University of Minnesota Extension
Roberta Dow - Groundwater, Water Quality Specialist, Michigan State University Extension
Erica Jobman - University of Nebraska-Lincoln
Chele Norrie - University of Nebraska-Lincoln
BIOEN3 Curriculum Development Team:
Tom Franti (lead) - Extension Specialist., Water Issues related to Bioenergy, University of Nebraska-Lincoln
Bob Broz - Assistant Professor Extension Agricultural Engineering, University of Missouri Extension
Eleanor Burkett - Extesnion Educator, University of Minnesota Extension
Rick Cruse - Professor, Agronomy and Iowa Water Center, Iowa State University
Roberta Dow - Groundwater, Water Quality Specialist, Michigan State University Extension
With Contributions From:
John Quinn - University of Nebraska-Lincoln
Liz Sarpo - University of Nebraska-Lincoln
Charles Shapiro - University of Nebraska-Lincoln
Peer Review:
Ken Cassman - University of Nebraska-Lincoln, Rick Cruse - Iowa State University, Dan Downing - University of Missouri, Patricio
Grassini - University of Nebraska-Lincoln, John Hay - University of Nebraska-Lincoln, Erica Jobman - University of Nebraska-Lincoln,
Charlie Wortmann - University of Nebraska-Lincoln
This guide is also available as an online learning module at:
http://blogs.extension.org/bioen3/
Additional modules on Energy independence, Bioenergy Generation,
and Environmental Sustainability are available online at: http://fyi.uwex.edu/biotrainingcenter/
This material is based upon work supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, under
Agreement No. WISN-2007-03790. Project Title: "Energy Independence, Bioenergy Generation and Environmental Sustainability: The
Role of a 21st Century Engaged University." Any opinions, findings, conclusions, or recommendations expressed in this publication are
those of the authors and do not necessarily reflect the view of the U.S. Department of Agriculture.
Water Resources:
Issues & Opportunities in
Bioenergy Generation
BIOEN3
Table of Contents
Summary:
3
Learning Objectives:
3
Unit 3.1: Introduction 5
Background and Guiding Questions
5
Anticipated Impacts of Bioenergy Crop Production on Water Resources
6
The Water Cycle
6
Introduction to Ecological Intensification
13
Introduction to Water Use in Ethanol Production
13
Conclusions
14
Self-test Questions - Unit 3.1
14
Unit 3.2: Watershed Level Impacts
17
Background and Guiding Questions
17
Watershed Impacts from Bioenergy
18
Biofuel Development Impacts on Water Quality
22
Landscape Conversion to Bioenergy Crops
24
Ecological Intensification
27
Conclusions
28
Self-test Questions - Unit 3.2
29
Unit 3.3: Water Use in Bioenergy Production
33
Background and Guiding Questions
33
Water Use in Ethanol Production
34
Crop Growth Water Use in Ethanol Production
38
Conclusions
43
Self-test Questions - Unit 3.3
43
Unit 3.4: Policy Options & Implications
46
Background and Guiding Questions
46
Agriculture-based Biofuels Policy
47
Biomass Crop Assistance Program (BCAP)
49
Conclusions
51
Self-test Questions - Unit 3.4
51
Bioenergy & Sustainability
1
Water Resources:
Issues & Opportunities in
Bioenergy Generation
References
BIOEN3
52
Project Collaborators
58
Curriculum Development Team and author affiliations:
58
Bioenergy & Sustainability
2
Water Resources:
Issues & Opportunities in
Bioenergy Generation
BIOEN3
Summary:
This module addresses anticipated impacts on water quality and quantity from bioenergy crop production
and processing. Topics addressed include concerns with landscape conversion (from CRP or fallow land to
intensive crop production), downstream impairment of water bodies, best management practices for bioenergy crop production, and water conservation in ethanol processing.
Learning Objectives:
1. Discuss water quality and quantity issues associated with bioenergy crop production.
2. Determine BMPs (Best Management Practices) for converting CRP (Conservation Reserve Program) and
other marginal lands to bioenergy crop production, accounting for regional variation
3. Identify water conservation strategies for the production of bioenergy crops
4. Understand ecological intensification in the context of landscape conversion and bioenergy crop production
Acronyms used in Module 3
• BCAP: Biomass Crop Assistance Program
• BOD: Biochemical Oxygen Demand
• CCC: Commodity Credit Corporation
• CRP: Conservation Reserve Program
• E10: 10 percent ethanol to gasoline blend
• E15: 15 percent ethanol to gasoline blend
• EI: Ecological Intensification
• EISA: Energy Independence and Security Act
• EPA: United States Environmental Protection Agency
• eWe: Embodied water
• FSA: Farm Service Agency
• Mgpy : million gallons per year
• RFS: Renewable Fuel Standard
• RCN: runoff curve numbers
• TCW: total consumptive water
• USDA: United States Department of Agriculture
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Water Resources:
Issues & Opportunities in
Bioenergy Generation
BIOEN3
• Wir: Irrigation water
• Wp: processing water
• ZLD: Zero Liquid Discharge
Bioenergy & Sustainability
4
Water Resources:
Issues & Opportunities in
Bioenergy Generation
BIOEN3
Unit 3.1: Introduction
Background and Guiding Questions
This unit presents an overview of the impacts of bioenergy production on water resources. Production of
bioenergy feedstocks takes place on the landscape, within watersheds. Knowledge of the water cycle and
how it functions in a watershed is important to understanding bioenergy production impacts on water resources. Increasing bioenergy production may require increased row crop production through Ecological Intensification of cropping systems. Water is needed at various rates and times throughout the bioenergy production cycle, from crop growth to feedstock processing into biofuel. Water use and its impacts on the many
aspects of the water cycle need to be part of the decision making process for biofuels crop selection and
production.
This unit will provide an introduction to these topics. Several topics will be further explored in later units. You
should have an introductory understanding of water and bioenergy issues after completing this unit.
Guiding Questions
• What are the primary water resource concerns of bioenergy production?
• What percent of precipitation returns to the atmosphere as evapo-transpiration?
• What are the goals of Ecological Intensification of cropping systems?
• What are the challenges facing the bioenergy feedstock production industry that can impact water resources
Bioenergy & Sustainability
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Anticipated Impacts of Bioenergy Crop Production on Water Resources
Growing and processing feedstocks for bioenergy production in the North Central Region will have major
economic and environmental impacts. These impacts will be most immediate from continued and increased
corn-grain ethanol production. Bioethanol production has increased ten-fold in the last 20 years. In 2010, an
estimated 13 billion gallons of ethanol was produced in the United States, with the North Central states leading production. Demand for ethanol may become greater, as the EPA recently certified the use of E15 gasoline for a portion of the U.S. light duty fleet, and may expand this to older model vehicles in the future. The
production of corn, its processing into ethanol, and the potential for expansion into production and processing of cellulosic feedstocks, will have impacts on agricultural landscapes and water resources.
Protection of water quality and quantity are both concerns when feedstock production increases to meet
bioenergy demands. Producing feedstocks with irrigation will increase pressure on water availability. Ethanol
processing plants use considerable water, and while modern plants are increasing efficiencies significantly,
there is still the potential for strains on local water supplies. Finally, the potential for expansion ontomarginal
or sensitive areas; for example, former Conservation Reserve Program (CRP) land that is highly erodible, or
marginally productive farmland that requires greater chemical inputs or wetland areas, will increase the risk of
significant nonpoint source pollution. Managing the production of bioenergy feedstocks, while protecting water and soil resources, will be the key to a sustainable bioenergy system.
Challenges facing the bioenergy feedstock production industry include: 1) minimizing landscape-level impacts of returning CRP land to crop production; 2) optimizing production on existing land to avoid expanding
crop production to sensitive land; 3) using water resources in a sustainable manner; 4) understanding and
reacting appropriately to bioenergy policy changes; and 5) producing, processing, and transporting feedstock in an efficient manner, while keeping releases of greenhouse gas emissions at a minimum.
Many of these challenges have a direct link to the quality and quantity of our water resources. Water quality
and quantity considerations in bioenergy crop production include the water use of the biofuel crops, the site
characteristics, infiltration and runoff potential, the water availability at the planting site, any changes caused
by switching from the current land use to a bioenergy crop and the processing of that crop. Water use for
agricultural production and processing, as well as the impacts changing to a bioenergy crop will have on
other parts of the ecosystem, must be considered. Methods to minimize negative water cycle impacts and
promote agricultural sustainability should be part of bioenergy planning.
The Water Cycle
The Earth is called the blue planet because water covers 70 percent of Earth's surface. The oceans contain
97.5 percent of Earth's water; land holds 2.4 percent and the atmosphere holds less than .001 percent. The
amount of water available on the earth has remained constant over time, with the same water used over and
over. Water can be lost from an area, but it is not lost from the Earth; it has simply moved. The water cycle,
also known as the hydrologic cycle, describes the movement of water on, in and above the surface of the
Earth. Figure 1.1 shows components of the water cycle. Water is an essential resource. The abundance or
Bioenergy & Sustainability
6
scarcity of water in any given location affects the quantity and quality of life since water is critical for its existence.
While the Earth’s overall water budget doesn’t change, the form water takes (water vapor, liquid or solid) and
the location of available water may change. The annual precipitation rate for Earth is over 30 times greater
than the atmosphere’s capacity to hold it. For example, huge amounts of water evaporated from oceans may
fall onto land as rain or snow, which can re-enter the ocean system through runoff carried in streams and
rivers. While water in its various forms may be in flux, the overall amount of water on Earth (or water budget)
remains the same.
The balance of the water budget is determined by the distribution of the water [1]. Water income is a gain of
water from precipitation to surface and ground water sources. Water losses occur through evaporation and
transpiration. Water incomes and losses are influenced by soil characteristics, topography of land, lake basins and river systems (how the watershed functions), seasons and climate.
Water is stored in the form of ice in glaciers or as liquid in groundwater, lakes and oceans. Current discussions in the scientific community are concerned about the losses of water in glaciers and gains of liquid water causing flooding rivers and increased ocean levels that may affect landforms and coastal communities
worldwide. There is also concern about record-breaking precipitation rates causing flooding, while other areas may experience increased drought. Although high volume rain events may cause flooding, the water table (top of the unconfined aquifer) may still remain low because of storm water runoff to surface waters (rivers, lakes and oceans) without significant infiltration or groundwater recharge. The water cycle as we know it
is changing and difficult to predict.
Public water uses can impact an aquifer. Though the Great Lakes are the largest freshwater system on Earth,
a new basin-wide water availability assessment by the U.S. Geological Survey states that the basin has the
potential for local shortages. For example, groundwater pumping has had relatively little effect on water in the
basin as a whole; however, pumping in the Chicago and Milwaukee areas has caused local groundwater
drawdown of as much as 1,000 feet. Moreover, if pumping were to increase as anticipated in the region, water levels in these areas are estimated to decline an additional 100 feet by 2040 [3].
Irrigation use also may lower the water table. One example of water table decline is in large portions of the
Ogallala aquifer, which extends from Texas to South Dakota. Some areas of this aquifer have experienced
water table decline by over 40 feet [2].
Water Cycle Processes
Movement of water in the water cycle consists of several processes: precipitation, condensation, infiltration,
runoff, evaporation, transpiration and groundwater discharge to the surface.
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Condensation and Precipitation - Condensation changes water vapor to liquid water. Water vapor in the
air will condense on nuclei, such as smoke or salt particles, when the temperature decreases or pressure
changes. Cooling in the atmosphere occurs because atmospheric pressure lessens as you go higher. Lower
pressure results in the water molecules moving farther apart and thus cooling.
Precipitation moves condensed water toward
the Earth’s surface. Water may fall as rain,
snow, sleet or hail. Water vapor spends an
average of 8.9 days in the atmosphere before
it condenses on atmospheric particulates
(such as salt nuclei or dust particles) and falls
as precipitation, or it may cool and condense
on surfaces and form dew or frost [4].
About 40 billion gallons of water move in the
lower 5 miles of atmosphere over the contiguous United States every day [5]. Around 10%
of this water comes down as precipitation
[6,7]. Most of this precipitation (67%) returns
to the atmosphere as evapotranspiration.
Figure 1.1. The water cycle involves movement of
water from land, water bodies and organisms to the
atmosphere through various processes. Image
credit: Institute of Water Research / Center for Remote Sensing, Michigan State University.
Twenty-eight percent flows into surface water
and then into the Atlantic or Pacific Oceans or into Canada or Mexico. Two percent infiltrates into groundwater, and then outflows to surface water where it flows into the oceans. Two percent is consumed by animals,
plants, people or industrial use [7].
Evaporation and Transpiration - Evaporation occurs as water changes from a liquid to the gaseous state
and goes into the atmosphere from the land, lakes, rivers and oceans. Water on surfaces such as roads,
parking lots and rooftops can often be seen evaporating as steam coming off of hot surfaces.
Various factors affect evaporation. High air pressure reduces evaporation from the Earth’s surface, but as the
air temperature increases, so does evaporation. In addition, evaporation will increase with the surface temperature of water or soil at the interface with the air. The amount of air humidity also affects evaporation;
greater humidity decreases evaporation. Yet another factor is the size of the air-water surface interface.
Greater evaporation occurs within a larger area since there will be greater airflow across the surface, which
will increase evaporation by stirring up heated surface water molecules. Water currents will also affect evaporation. If the surface temperature is not cooled by currents, it can remain at the level for continued evaporation. Water depth also affects evaporation since shallow water will warm quicker and have less cold water
being brought to the surface by convection currents than will a deeper body of water. Since shallow water
warms faster, it will experience more evaporation. Likewise, bare soil will warm faster and lose more moisture
through evaporation than will covered or planted soil.
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The amount of water in the soil will influence soil temperature. The closer the water table is to the surface,
the more upward movement of moisture and the cooler the soil. Evaporative cooling as liquid water transforms to gas, will cause further soil cooling. Thus, moister soils will be cooler and have less evaporation.
Soil texture affects upward moisture movement and air movement at the surface. Evaporation from soil is
divided into stages. The first stage shows highest evaporation in coarser soil, but the second stage shows
evaporation through soil conduction or diffusion of moisture. Studies using different soil types show evaporation in the first stage as being the quickest from sandy soil and the slowest from clay soils. The first stage is
controlled by atmospheric conditions, such as relative humidity, temperature and wind velocity. Clay soil conducts more, and thus has greater second stage evaporation; however, the overall loss is still greatest from
the sandy soil [8].
Plant cover can also influence evaporation. A dense plant canopy, such as a forest, provides shade and
cooler soils than does a row crop, where gaps in the crop canopy exposing bare soil will be present for some
period of time. Forest leaf litter or crop residues keep the soil cooler and disrupt the airflow over the soil, decreasing evaporation. Thus, the type of crop and crop management can influence the soil’s evaporative
moisture loss.
Water is also lost by transpiration, the release of water vapor from plant parts, especially the leaves via stomates. Transpiration also cools plants and enables flow of nutrients and water from roots to shoots. The rate
of transpiration is directly related to the evaporation of water molecules from plant surface, especially from
the surface openings, or stoma, on leaves. When considering the water cycle, and because of their similar
processes, transpiration is coupled with evaporation and described as evapotranspiration.
Evapotranspiration (water lost through evaporation and transpiration) is driven by solar energy, which is affected by the season, latitude, cloud cover and the time of day. Evapotranspiration is affected by the amount
of available moisture in the soil, humidity, wind speed, plant type, plant density, root depth and reflective
land-surface characteristics. Except for precipitation, evapotranspiration is considered the most important
factor in the hydrologic cycle.
The U.S. Geological Survey report on evapotranspiration and drought indicates that 40 percent of the annual
average precipitation in the northeast and northwest U.S. is lost in evapotranspiration, while 100 percent is
lost in the Southwest [7].
Evapotranspiration from vegetation, such as corn and soybeans, is measured by comparison to evaporation
from a standard-sized open pan kept full of water (Table 1.1). By this pan method, various crops or canopy
covers can be compared to one another based on their relation to the pan-evaporation rate [9].
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9
Table 1.1. Comparison of two crops at emergence and full cover as % water evaporation from a
pan.
Crop
Corn
Soybeans
Emergent Plant
(% pan evaporation)
Full Cover
(% pan evaporation)
30%
83% (at tassel)
20%
110% (70 days)
Infiltration and Runoff - Precipitation that doesn’t evaporate or run off quickly has time to infiltrate. Water
that moistens the soil but does not infiltrate into the groundwater may return to the atmosphere by evaporation and transpiration. Coarse soils allow for greater infiltration while fine soils, such as silts and clays, increase runoff. Impervious surfaces, such as roads, buildings, driveways and parking lots, create runoff since
water accumulates but cannot infiltrate. Deep infiltration can store water for centuries. Lakes and streams
may either be recharged by groundwater or lose water to groundwater. Groundwater discharging to the surface may be experienced as cold water inflow to streams, swamps, lakes or other surface water.
The soil surface plays a major role in infiltration. Infiltration and runoff rates are affected by soil texture, structural stability, organic content, the kind and amount of swelling clays, soil depth and the presence of impervious soil layers [10]. Soil management and land use in turn affect the infiltration capacity of the native soil.
Plants break the impact of rain, slow the water movement and allow longer residence time so infiltration can
occur. Mulches, leaf litter, and plant stubble: all can slow the water movement and allow for greater infiltration. Soil channels created by worms, wildlife, such as gophers, acids on limestone bedrock and decayed
roots allow water to infiltrate more rapidly. Infiltration is reduced by 70-80 percent or more in urban areas with
buildings and pavement, compared to native woodland and prairie watersheds.
Rainwater or snowmelt that moves over the land rather than entering the ground by infiltration is called runoff. If precipitation or snow melt exceeds the infiltration rate, water will accumulate on the surface and run off.
Steep slopes encourage runoff and limit infiltration. In areas where rainfall occurs at very high rates, groundwater increases may not occur since the ground has little time to absorb the water into the subsoil and
groundwater. While there may be more flooding occurring on the Earth’s surface because of high volume rain
events, the water table in those areas may remain low because of storm water flow away from the
area.Infiltration varies by soil type, organic matter content, vegetative cover, and land use Please refer to Table 1.2) for a comparison of runoff rates for different surfaces and soils.
Bioenergy crops that will provide for greater infiltration include poplar and willow, especially if they are in
mixed stands. Miscanthus, switchgrass and alfalfa as perennial crops will behave more like pasture crops in
restricting runoff and encouraging infiltration. Corn, cotton, soybeans, mustard family members (canola, mustard, oil seed radish, etc.), sugar cane and other row crops will provide for less infiltration, particularly prior to
canopy closure, and greater potential runoff during crop establishment and after harvest.
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Table 1.2. Relative infiltration and runoff rates of different soils and sites to other soils and sites
(10) .
Infiltration Rates
Greatest
Lowest
High Organic Residue
>
Medium Organic Residue
Sandy Soil
Forest
>
Pasture
>
>
Loam
Crop Land
>
>
Silty
>
>
Bare Earth
Low Organic Residue
Clay Soil
>
Buildings
>
Pavement
Runoff Rates
Greatest
Least
Low Organic Residue
>
Medium Organic Residue
Clay
Pavement
>
Buildings
>
>
Silty Soil
Bare Earth
>
>
>
High Organic Residue
Loam
Crop Land
>
Pasture
>
Forest
Water Demands and Biofuel Production
Biomass Crop Production - The demand for water is increasing in many regions. Water consumption for
human use and food production may conflict with water needs for bioenergy crops. Increased demand for
fresh water may affect ecosystem hydrology, resulting in groundwater depletion, wetland degradation, decreased stream flows, lake level decline and/or water source fragmentation. Wise allocation of this limited
resource is critical.
Rainfall meets most of the water demand for crop production (80 percent). The remaining 20 percent comes
from irrigation with surface and groundwater. Water quantity demands for growing annual bioenergy crops
are similar to those of other farm crops. However, the competition for water resources is a concern, especially where water is scarce. The most obvious water quantity issues are in areas where irrigation is required
for crop production. Changes in evapotranspiration with changes in land use can also affect ecosystems.
Different crop types have different evapotranspiration rates. Crop changes leading to resource changes may
be difficult to assess and be unexpected and irreversible [11].
Agricultural regions need to be considered when thinking about selecting a crop and considering the crop
water demands. Water use by corn, for instance, is greater than that of soybeans or cotton in the Pacific and
Mountain regions, less than those crops in the Northern and Southern Plains regions, and about the same in
the North Central and Eastern regions [12].
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In most of the Corn Belt, corn for ethanol is grown under rain-fed conditions, but in the Great Plains a reliance on irrigation to grow corn makes the water use for biofuel production much greater. Regional differences are significant.
Native perennial crops used for cellulosic biomass (such as switchgrass) require the vegetation to be removed, but stubble and roots are left intact, which helps hold soil in place and reduce the amount of erosion.
Currently, perennial biomass crops are expected to require less fertilization and pesticide applications than
most row crops, reducing the chemical pollutant threats on the water source. Greater desired yields from
cellulosic crops may require added nutrients, monocropping and the use of more pesticides. In theory, native
perennial crops should create a positive effect on water quality, but little research has been done on largescale operations, so conclusions with reference to inputs and impacts are preliminary.
A wide variety of crops, both annual and perennial, have been used or proposed for biofuels, ranging from
woody (willow and poplar trees) to herbaceous (Miscanthus, switchgrass, corn, sorghum, sugar cane, alfalfa,
soybeans, sunflowers and crucifers [mustard, rape, oil seed radish]) [13]. Table 1.3 shows the ethanol production, biomass and land area needs for several bioenergy crops. Miscanthus outperforms corn and
switchgrass, as shown in this Midwest data [14].
Table 1.3. Comparison of biomass production, potential ethanol production and land area needed
for different potential bioenergy systems to reach the 35 billion gallon U.S. renewable fuel goal.
Feedstock
Corn grain (1)
Corn stover (2)
Corn total
Switchgrass
Miscanthus
Production Area Portion of 2006
for 35 bilion gal
harvested US
of ethanol
cropland
(million acres)
(%)
Biomass
(Tons/acre)
Ethnol
(gal/acre)
4.5
456
12.6
24
3.3
300
19.1
37
7.8
756
7.6
15
4.6
421
13.6
26
13.2
1198
4.8
9.3
Side-by-side comparisons of switchgrass and Miscanthus indicated that Miscanthus has double the yield of
switchgrass. Leaf level photosynthesis was 33 percent greater in Miscanthus than switchgrass. However,
transpiration was greater in the Miscanthus, which averaged 25 percent greater stomatal conductance (resulting in greater evapotranspiration [15]. Consequently, it appears greater biomass production comes at a
water cost.
Biofuel Production - The current water requirements for biofuel production are 70–400 times greater than
that used to produce other types of energy, such as fossil fuels and wind and solar energy [16]. Biofuel demands on water resources are modest when compared to feed crops. Water quality impacts from biomass
production are similar to that of conventional food crop production. Processing biomass to biofuels has poBioenergy & Sustainability
12
tentially negative implications in the form of chemical and thermal pollution via effluent release into water resources. Also, the quantity of water needed to refine biomass into biofuels may cause high impacts to local
aquifers. The water a processing facility uses to produce 100 million gallons of ethanol could otherwise supply drinking water to a community of 5,000 [17].
The ethanol distillation process, if not well managed, could be a source of surface water contamination. Salt
residue is produced in the cooling towers and is blown out in a discharge process. These salts, if added to
the waste stream, may end up as pollution in fresh waters. Also, water loss during distillation may be significant as water is released through steam in the cooling process and through evaporation during dehydration
[18].
When wastewater from processing plants is used for irrigation, it can also cause problems. The biological
activity, also known as Biochemical Oxygen Demand (BOD), associated with disposal of untreated or minimally treated wastewater with a high organic content creates anaerobic conditions in the soil. This causes a
release of the naturally occurring iron, manganese and arsenic that might be adsorbed onto soil particles that
are then altered into a form that is soluble in groundwater. Levels above the aesthetic and drinking water
standards may then be found in the groundwater [19].
Powerpoint:
Matching narrative (above text): The Water Cycle. (citation) Available at:
http://fyi.uwex.edu/biotrainingcenter/files/2011/08/BIOEN-3_PPwatercycle.pptx
Introduction to Ecological Intensification
Ecological Intensification (EI) is the state-of-the-art management of crop production focused on increasing
yield per unit of land. EI seeks to approach the attainable yield of farming systems; ideally, yields within 75-85
percent of their physiological maximum for a given soil and climate. Yield increases are fundamental in feeding a rapidly expanding world population, and meeting increasing biofuel demands. As a result of yield increases from EI, the need to break-out new land for grain production will be reduced. The system promotes
less use of marginal and erodible land for crop production, leaving these areas in restored or native conditions. This means more land is available for wildlife habitat, recreation and other purposes. As a consequence of projected population growth, non-agricultural land uses will be in greater demand. Another impact
of EI is increased carbon sequestration; which is achieved because of the greater residue biomass that accompanies higher yields. Additional crop residue from this increased production can also provide environmental benefits such as reduced water, sediment, nutrient runoff, and reduced wind erosion—ultimately improving water and air quality [19]. For more on Ecological Intensification, see BIOEN3, Unit 2.
Introduction to Water Use in Ethanol Production
Water use in ethanol production facilities is viewed in two ways: 1) the total facility water use and impact on
local water supply, and 2) the water used per gallon of ethanol produced. Total facility water use and impact
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on local water resources depends on the size of the processing facility and how efficient it is in water used
per gallon of ethanol produced. So, in fact, these two views are related.
If a facility is drawing water from a ground or surface water source then it may have a significant impact on
local water supply conditions. Aquifer drawdown may affect neighboring water users. Ethanol production
facilities can use significant quantities of water, and for this reason the industry, as it has developed, has emphasized water reuse and recycling. The Zero Liquid Discharge concept focuses on reducing consumptive
use of water to a minimum. Co-location of ethanol facilities to share water with other industrial users is an
additional efficient water practice to reduce impact on aquifers and water supplies.
In the production life cycle of corn-grain ethanol, water for feedstock growth and processing into ethanol,
use the greatest amount of water; and water to grow the feedstock dominates consumptive water use.
However, the monetary cost to provide this water, and ultimate “water cost” paid, including redirecting water
from alternative uses, depends on whether crops are grown with irrigation or without, and how water is
treated in ethanol processing facilities. There are vast differences regionally in how water is used in bioenergy
production. For more on water use in ethanol production, see BIOEN3, Unit 3.
Conclusions
The production and processing of feedstocks for bioenergy will have impacts on water resources. The productive use of water for bioenergy takes place within the confines of the water cycle. Careful management of
crop water and production facility water use will be needed to ensure sustainable bioenergy production.
Self-test Questions - Unit 3.1
1.
Which bioenergy source will have the greatest impact on water resources in the North Central Region in the near
future?
a. soybean biodiesel
b. cellulosic-based ethanol from switchgrass
c. corn-grain ethanol
d. pelletized biomass from cellulosic feedstocks
e. hybrid poplars
2.
Which of the following is a potential threat to water resources sustainability in the North Central Region?
a. increased bioenergy feedstock production on irrigated land
b. inefficient bioenergy processing facilities
c. production of annual bioenergy crops on former CRP land
d. all of the above
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3.
The Earth is known as the Blue Planet because 70 percent of its surface is covered with water; what is the percent
of water available on land?
a. 30%
b. 1.5%
c. 2.4%
d. 10%
4.
Which of the following are not processes in the Water Cycle?
a. condensation and precipitation
b. production and cultivation
c. evaporation and transpiration
d. runoff and infiltration
5.
Which of the following describes water that is available for evapotranspiration?
a. water accumulated in clouds
b. runoff water from rainfall
c. water that evaporates from ponds
d. water held as soil moisture
6.
Which bioenergy crops are expected to provide for the greatest infiltration?
a. cultivated corn and soybeans
b. poplar and willow
c. miscanthus and switchgrass
d. all the above will be the same
7.
Which of the following is not true for native, perennial crops used in cellulosic-based bioenergy production?
a. vegetation is removed at harvest, leaving roots intact to prevent soil erosion
b. expected to require less fertilization and pesticide applications than most row crops
c. research on large-scale operations shows positive impacts on water quality
d. they are more profitable to grow than row crops for bioenergy
e. both b and d
f. both c and d
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8.
Ecological Intensification is described as:
a. the concept of raising grain yields closer to their genetic potential
b. reducing environmental consequences of soil degradation
c. increasing yield on currently cultivated lands
d. preventing expansion of crop production onto marginal or sensitive lands
e. all of the above
9.
Ecological Intensification relies solely on biotechnology to achieve its desired goals
a. True
b. False
10. Consumptive use of water for corn-grain ethanol production can be characterized as:
a. dominated solely by feedstock production
b. zero liquid discharge
c. variable across the North Central Region
d. consistent in all production facilities, since corn is corn
1.
Answer: C. The North Central Region leads the nation in total corn-grain ethanol production.
2.
Answer: D. All actions could threaten water quality or quantity
3.
Answer: C. 2.4%
4.
Answer: B. production and cultivation
5.
Answer: D. water held as soil moisture
6.
Answer: B. Mixed stands of trees should have the greatest infiltration rate.
7.
Answer: F. Little large-scale research has been done and profit is unknown
8.
Answer: E. All of the above.
9.
Answer: B. False. Biotechnology is an important tool, but management and other appropriate technologies
are needed.
10. Answer: C. Consumptive use varies with irrigation practices, facility efficiency and other factors.
Bioenergy & Sustainability
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Water Resources:
Issues & Opportunities in
Bioenergy Generation
BIOEN3
Unit 3.2: Watershed Level Impacts
Background and Guiding Questions
This unit describes the watershed, water quality, and water quantity impacts of bioenergy production. Conversion of Conservation Reserve Program (CRP) lands to biofuel feedstock production is a focus, as is Ecological Intensification of cropping systems. Watershed level impacts to water quality and quantity can be significant if large areas of a watershed are converted to feedstock production. Whether the change is positive
or negative will depend on cropping changes and management.
This unit describes these issues with a focus on corn-grain ethanol production, and provides a broad understanding of watershed impacts.
Guiding Questions
• What affect do plants have on runoff amount?
• What impact will establishing perennial bioenergy crops have on water resources?
• What BMPs are useful when growing bioenergy crops?
• What should be considered when converting from CRP to a bioenergy crop?
• What are the characteristics of Ecological Intensification?
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Watershed Impacts from Bioenergy
Figure 2.1. The major watersheds of the United States. Source:
http://media.mgbg.com/wkrg/photos/weather/watershed_US.JPG A local watershed map may be
obtained at: http://cfpub.epa.gov/surf/locate/index.cfm
Watershed Level Water Quality and Quantity Impacts
The land area in which all the water drains to the same place is called a watershed. There are major watersheds (or drainage basins), sub-watersheds and sub-sub watersheds (see figure 2.1).
How water moves in a watershed affects the water quality and quantity of the watershed. Stormwater runoff
is rainwater or snowmelt that moves over the land and empties into ditches and streams leading to rivers.
Ultimately, the bulk of runoff in the United States goes into the oceans. Agricultural farms and fields, developed urban areas and construction sites, green spaces such as parks and forests—all play a role in the
health of the watershed.
Plants slow runoff and promote infiltration. Plantings by a waterway or a ditch that leads to a body of water
help determine the amount of runoff that will occur at the site. Slope, soil type and vegetation affect the
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18
speed of runoff and amount of erosion. Non-vegetated, steep slopes with poorly permeable soils promote
extensive runoff carrying sediment. Stream sedimentation negatively affects oxygen levels, light penetration,
sites for fish egg laying, function of fish and invertebrates’ gills, fish and macroinvertebrate feeding, and cover
and aquatic plant growth. Not only may sediment clog a stream, but it also brings increased nutrients causing increased aquatic plant growth and algae. The Environmental Protection Agency identifies sediment as
the number one water pollutant.
The type of vegetation or crops in the watershed affects the amount of runoff. The Natural Resource and
Conservation Service has created runoff curve numbers (RCN) for various surface covers on unfrozen
ground. A RCN is estimated for various types of cover based on the hydrologic condition - a combination of
factors affecting infiltration and runoff: density and canopy of vegetative areas, amount of year-round cover,
amount of grass or closed-seeded legumes in rotations, percent of residue cover on land surface [good is >
20 percent cover] and degree of roughness. The RCN provides a guide to the relative amount of runoff from
various land covers, ranging from woods (forest) cover to row crops. In each case a greater RCN indicates
the potential for a greater runoff quantity. For example, a site with annual crops and no cover crop would
have greater runoff than a forest or meadow. Based on the RCN, a perennial grass field, protected from grazing and mowed would have a runoff potential as low as a good woods cover. Perennial crops, native grasses
and forest cover slow runoff, reduce the inputs of sediments and chemicals to water systems and increase
infiltration in the watershed [1].
Industrial Watershed Impacts
Industry has impacted both water quality and quantity. Factories were commonly built near waterways (lakes,
rivers or streams) for transportation ease. One of the most famous watershed impact cases occurred in Ohio
in 1969 where industrial waste and debris caused the Cuyahoga River to catch fire. The river has since been
cleaned; however, industrial waste still makes its way into some watersheds today. This can occur through
contamination of groundwater (spills, improper waste management, etc.) or through direct (point source) discharge into surface water.
Not only disposal, but also the removal of water can affect watersheds. Many different industries use water.
For example, ethanol and biodiesel plants use an average of 4 gallons of water for every gallon of fuel produced. A plant producing 100 million gallons of biofuel per year uses at least 400 million gallons of water per
year, or nearly 1.1 million gallons per day. In comparison, a poultry processing plant uses 2,500 gallons of
water per 1,000 pounds of live bird weight processed. An average plant will process 240,000 broilers, weighing 3-5 pounds each, per day and will use 2.4 million gallons of water per day [2].
Agricultural Production Watershed Impacts
Crop production requires water. Agriculture is a major user of ground and surface water in the United States,
accounting for 80 percent of the Nation's consumptive water use and over 90 percent in many Western
States [3].
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Overuse or misuse of water can lead to environmental problems and sustainability issues. Soil erosion, sedimentation, nutrient runoff and pesticide movement into the watershed are potential effects of overuse or
misuse of water. Fertilizer timing, application method and rate are factors in nutrient movement. Choice of
herbicides (the number one pesticide contaminant of water) should be based on the site characteristics and
the leaching and runoff potentials of the herbicide.
Water demand varies with crop and location. Overuse of water can impact the water table, which in turn can
impact the watershed through groundwater-fed surface waters. The type of irrigation equipment used (sprinkler vs. drip, ditch vs. center pivot, etc.), the management of irrigation (monitoring needs and uniformity), and
irrigation scheduling—all can impact water quantity and quality in the watershed. Nationally, 40 percent of the
groundwater withdrawals are for irrigation. For example, agriculture accounts for 3 percent of California’s
economic production but consumes 85 percent of groundwater withdrawal.
If irrigation uses more groundwater than is recharged the watershed as well as the aquifer will be diminished.
Irrigation practices in the Ogallala aquifer (extending from South Dakota to Texas) have drastically diminished
the aquifer by 100 ft. in some areas [4,5,6,7]. Cropping changes may lead to changes in irrigation needs.
Bioenergy cropping choices may decrease or increase the need for irrigation.
CRP and Marginal Land Conversion Impacts
Intense planting of bioenergy crops may result in removal of land from the Conservation Reserve Program
(CRP) or the use of non-cropped marginal lands. This may result in ecosystem niche loss and less desirable
land use. Marginal lands were generally not cultivated because they were poor farming sites. They may have
steep, erodible slopes, nutrient poor soils or low moisture retaining abilities. Bringing these lands into production may increase fertilizer and pesticide inputs, crop production costs and environmental risks.
Marginal lands converted to bioenergy crops may lead to lower economic productivity when compared to
previous usage. Conversion may cause increased soil erosion and sedimentation in the watershed. Increased
tillage may lead to increased runoff, which may cause greater erosion and sedimentation in the watershed.
Public drinking water reservoirs could be affected. Water storage structures may be silted or contaminated
by leaching and runoff. Increased growth of organisms because of nutrients entering public surface water
supplies add costs to municipalities required to treat the excessive contaminants. This may require more
chlorine to be used, resulting in trihalomethanes (THMs) and disinfection by-products (DBPs). These also
increase costs because they must be removed before the water can be distributed [8,9].
If the bioenergy crop requires more fertilizer, nitrites, nitrates and phosphorus contamination of water may
occur. Nitrites and nitrates are highly water-soluble. Nitrate contamination of groundwater and phosphorus
contamination of surface water are common fertilizer mismanagement problems. High phosphorus content in
surface water leads to overgrowth of plant life, which may cause loss of fishing and other recreation, as well
as production of toxins by certain algae and decreased wildlife habitat quality.
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Soil texture affects the movement of both nutrients and pesticides, with high clay soil being more prone to
runoff and sandy soil being more prone to leaching. Planting on marginal lands with low water holding capacity soil may result in increased weed competition, which may lead to greater herbicide use resulting in nonpoint source pollution from pesticides. If bioenergy crop production leads to greater pesticide usage, the
risks for groundwater and surface water contamination may increase. Pesticides vary in water solubility and
persistence in the environment. Highly soluble and persistent pesticides are high water quality risks. The
chemical characteristics of the pesticide will determine whether it will be highly leachable, or easily leave a
field in runoff. Highly leachable chemicals pose a greater risk to groundwater, while those that adhere to soil
leave a field dissolved in runoff water and pose a risk to surface water. Water contamination from runoff or
leaching is difficult and expensive to clean up.
Depending on how the land is used, bioenergy crop conversion can be positive or negative. If conservation
practices and good management strategies are used, then bioenergy crops may increase infiltration, decrease runoff and improve the watershed. This is particularly true if perennial bioenergy crops can be planted
on a large scale. Nutrient concentrations in streams in the Ozark Plateau were greater in areas with agricultural land use. Nutrient concentrations in groundwater were higher in areas with greater agricultural land use
than in forested areas. Coliform bacterial contamination of waters, however, might decrease if manure and
animal pasturage is decreased with conversion to a bioenergy crop [10]. Water quality monitoring can help
identify changes when producers begin raising bioenergy crops. Site factors, such as endangered species,
wildlife corridors, watershed recharge areas, etc., should also be considered when changing the land use of
a site.
Establishing Bioenergy Crops
Bioenergy crops can provide benefits to the soil and environment if management practices are incorporated
into the growing process and if the crop is in the right location. For example, perennial bioenergy crops, such
as switchgrass, produce deep root systems that can help increase water infiltration and soil quality. Structural
conservation practices, such as strip cropping, terraces, grass field buffers or diversion channels to slow water movement, reservoirs (depressions) to capture water and allow infiltration, and native vegetated strips
along waterways can provide a good start at soil and water conservation. In addition, management practices, such as, conservation tillage, no-till, mulching, contour farming or deep chiseling to break up a hardpan, and the use of cover crops or perennial crops should be used to complement structural practices. Producers should select appropriate practices based on the needs of the site, the landowner preference, and
the environmental sensitivity of the land.
Establishing a bioenergy crop requires assessing the site and the crop characteristics. Regional variation in
crops and bioenergy crop capabilities need to be considered. Annual crops, such as soybeans and corn, are
bioenergy crops, but are they best suited for the site? Perennial crops like switchgrass, Miscanthus and
woody plants are alternatives that may provide better production and profit, based on inputs, environmental
factors and location. Regional variations occur because of climate, rainfall, soil types, and slope. Landowner
farming attitudes also play a role.
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21
Bioenergy crops are needed. Many power plants are mixing present fuel sources with bioenergy crops. Corn
cobs for example, are used as a source of fuel in Columbia, Missouri. Some states are mandating the use of
renewal energy sources. Well-selected and managed bioenergy crops can promote wildlife habitat, increase
soil tilth, reduce pesticide use, reduce soil erosion and increase water infiltration. Understanding how and
where to establish specific bioenergy crops can increase productivity and profitability. Increased profitability,
not increased production, is one of the keys to having a successfully managed bioenergy crop that meets
soil and climate conditions and protects the watershed.
Powerpoint:
Matching narrative (above text): Watershed Impacts from Bioenergy. (citation) Available at:
http://fyi.uwex.edu/biotrainingcenter/files/2011/08/BIOEN-3_PPwatershedimpactsMATCH.pptx
Powerpoint:
Full slide set: Watershed Impacts from Bioenergy. (citation) Available at:
http://fyi.uwex.edu/biotrainingcenter/files/2011/08/BIOEN-3_PPwatershedimpactsFULL.pptx
Biofuel Development Impacts on Water Quality
Land use and management have direct impacts on water quality. Thus, it is easy to imagine the different impacts on water quality from row crop production compared to perennial grass production. This contrast illustrates the range of impacts various bioenergy crop production systems will have on water quality. Simply, the
impact of bioenergy crop production on water quality will depend on the type of crops grown and the management practices used to grow them. Much is known about the water quality impacts of some bioenergy
crops, such as corn, but little is known about the impact of other potential crops. Currently, and for the foreseeable future, corn grain ethanol will be the dominant biofuel produced in the North Central Region. If cellulosic ethanol production becomes viable, the impact on water quality may be beneficial, but may vary.
Water Quality Impacts of Expanded Corn Grain Ethanol Production
There are several potential scenarios that could unfold to meet the increased demand for corn grain ethanol.
Each of these scenarios will expand corn production in a different way, or onto different types of land, and so
will have different potential impacts on surface and ground water quality. What is certain is that expanding
corn production to more acres will increase the amount of tillage, fertilizer and pesticide use in the region.
It is likely that corn production will increase on all these fronts: expansion onto marginal land, cropping on
former CRP land, changes in rotations, and Ecological Intensification. In each case, using appropriate best
management practices to protect water quality will be essential.
Marginal Acres - Production could be expanded onto marginal land that is currently out of production because it is not economically productive. Cropping marginal lands can negatively impact both surface and
ground water quality, because each additional acre of land brought into production adds a modest amount of
Bioenergy & Sustainability
22
contaminants into water. The potential negative impact of cropping marginal land, which requires even
greater fertilizer inputs, will be proportionately greater yet.
CRP Acres - Similarly, Conservation Reserve Program (CRP) land, currently sown to perennial grass, could
be brought back into production. Much of this land is classified as highly erodible, which is the reason it was
put into CRP. Cropping CRP land could result in significant increases in soil erosion and associated transport
of nutrients and pesticides to surface water. Reversing 25 years of water quality benefits by removing land
from CRP will have severe impacts on river, lake and reservoir water quality.
There are other factors besides ethanol demand pushing the expansion of corn production onto CRP lands.
Studies in Iowa have shown a significant increase in a farmer’s willingness to plant CRP land when corn
reaches $5.00 per bushel [2]. Also, Farm Bill policy has reduced the total number of acres allowed in CRP
enrollment. These two factors, price and policy, added to ethanol demand, could create conditions where
much CRP land is converted to corn production.
See the section “Landscape Conversion to Bioenergy Crops” for management recommendations to convert
CRP to crop production.
Change in Crop Rotations - If demand is very high, or if market forces dictate, continuous corn production
could replace the rotations used today, resulting in recurring annual inputs for corn production and subsequent negative impacts on water quality. Surveys in Nebraska suggested price would be a strong motivator
for converting from a corn-soybean rotation to continuous corn. However, farmers with wheat in rotation
would be unlikely to switch to continuous corn [3].
Ecological Intensification - Another alternative to meeting corn production demand is to increase the yield
on current corn acres, without bringing new, marginal or highly erodible acres into production. Improved nutrient, water, and pest management through Ecological Intensification to increase yield, if done well, can provide increased yield without anticipated negative impacts on water quality (See the last section in this unit for
more on Ecological Intensification).
Water Quality Impacts of Cellulosic Ethanol Production
If commercial cellulosic ethanol production using perennial crops becomes viable, then maintaining more
acres in perennial grasses may result in much less impact on water quality compared to row crop production. Perennial systems have much lower losses of soil, nutrients and pesticides than do row crops, can be
integrated into landscapes to improve water quality (e.g. grass buffers, strip cropping), and can be managed
on marginal and highly erodible lands.
However, if cellulosic ethanol production using crop residues and stover becomes viable, there may be potential negative impacts to surface water quality. Removing too much crop residue can significantly increase
Bioenergy & Sustainability
23
soil erosion, with resulting losses of nutrients and pesticides. Also, some amount of returned crop residue is
needed to maintain soil organic matter content.
Although cellulosic ethanol production may have some advantages for maintaining water quality, currently no
such large-scale cellulosic bioenergy systems are in production.
Landscape Conversion to Bioenergy Crops
This section presents information on sustainable management and landscape diversity issues surrounding
utilization of biomass for bioenergy production. It includes discussion on converting CRP lands to crop production, with state-specific references provided.
Sustainable Management
There are environmental benefits and challenges associated with the utilization of biomass for energy and
other bio-based products. For example, while the responsible use of biomass for energy can help moderate
greenhouse gas (GHG) emissions, protect soil, water and air quality, and enhance wildlife habitat for targeted
species, improper practices can reduce or even put these benefits at risk. Recognizing these concerns, various strategies, generally labeled as best management practices (BMPs) or guidelines, have been developed
to mitigate negative impacts. The fact sheet, Sustainable Management for Biomass Removals: Environmental
Concerns and Mitigation Strategies, reviews environmental concerns and mitigation strategies associated
with the management and harvesting of biomass on soil productivity, water quality and quantity, and biodiversity and wildlife.
Reading:
Zamora, D. & Blinn, C. (2011) Sustainable Management for Biomass Removals: Environmental Concerns and Mitigation Strategies. Bioenergy Training Modular Course Series - BIOEN 2. Available at:
http://blogs.extension.org/bioen2/units/unit-2-3/sustainable-management/
Landscape Diversity
The fact sheet, Landscape Diversity, highlights emerging concerns about converting traditional crops to bioenergy crops. New possibilities in terms of feedstocks, such as the use of high-diversity plantings of native
tallgrass prairie species, have reinvigorated debate over diversity and productivity relationships and how well
experimental results scale up to operational levels. The choice of feedstock, species mix and landscape diversity, as well as context and configuration will likely have cascading effects on wildlife populations and ecosystem dynamics.
Reading:
Werling, B. & Landis, D. A. (2011) Landscape Diversity. Bioenergy Training Modular Course Series BIOEN 2. Available at: http://blogs.extension.org/bioen2/units/unit-2-3/landscape-diversit/
Bioenergy & Sustainability
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CRP Conversion to Row Crop Production
Land Preparation - The land condition after ten or more years in CRP will be highly variable, depending on
the vegetation present, the level of maintenance during the period, and the amount of animal activity in the
area. Visual inspection of the land by walking or from an ATV will allow assessment of the land condition.
Ideally, there will be few eroded spots, no gullies or animal burrows, and the plant stand will be uniform, with
few invasive species or little woody vegetation (shrubs or cedars). This is unlikely, however; so preparation of
the field for planting may take multiple tillage passes to correct these trouble spots. If the CRP land does not
have a lot of rodent holes and other dangers to equipment, no tillage is recommended. If the land needs leveling or smoothing, it is best to disturb it as little as possible.
The pre-planting objectives are to kill or remove the growing vegetation, which usually includes either a warm
season or cold season grass. Standing grass presents a formidable challenge to kill or remove. Timing of
land preparation will have to follow NRCS guidelines so CRP vegetation is not killed or harvested in a way
that violates the contract.
Killing Vegetation - Most research on conversion of CRP took place in the late 1990s before glyphosateresistant crops were readily available. The use of glyphosate will make a no-till CRP conversion easier, and
the lower cost of the chemical may make it more profitable than use of other land preparation strategies.
In order for glyphosate to kill grass, the grass must be actively growing. Depending on whether the prevailing
grass is a warm or cool season species, different strategies may be needed. For warm season grasses, the
ideal application time is in the summer preceding spring planting. Cool season grasses are easier to kill, and
since they grow late into the fall and start growing early in the spring, they should be controlled with glyphosate in the fall, with a second application in spring if needed.
Removing Vegetation - Research on CRP in northeast Nebraska indicated there was 5 tons of mulch per
acre in a brome CRP field. The mulch contained 110 lbs of nitrogen and 2700 lbs of carbon. The standing
grass, when harvested for hay, yielded 1.0 ton/acre. When hayed, not much of the mulch was removed. Although mowing and removing the standing grass makes for easier fieldwork, yields were only affected slightly
by the residue removal [1].
One option is to cut and hay the standing grass in mid-summer. After the grass grows back it can be
sprayed with glyphosate herbicide. The following spring a row crop can be planted. Either corn or soybeans
can be grown following CRP. Both of these crops can be planted no-till. In the past, no-till corn faced three
challenges: weeds, seed soil contact, and nitrogen requirements. With glyphosate-resistant corn, the weed
issue is not as critical
No-Till Planting Corn Following CRP - Replacing CRP grass with a healthy corn stand can be problematic. A
grass residue mulch provides a challenge to plant through, an uneven mulch will make uniform seed depth
more difficult to achieve unless the mulch is moved away. Many producers have been farming no-till for an
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25
extended period of time compared to the late 1990s, therefore many producers are more experienced in setting planters to get the seed soil contact they need. This is not the situation to experiment with no-till.
Soil Nutrients - Since little plant material was removed during CRP, soil fertility levels for non-mobile phosphorous and potassium will be similar to levels at the beginning of the CRP period. A thorough soil-sampling
program should be completed before planting the first crop. If any tillage will be done, an application of lime,
phosphorus, and potassium would be beneficial. The main challenge will be with nitrogen management. The
large amount of mulch will be high in carbon, and will take time to breakdown. In the breakdown process,
nitrogen will be immobilized for a period of time.
Research in northeast Nebraska found that at least 50 lbs more nitrogen per acre was needed to achieve the
most profitable yields for corn grown following CRP. This was because of two factors. First, the mulch on the
soil needed nitrogen to mineralize, and therefore needed extra nitrogen to support this function. In addition,
the University of Nebraska’s recommended procedure predicts nitrogen release from organic matter in the
soil. Researchers conducting the studies found that the amount of nitrogen released was less than what
would be released in fields that were in continuous row crop production. Reduced tillage may slow mineralization, but previous research could not document this, and so the nitrogen recommendations are the same
regardless of tillage used to control CRP grasses [2].
Nitrogen Application in Former CRP Planted to Corn - The method of nitrogen application also needs
to be considered. Applying a large quantity of urea-based fertilizer to the soil surface without incorporation
might lead to a large amount of ammonia volatilization. Incorporation through tillage is not recommended. An
alternative would be to use urea ammonium nitrate (UAN) fertilizer solution, and knife it in. The northeast Nebraska research found that the corn was nitrogen-deficient into midseason when the nitrogen was knifed in,
presumably because it did not move laterally in the soil, and it took awhile for the roots to reach the nitrogen
bands. It would be prudent to put selected amounts of nitrogen on with the planter, to the side of the row,
thus combining broadcast and knifed-in applications.
Benefits of Soybeans as First Post-CRP Crop - Many problems associated with planting corn following
CRP can be avoided by planting soybeans. Soybeans can be planted later in the season, which allows another spray of chemicals before the crop is up. This is less of a problem with the new GMO herbicide resistant varieties. Seed soil contact is not critical since soybeans are over-planted and soybeans compensate for
skips better than corn. Since it will have been some time since soybeans were planted in the field, it may be
wise to inoculate. If inoculated correctly, there may be no need for nitrogen applications, and that will avoid
concern about potential nitrogen losses to surface and groundwater.
Multiple Year Viewpoint - Conversion from CRP to row crops needs to be viewed over several years so
that the long term benefits of the CRP are maintained, and that farming the land is profitable.
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Fact Sheet:
Shapiro, C, Quinn, J, Franti, T, & XXXX, L. (2011) Opportunity for Direct CRP Conversion Into Organic Production. Available at:
http://blogs.extension.org/bioen3/files/2011/08/BIOEN-3_FScrporganicFINALv1.pdf
Powerpoint:
Converting CRP to Crop Production Using No-till. Available at:
http://fyi.uwex.edu/biotrainingcenter/files/2011/08/BIOEN-3_PPorganics.pdf
Resources:
CRP Conversion to Row Crop Production
CRP Conversion: Soil Fertility
Soil Testing in the North Central Region
CRP Conversion: Nebraska panhandle
CRP Conversion: Missouri
PDF
PDF
PDF
PDF
Ecological Intensification
Ecological Intensification (EI) is the concept of increasing grain yields closer to their genetic potential, while
reducing environmental consequences of soil degradation, water pollution and resource exhaustion. The goal
is to achieve yields within 80-85 percent of their physiological maximum for a given soil and climate. Achieving this will require improved agronomic management that achieves 70-80 percent nitrogen fertilizer uptake
efficiency (currently about 30-50 percent depending on crop and cropping system), water use efficiencies of
90-95 percent in irrigated systems, a large net energy ratio, and a net reduction in greenhouse gas emissions.
The goals of Ecological Intensification can be summarized as:
• Increased yield per unit of land (by producing closer to a crop’s attainable yield)
• Improved input management (through optimum use of nutrients, pesticides and water)
• Reduced environmental degration (due to less soil and chemical runoff)
• Habitat preservation (by keeping set aside, marginal lands, and native ecosystems out of production)
Because of the rising human population, demand for grain, as well as demand for biofuel, such as corn grain
ethanol and biodiesel is increasing. The goal is to provide sufficient food and fuel to meet demand, but to
also protect soil, water, and resource endowments into the future on land currently under cultivation and undeveloped land. Ecological Intensification is needed to significantly increase yield on currently cultivated
lands, to both protect soil and water resources associated with these acres, and to avoid expansion of pro-
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duction to new acres, especially on marginal land not suited for continuous crop production or natural ecosystems that provide habitat for wildlife and biodiversity [1].
Using the latest technology and best management practices, Ecological Intensification should improve soil
quality and provide a net positive energy balance for food, feed, fiber, and biofuel. Significant research and
improved crop management will be required to reach these goals. Practices such as precision agriculture,
integrated pest management, and real-time water and fertilizer management will be required in these production systems.
For additional information, visit:
http://www.ipni.net/ipniweb/portal.nsf/0/6467B7229A075DFF8525720800242553
Conclusions
Population growth and biofuel demand is driving worldwide demand for grains. The growth in average grain
yield has slowed and reached plateaus for corn, rice, and wheat in several countries that are major producers. The same pattern has been observed for irrigated corn in some of top corn-yielding counties in Nebraska. The global population continues to grow, therefore, either grain yields must increase on currently cultivated land, or additional land will be brought into production. Some land that can be brought into production, such as Conservation Reserve Program acres in the U.S., are environmentally vulnerable and best left
out of production as negative environmental consequences may result.
While biotechnology is an important tool for control of insects, disease, and weed pests, it is not likely to provide a “quantum leap” in crop yields within the next 10-20 years, which is the critical time for ensuring both
global food security and natural resource conservation. Ecological Intensification provides a framework for
integration of all appropriate technological options, including biotechnology, to achieve significant yield gains
on existing cropland. Using EI to meet food and fuel demands will help to minimize expansion of cultivated
acres, while also addressing concerns about the environmental costs of agriculture.
For more information, please visit:
• Video Link: Optimizing Resources for Higher Yields. Ken Cassman, University of Nebraska-Lincoln
http://www.ksre.ksu.edu/waterquality/2010%20Cassman.htm
• Webcast Link: Ecological Intensification – The Key to Sustainable High-yield Systems. Ken Cassman, University of Nebraska-Lincoln
http://connect.extension.iastate.edu/p67731077/?launcher=false&fcsContent=true&pbMode=normal
• Powerpoint Link: Ecological Intensification – The Key to Sustainable High-yield Systems. Ken Cassman,
University of Nebraska-Lincoln (matches with Webcast)
http://www.ksre.ksu.edu/waterquality/2010/Webinars/Cassman%20Presentation.pdf
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Fact Sheet:
(2011) Ecological Intensification of Crop Production: The Need for EI. Available at:
http://blogs.extension.org/bioen3/files/2011/08/BIOEN-3_FSecointense1FINALv1.pdf
Fact Sheet:
(2011) Ecological Intensification of Crop Production: How EI Works. Available at:
http://blogs.extension.org/bioen3/files/2011/08/BIOEN-3_FSecointense2FINALv1.pdf
Fact Sheet:
(2011) Ecological Intensification of Crop Production: Research Example. Available at:
http://blogs.extension.org/bioen3/files/2011/08/BIOEN-3_FSecointense3FINALv1.pdf
Self-test Questions - Unit 3.2
1.
A watershed is the land area from which water drains to ...
a. a lake
b. a river
c. the ocean
d. the same point
2.
Water quality impacts to watersheds include which of the following?
a. industrial waste spills
b. nonpoint source pollution
c. soil erosion and sedimentation
d. all of the above
3.
The Environmental Protection Agency identifies what as the number one water pollutant?
a. agricultural chemicals
b. agricultural animal wastes
c. sediment
d. litter
4.
Agriculture accounts for what percentage of the nation’s consumptive water use?
a. 33%
b. 59%
c. 72%
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d. 80%
5.
Marginal lands are those not cropped because of what reasons (check all that appy)?
a. they are less economically productive than currently cultivated land
b. more pesticide and nutrient use is required to gain productivity
c. there is greater potential for erosion and nutrient runoff
d. they are best suited to other uses
Bioenergy & Sustainability
30
6.
Which of the following is not likely to happen if more land is needed to grow corn for corn-grain ethanol production?
a. marginal land will be brought into production
b. land in CRP will increase
c. crop rotations will change to support bioenergy demand
d. increases in the use of fertilizers and pesticides
e. ecological intensification of crop production
7.
Converting land from CRP to crop production requires careful planning to achieve these goals (check all that apply)?
a. avoid violating CRP contracts by killing grass too early
b. provide sufficient nutrients to the crop in the first year after CRP
c. remove all grass cover so soil can be worked more easily
d. provide a long-term goal of crop productivity and soil and water protection
8.
Where possible, planting soybeans the first year after CRP has which of the following advantages.
a. can be planted later in spring, allowing for one more application of herbicide
b. seed soil contact is not critical since soybeans compensate well for skips
c. little need for nitrogen application if soybeans are inoculated well
d. easy to plant no-till
e. all of the above
9.
Which of the following in not a goal of Ecological Intensification?
a. producing grain crops nearer their genetic potential yield
b. increasing food, feed and fuel supply
c. reducing environmental impacts of cultivating marginal lands
d. avoiding use of modern technologies
e. preserving habitat
10. The need for Ecological Intensification is driven by which of the following (check all that apply).
a. the increasing global demand for grain
b. the demand for biofuels
c. the desire to protect the environment
d. All of the above
Bioenergy & Sustainability
31
1.
Answer: D. A watershed can be identified for any of these, but is defined as draining to a given point.
2.
Answer: D. All of the above.
3.
Answer: C. sediment
4.
Answer: D. 80%
5.
Answer: A.B.C.D. All of these reasons apply
6.
Answer: B. Land will likely come out of CRP to be put into corn production.
7.
Answer: A, B, D
8.
Answer: E. All of the above.
9.
Answer: D. avoiding use of modern technologies
10. Answer: D. All of the above.
Bioenergy & Sustainability
32
Water Resources:
Issues & Opportunities in
Bioenergy Generation
BIOEN3
Unit 3.3: Water Use in Bioenergy Production
Background and Guiding Questions
This unit provides information on water use in bioenergy production. Significant amounts of water are needed
to produce bioenergy. Water is used to grow crops and to process feedstocks into biofuel. The same
amount of water may be used by a crop whether it is grown with irrigation or with rainfall only. However, the
cost and impact on water resources is not the same. The amount of water used compared to that amount
consumed by processing facilities is an important distinction in understanding water use in biofuel production.
This unit will examine these issues focused primarily on corn-grain ethanol production. Water use in processing facilities and bioenergy crops will be examined.
Guiding Questions
• How has water use in ethanol processing facilities changed in the past 20 years?
• What are some steps in Zero Liquid Discharge?
• What is embedded water in ethanol?
• What are the water advantages of processing facility co-location?
• What are the water advantages to growing perennial grass and woody biomass?
Bioenergy & Sustainability
33
Water Use in Ethanol Production
Historically the nation’s lead corn producing area, the North Central Region, now leads the bioenergy industry in production of corn-based ethanol. It also leads the nation in water used for bioenergy. In 2010, the
United States produced over 13 billion gallons of ethanol, with an estimated 11.7 billion gallons produced in
the North Central Region, which encompasses the states ranging from the Dakotas to Ohio, and Michigan to
Missouri. Iowa and Nebraska were the two leading ethanol producers [1]. The widespread soil and water
resources of the Great Plains and Midwest Corn Belt are the reason for this concentration of production [2]
(Figure 3.1).
Water use in ethanol production facilities is viewed in two ways: 1) the total facility water use and impact on
local water supply, and 2) the water used per gallon of ethanol produced. Total facility water use and impact
on local water resources depends on the size of the processing facility and how efficient it is in water used
per gallon of ethanol produced. So, in fact, these two views are related.
Figure 3.1. County-level corn production and ethanol facilities operating status by 2007. The
graph illustrates the proximity of ethanol facilities to corn production (2).
If a facility is drawing water from a ground or surface water source it may have a significant impact on local
water supply. Aquifer drawdown may affect neighboring water users and there is considerable emphasis on
water reuse and recycling. The Zero Liquid Discharge concept focuses on reducing consumptive use of water to a minimum by reusing liquid water rather than discharging it. Co-location of ethanol facilities to share
water with other industrial users is another water efficient practice to reduce impact on aquifers and water
supplies.
Bioenergy & Sustainability
34
In the production life cycle of corn-grain ethanol, water for feedstock growth and processing into ethanol are
the two greatest water users; and water to grow the feedstock dominates consumptive water use. However,
the monetary cost to provide this water, and ultimate “water cost” paid, including redirecting water from alternative uses, depends on whether crops are grown with irrigation or without, and how water is treated in
ethanol processing facilities. There are vast differences regionally in how water is used.
Corn Grain Ethanol Processing
Two processes are used to convert corn to ethanol: wet milling and dry milling. Dry milling is used by over 90
percent of corn ethanol plants in the U.S. Water is used in many processing steps to convert corn to ethanol
(Figure 3.2). High quality water is needed for the success of biological processes. Cooling water is needed to
control fermenter temperatures and in distillation. Typically, a 50 million gallon a year facility will use 500 gallons per minute of water [3]. However, much of this water is treated and reused or recycled. Consumptive
water use is from evaporation during cooling and water treatment. This water lost from the plant cannot be
recycled; however, it is a very small fraction of the total water used (Table 3.1).
For more information on ethanol wet and dry milling processes, please visit:
http://www.ethanolrfa.org/pages/how-ethanol-is-made
Table 3.1 Ethanol Plant Water Use: These survey results are from 150 dry mill ethanol plants operating during the 2008 calendar year (plus plants starting up in the winter of 2008/2009) (5).
Gallons H20 per gallon Ethanol
Average
Standard Deviation
Number of Data Points
Bioenergy & Sustainability
Fresh Water Use
Water Discharge
2.72
0.46
2.69
0.43
0.88
0.63
48
55
35
Relatively Speaking
How much water does an ethanol plant
use?
Let’s consider a 100 Million gallon per
(MGY) year ethanol facility, that uses an
average of 4 gallons of water per gal of
ethanol.
Figure 3.2 Breakdown of typical water use or wa
ter consumption in dry mill ethanol production.
Much of this water is reused or recycled, so that
total consumptive use of very small. DDGS is
Dried Distillers Grains with Solubles, the solids
left over after processing ground corn to ethanol
[4].Water Use In Ethanol Facilities
Water Use in Ethanol Facilities
Current water use data in processing facilities is generally not public information. Most industry studies show
that the amount of water used to produce one gallon of
ethanol has been dropping since 1998. A 2005 report
from Minnesota indicated average water use per gallon
of ethanol produced dropped from 5.8 gallons in 1998,
to 4.2 gallons in 2005 [2,3]. In 2005, an estimate of 4
gallons per gallon of ethanol produced was an industry
average. However, the Renewable Fuels Association [6]
reported estimates of 3 gallons of water use per gallon
This facility will use 400,000,000 gallons of
water per year. Let’s be conservative and
assume only 50% of this water is recycled
or reused. Thus consumptive use is
200,000,000 gallons of water per year.
By comparison, one center pivot irrigation
system applying 6 inches of water over 130
acres in a year will use about 21,000,000
gallons of water. It would take only 10 pivots systems using water at this rate to
equal the annual consumptive use of our
hypothetical ethanol facility.
How Much Water Does a Corn Crop Use?
of ethanol. Mueller, 2010, [5] surveyed ethanol produc-
The corn needed to supply the 100 MGY
ers in Iowa, Minnesota, Nebraska and eastern South
ethanol facility could come from 1,538 pivot
Dakota in the fall of 2008 and winter of 2009. From
2001 to 2008, water use was down to 2.72 gallons per
gallon of ethanol produced by dry mill processing. Im-
systems, potentially using 35 billion gallons
of water (at 6 inches of application).
provements in water treatment and recycling in produc-
Relatively speaking, water needed for etha-
tion facilities over the years have cut water use (Table
nol processing is a drop in the bucket
3.2). Not all operating facilities report water use, thus
compared to that needed to grow the corn.
survey averages are not comprehensive. A current industry average (2011) is likely between 3 and 4 gallons
of water used per gallon ethanol produced. Consump-
Adapted from: Ethanol Mythbusters, F.
John Hay, Extension Educator, UNL
tive use of water is much less because of improved
reuse and recycling.
Bioenergy & Sustainability
36
Table 3.2 Water Use In Ethanol Facilities Over Time: Various sources.
Gallons H20 per gallon
Ethanol
Year
Source1
5.8
4.7
4.2
4.0
3.0
2.72
~2.0
1998
2003
2005
2006
2007
2008
2010
NREL
USDA
MN
MN
RFA
NDMS
ZLD
1 NREL=National Renewable Energy Laboratory; USDA=United States Department of Agriculture; MN=Minnesota study; RFA=Renewable Fuels Association; NDMS=National Dry Mill Corn Ethanol Survey (Mueller,
2010); ZLD=estimates with Zero Liquid Discharge
Reducing Consumptive Water Use
The major processes using water in ethanol facilities are:
1) biochemical processes for converting corn to ethanol;
2) reverse osmosis for water treatment; and 3) cooling.
Industry Reports Success with
Zero Liquid Discharge
Many technologies are used to recycle and reuse water
in the facilities to reduce the discharge or consumptive
Ethanol Producer Magazine reports indus-
use of water.
try experts who indicate that zero liquid
discharge can result in a 20 to 30 percent
The concept of Zero Liquid Discharge (ZLD) is part of the
decrease in water needs. However, each
water recycle and reuse effort in the ethanol industry.
facility requires a unique design. U.S. Wa-
Some recently constructed facilities have adopted ZLD
ter Services, who provide retrofits to water
to meet regulations, for example, in the Central Valley of
systems, has four approaches: recycling
California. ZLD must maintain high quality water com-
water using cold lime softening, evapora-
patible with biological processes. Most water demand is
tion or crystallization of the discharge
from cooling towers and boiler systems.
stream, and evaporation ponds, which
only work in the Southwest. One retrofit
Steps in ZLD include: 1) management changes, such as
described by Mike Mowbray, marketing
cold lime softening, recycle loops, and generating CO2
manager for U.S. Water Services, “re-
in the facility rather than importing it; 2) diverting cooling
duced water usage from about 3.5 gallons
tower water and reverse osmosis concentrate to the
per gallon of ethanol, to 2.8 gallons with
supply water tank, 3) and treating the supply water tank
the addition of cold lime softening. Further
as a blend tank. With ZLD only a small fraction of steam
conversion to zero liquid discharge de-
escapes the system.
creased water use at the plant to just over
Facility Co-location and Water Reuse
2 gallons of water per gallon of ethanol [7].
Locating ethanol production facilities near other industrial operations that use water is a way to reduce impacts on local aquifers and water supplies. The discharge water from one industrial facility can be reused by
Bioenergy & Sustainability
37
another, therefore reducing its draw on ground water or surface water—making the two facilities more efficient water users.
Examples of this practice include two co-locations described by POET. POET is the nation’s leading ethanol
processor. POET operates a network of 27 plants in seven states in the North Central Region, and produces
more than 1.6 billion gallons of ethanol annually. Their Portland, Indiana, facility produces 68 million gallons of
ethanol annually, and is co-located with Meshberger Berger Brothers Stone Corporation (Quarry) to share
water resources. Because the City of Portland could not supply the water needed by POET, they now receive
the water released by the quarry, and 100 percent of their manufacturing water used is this water. Only potable water needs are met from wells [8].
Another example is POET’s Caro, Michigan facility. This facility produces 53 million gallons of ethanol annually, and is located next to the Big Stone Power plant. The power plant’s cooling pond is refilled each spring
by snowmelt into Big Stone Lake. The holding pond provides 100 percent of the processing water for the
ethanol facility. All of the wastewater generated by the ethanol plant is recycled back to the cooling pond.
Furthermore, 70 percent of the steam needs in the ethanol facility are provided by excess steam generated
by the power plant [8].
These two examples indicate the benefits of co-location and water reuse. Future developments such as
these collaborations, as well as improved water efficiency and Zero Liquid Discharge, will significantly reduce
the water needed and consumptive water use by ethanol facilities.
Crop Growth Water Use in Ethanol Production
The most water intensive processes in the life cycle of corn-grain ethanol production are growing the feedstock and water used in processing corn to ethanol. Of these, water consumed to grow the crop is the
greater of the two. The consumptive use of water is water applied to a crop (by rain or irrigation) that is not
returned to a ground or surface water source. For example, in crop production water lost to evapotranspiration is considered consumptive use, while water that percolates to groundwater or returns to stream flow is
not consumptive use. To grow a corn crop with rain or irrigation may take the same amount of consumptive
water use, but providing that water by irrigation taps aquifer and surface water resources at a greater cost
than using rainwater. This cost includes the cost of moving that water to the field, as well as the opportunity
cost for other functions that water could perform (for example, industrial or municipal water supply or ecosystem services).
Agriculture accounts for about 85 percent of freshwater consumption in the United States. This includes water used to produce feedstock for biofuel. Groundwater is a primary source of irrigation in the western states
in the North Central Region. Rain-fed crop production is primarily in the eastern states of the North Central
Region, although all states rely on rain that is available.
Bioenergy & Sustainability
38
Corn grain production uses approximately 22 inches of water, which requires 12 to 20 inches of rainfall or
irrigation, during the growing season [1]. Most states in the region rely on rain as the primary water source for
corn. It is estimated that 95 percent of all corn-grain ethanol is made from corn grown with rainfall. Nebraska
and Kansas lead in the use of irrigation for corn production. There is variation across the region in sources of
water used in the ethanol life cycle. The water cost to produce ethanol varies depending on where the corn
crop is produced and processed, and whether irrigation is used to produce that crop.
Regional Differences in Water Use for Ethanol
Studies have shown the total field-to-pump water use to produce one gallon of ethanol is between 69 and
207 gallons [2, 3, 4, 5, 6]. However, this data does not take into account the wide variation across the nation
in water consumption and the source of the water in crop production. Table 3.3 is a regional comparison of
the amount of water embodied in the production of ethanol. “Embodied water” (EWe) is the irrigation water
used to produce the corn and the water used in the processing facility. Rainfall is not included. The EWe
across the North Central Region ranges from 5 gallons per gallon ethanol in Ohio, to 528 gallons per gallon
ethanol in Kansas. This variability represents the differences in rainfall amounts across the region, and the
reliance on irrigation for crop production in the more westerly states (figure 3.3).
Figure 3.3 – “Potential biomass resources available in the United States” NREL, 2005.
Bioenergy & Sustainability
39
Table 3.3. EWe and TCW4 in the ethanol producing North Central States in 2007, ranked according
to each state’s EWe. Numbers are millions of gallons, unless otherwise specified.
State
Ohio
Iowa
Illinois
Indiana
Minnesota
Wisconsin
Michigan
Missouri
North Dakota
South Dakota
Nebraska
Kansas
2007
EWe1 gal/
Ethanol
gal
Production
EWe gal/
gal Ground
Water
EWe gal/
gal Surface
Water
Wir2
Wp3
TCW5
3
5
1
0.26
2.9
11
14
1,812
6
2
0
4,567
6,538
11,105
921
11
3
0
7,236
3,324
10,560
252
17
3
1.6
3,313
909
4,222
607
19
4
0.79
9,138
2,189
11,328
282
26
7
0
6,396
1,018
7,413
155
47
8
4.2
6,652
559
7,211
155
57
15
0.53
8,231
559
8,791
133
59
8
7.4
7,436
482
7,918
5,866
96
10
15
53,834
2,100
5,736
655
502
111
21
326,321
2,366
328,686
212
528
128
11
111,450
767
112,217
1 EWe = Embedded water in ethanol
2 Wir = Irrigation water
3 Wp = Processing water
4 TCW = Total consumptive water
Local Impact
The most intensive drain on water resources for ethanol production will be in areas that rely on irrigation for
corn production, and where local aquifers cannot adequately supply processing water for facilities without
impacting other local users. Understanding these regional differences can reduce fears of across-the-board
water depletions from biofuel production. But, it also points out the challenges to sustainable water resources when producing biofuels in regions reliant on irrigation. Much has been done, but further improvements can be made in efficient use of water resources for irrigated corn production.
A recent study in Nebraska pointed out that over a large irrigated region, there was very efficient corn production, but also room for irrigation efficiency improvement. These improvements include both management
and cultural practices, like no-till farming, and more efficient irrigation methods. (see SIDEBAR)
Limited Irrigation
A strategy for saving water on a basin scale is to adopt limited, or deficit irrigation. Applying less than the full
crop water needs is called limited or deficit irrigation. In water-short regions, this practice is being
Bioenergy & Sustainability
40
encouraged as a water conservation tool. If done cor
rectly, limited irrigation can reduce water use without se-
Study Shows Corn Production Ef-
rious economic impact compared to other irrigation con-
ficient, Room for Water Efficiency
servation practices for the same amount of water sav-
Improvements
ings. Studies have shown that the last few inches of water, above what the plant can use, results in marginal
“Data on yield, irrigation, and nitrogen
yield gains, at much greater cost and water use per
fertilizer collected over 3 years (2005-
bushel.
2007) from 777 irrigated corn fields in the
Tri-Basin Natural Resources District (NRD)
Fact Sheet:
(2011) Limited Irrigation. Available at:
in central Nebraska were used to estimate
current yield gaps, irrigation water-use
http://blogs.extension.org/bioen3/
efficiency, and fertilizer N-use efficiency
files/2011/08/BIOEN-3_FSlimitedirrigation
(NUE). Irrigated corn producers in the Tri-
FINALv1.pdf
Basin NRD, on average, achieved relatively high corn yields (only 11% below
Water Use for Cellulosic Biofuel Production
yield potential ceiling) with much greater
Cellulose-based biofuels are the next generation of bio-
than average nitrogen use efficiency com-
energy products. Sources of cellulose for biofuel production include perennial grasses, forest wood residues,
short-rotation woody crops and agricultural residues. It is
assumed these feedstocks will be grown in their native
regions under rainfed conditions, with little irrigation.
Cellulosic-based ethanol production promises a significant increase in the volume of fuel ethanol that can be
produced in the United States and abroad. Considerable
research and “continued advancements in pretreatment
technology, fermentation, and collection and storage logistics,” have made the commercial production of cellulose ethanol likely, although commercial facilities have not
proven viable yet [1].
Several states, from California to Pennsylvania, South
Dakota to Florida, are currently commercializing technologies that utilize cellulose feedstocks (see Figure 3.4),
[1].
Breaking down cellulose to be converted into usable
pared with the US national average,” [7].
There remain considerable opportunities
to advance yields and inputs efficiencies
by means of pivot instead of surface irrigation. Mean three-year irrigation by surface irrigation was 15.3 inches of water
and by pivot irrigation was 9.0 inches of
water. This contrasted with a modeled
optimum irrigation (more precise timing
and amount applied with crop needs)
depth of 8.3 inches and a limited irrigation
depth of 7.0 inches. Changing from surface irrigation to pivot can bring water use
very close to the optimum amount. It was
estimated that 32% of the total annual
water volume used for irrigated corn production in the study area could be saved
by converting all surface irrigation to pivot
irrigation and adopting an optimum irrigation strategy [7].
sugars for ethanol production is a complex process.
However, the use of cellulose for ethanol production exBioenergy & Sustainability
41
pands the available resources that can be used for manufacturing ethanol. Instead of producing ethanol from
starch, typically contained in corn and grain sorghum, other materials usually regarded as waste can be
used. The cellulose of “corn stover, rice straw and wood chips or ‘energy crops’ of fast-growing trees and
grasses can aid in ethanol production,” [1]. “Besides offering an alternative energy resource, they can provide
crop diversity and both economic and environmental benefits to local agricultural communities.”
Figure 3.4 – “Current Cellulosic Ethanol Projects in America.” Visit U.S. Cellulosic Ethanol Projects
for information on the status of each project and methods of production.
Fact Sheet:
(2011) Cellulosic Bioenergy. Available at:
http://blogs.extension.org/bioen3/files/2011/08/BIOEN-3_FScelllulosicbioenergyFINALv1.pdf
Crop Advantages: Impact on Water and Environment
The leading advantage of cellulose is its abundance. Also, cellulose is not used for food and can be grown in
all parts of the North Central Region. Growing grass and woody biomass reduces soil erosion when compared to conventional commodity crop production. Biomass crops generally reduce surface runoff and nitrogen transport and provide for diverse wildlife habitat [3].
“Woody and herbaceous biomass crops are not seen as competing for land with traditional row crops, such
as corn and soybeans. Rather, they are perennial crops that can be grown on more marginal lands where
erosion is a problem, where soil stabilization is needed, or where the economic returns to the farmer's labor
Bioenergy & Sustainability
42
and capital are low. Once established, maintaining perennial biomass crops requires less input of labor or
resources compared with annual cycles of planting and harvesting of traditional row crops,” [2].
Grasses and woody biomass have a high water demand, but are generally grown relying on rainfall, without
use of irrigation. Therefore, the cost to groundwater aquifers and surface water resources is low. However, in
drought-prone areas production in dry years will be low due to lack of rainfall.
Residue Biomass
It is important to note that a significant amount of biomass is crop residue. Figure 3.4 highlights biomass distribution over the North Central United States in 2005, including agricultural residues (crop and manure),
wood residues, dedicated energy crops, and Conservation Reserve Program land (CRP).
For additional information, please view:
Fact Sheet:
(2011) Grass & Woody Biomass for Bioenergy. Available at:
http://blogs.extension.org/bioen3/files/2011/08/BIOEN-3_FSgrasswoodybiomassFINALv1.pd
f
Fact Sheet:
(2011) Corn Stover for Bioenergy. Available at:
http://blogs.extension.org/bioen3/files/2011/08/BIOEN-3_FScornstoverbiomassFINALv1.pdf
Conclusions
Water use in ethanol production includes both consumptive water use for crop growth and water used in
processing facilities. Processing facilities have dramatically reduced consumptive water use over the past 20
years. With practices like Zero Liquid Discharge, consumptive use of water in state-of-the-art ethanol facilities can be less than 1.0 gallon of water for each gallon of ethanol. Water embodied in ethanol, or any biofuel, is greatest when the feedstock is grown with irrigation.
Self-test Questions - Unit 3.3
1.
The North Central states produced how many gallons of ethanol in 2010?
a. less than 6 billion gallons
b. nearly 12 billion gallons
c. over 25 billion gallons
d. just under 53 billion gallons
2.
Which of the following processes in corn-grain ethanol dry mill processing uses the most water?
a. drying
Bioenergy & Sustainability
43
b. cooling tower
c. boiler
3.
Various surveys indicate that water use per gallon of ethanol produced has dropped from 5.8 gallons per gallon of
ethanol in 1998, to 1.75 gallons per gallon of ethanol produced in 2008.
a. True
b. False
4.
Consumptive water use in ethanol processing is defined as the following:
a. drinking water consumed by operators of the facility
b. water recycled and reused in a production facility
c. water lost to evaporation and discharge that is not returned for use
d. water withdrawn from a well
5.
Zero Liquid Discharge includes which of the following (check all that apply):
a. diverting cooling tower water to the supply water tank
b. management changes, like recycle loops
c. allowing only a small fraction of steam to escape the system
d. treating the supply water tank as a blend tank
6.
The greatest water use in the life-cycle of corn-grain ethanol is what?
a. water used in the processing facility
b. water consumed to grow the feedstock
c. water used to harvest, dry and deliver the grain
d. none of the above
7.
It is estimated that 95 percent of all corn-grain ethanol is made with corn grown with what?
a. rain water
b. irrigation water
c. a combination of irrigation and rain water
8.
Studies have shown that field-to-pump water use to produce one gallon of ethanol is what range?
a. 69 to 201 gallons of water per gallon of ethanol
b. 5 to 528 gallons of water per gallon of ethanol
c. 10,000 to 50,000 gallons of water per gallon of ethanol
d. over 100,000 gallons of water per gallon of ethanol
Bioenergy & Sustainability
44
9.
Embedded water in ethanol is greatest in what state?
a. Ohio
b. Kansas
c. Iowa
d. Nebraska
10. When cellulosic-based ethanol becomes economically viable, its production will likely be more water efficient for
what reasons (check all that apply)?
a. woody and native species will be grown in adapted climates under rainfed conditions
b. processing facilities will adopt mature water reuse and recycling technologies
c. cellulosic conversion technology does not need water
d. none of the above
1.
Answer: B. nearly 12 billion gallons
2.
Answer: B. cooling tower
3.
Answer: B. False. It varies, but estimates are around 3.0 gallons water per gallon of ethanol produced.
4.
Answer: C. Water is recycled and reused in a production facility, but some portion is lost to evaporation
and discharge; this lost portion is the consumptive use
5.
Answer: A, B, C, and D. All of these apply.
6.
Answer: B. water consumed to grow the feedstock
7.
Answer: A. rain water
8.
Answer: A. 69 to 201 gallons of water per gallon of ethanol
9.
Answer: B. Kansas
10. Answer: A and B.
Bioenergy & Sustainability
45
Water Resources:
Issues & Opportunities in
Bioenergy Generation
BIOEN3
Unit 3.4: Policy Options & Implications
Background and Guiding Questions
This unit provides an overview of federal energy and agriculture policies that drive and provide incentives for
biomass and bioenergy production. Policy is driving the industry. This unit will help in understanding policy
and how policy might change as technology and markets evolve. For more information on bioenergy policy,
see BIOEN2, Unit 1, “Federal & State Incentive Programs.”
Guiding Questions
• What is the Renewable Fuels Standard (RFS)?
• How will widespread adoption of E15 gasoline impact cellulosic ethanol production?
• What is BCAP?
Bioenergy & Sustainability
46
Agriculture-based Biofuels Policy
Alternative Fuels Legislation
For the last several decades, government incentives have influenced production of agriculture-based renewable energy. These federal policies work to stimulate alternative uses of domestic grain and oilseeds, promote national security through greater energy self-sufficiency, and encourage rural economic development.
Ethanol and biodiesel output have increased dramatically in recent years: a combined 1.4 billion gallons in
1998 escalated to over 11 billion gallons in 2009. This surge in output, virtually all in the form of cornstarch
ethanol, can be attributed to federal incentives—tax credits, renewable fuel requirements, and research and
development funding.
The appropriate level and type of federal intervention in renewable energy markets is an issue that Congress
is facing. With the expansion of corn-based ethanol and an increase in demand for grain and oilseed, farm
incomes have elevated and several rural economies have been revived. This expansion has created a spillover effect in other markets, such as land, livestock, farm input and energy. Each year, policy provisions that
assist the United States biofuels industry, including tax credits and the import tariff, “are set to expire pending
congressional action to extend them,” [1].
There are spillover impacts, such as land use change to bioenergy crops, increased water use for bioenergy
production, and market forces on the food and feed industry with competition for land and commodities.
Many land use changes and water resources impacts have been described in this curriculum. This policy
section provides a review of the main federal policy driving bioenergy development, particularly, ethanol production.
Federal Legislation Driving Ethanol
In recent years, three major bills have impacted the bioenergy industry. The Energy Policy Act of 2005, “established a Renewable Fuel Standard (RFS) that mandated minimum-use volumes of biofuels in the national
transportation fuel supply,” (Figure 4.1) [1]. A second Act, the Energy Independence and Security Act (EISA)
of 2007 expanded the RFS. Lastly, the Food, Conservation, and Energy Act of 2008 (2008 Farm Bill) extended and expanded incentives for ethanol production. The Farm Bill extended tariffs on imported ethanol
and promoted use of bio-based products. In February 2010, the Environmental Protection Agency announced new and final rules with the RFS that included mandatory reductions in life-cycle greenhouse gas
emissions for each biofuels category and, “restrictions on the type and nature of feedstocks used to produce
RFS-qualifying biofuels,” [1].
The Rise to E15
In October 2010, the United States Environmental Protection Agency (EPA) announced a waiver, raising the
allowable ethanol blend rate with gasoline for some late model vehicles to 15 percent (E15), from the previous allowable blend rate of 10 percent (E10). The waiver applies only to model year 2007 and newer cars
and light trucks. Further testing and available data on E15’s impact on engine durability and emissions are
Bioenergy & Sustainability
47
now being examined. To date, testing has shown that E15 does not harm emissions control equipment in
newer cars and light trucks. “A decision on the use of E15 in model year 2001 to 2006 vehicles will be made
after EPA receives the results of additional DOE testing,” [2]. This EPA regulation change could have a dramatic effect on ethanol production if it eventually applies to all vehicles. In other cases, such as motorcycles,
heavy-duty vehicles, or non-road engines, there is not yet enough data to support such a waiver. However,
an increase in research and testing, and subsequent waiver to E15 for more vehicle types, could increase
ethanol production significantly.
Future Expectations
Since the inception of the RFS in 2005, U.S. total biofuels production has exceeded the standard (through
2010). Under the Energy Independence and Security Act (EISA) of 2007, “the cellulosic biofuels mandate
grows quickly from 100 million gallons per year (mgpy) in 2010 to 16 billion gallons by 2022,” [1]. In the five
years following 2010, increases in biofuel production from the RFS are primarily intended to result from cellulosic biofuels rather than cornstarch ethanol (Figure 4.2). However, major uncertainty remains, with the speed
of cellulosic biofuels development. The ability or inability of the U.S. biofuels sector to expand production
capacity, to meet the ever-increasing RFS mandate, will most likely be an issue that Congress will face in the
near future.
Another issue that Congress could potentially face is the effectiveness of incentives that spur commercial
viability in cellulosic biofuels production. Early in 2010, cellulosic biofuels were being produced on a very
small, non-commercial scale in the U.S., thus making the 100 mgpy mandate for 2010 an intimidating target.
On February 3, 2010, the EPA consequently announced a reduction in the 2010 cellulosic biofuels RFS to
6.5 million gallons. “Waivers are built into EISA to accommodate shortfalls if the U.S. biofuels industry (with
imports) fails to meet the RFS,” [1]. Congress will most likely debate legislative solutions such as modifying
eligibility requirements or reducing RFS cellulosic biofuel volumes to overcome potential long-term shortfalls.
Potential Impacts
Significant consequences can be expected for food and energy markets, and for water resources, as the
RFS mandate for biofuels steadily increases and becomes binding, especially if there is significant increased
demand for corn-based ethanol. The potential conflict associated with conversion of domestic food crops to
biofuels can be related back to the short-lived commodity price spikes of mid-2008.
The EISA of 2007 and the 2008 Farm Bill redirected biofuels research and development emphasis to cellulosic biofuels, in an effort to shift biofuels policy distortions away from livestock feed and other markets, [1].
This may reduce the corn-based ethanol demand, because cellulosic biofuels have the ability to be produced
from non-food feedstocks, such as crop residues, dedicated energy crops and woody biomass. Accordingly,
a slowdown or failure in meeting the RFS goals for cellulosic biofuels production could have inadvertent consequences by increasing the demand for corn-based ethanol and the resulting environmental impact from
landscape conversion and increased water resources exploitation.
Bioenergy & Sustainability
48
Biomass Crop Assistance Program (BCAP)
The Renewable Fuel Standard (RFS) has mandated minimum volumes of biofuels in the national transportation fuel supply, of which cellulose-based fuels will be a component after 2016, and a major component by
2021. These projections imply that cellulose-based fuels will be commercially available at competitive prices.
Expectations may be lowered over time. In either case, a reliable supply of cellulosic biomass will be needed
in the future. Policy is being implemented to provide this.
The Farm Service Agency (FSA) Energy Program, the Biomass Crop Assistance Program (BCAP), works to
provide financial support to private landowners. Owners and operators of agricultural and non-industrial private forestland are eligible for assistance if their objective is to establish, produce, and deliver biomass feedstocks. Assistance from BCAP is divided into two authorized funding categories:
• Certain landowners who participate in contracts with the Commodity Credit Corporation (CCC) to generate
eligible biomass crops on contract acres within BCAP projects areas may qualify for both establishment
payments and annual payments.
• Matching payments may be obtainable for the distribution of eligible material to qualified biomass conversion facilities by eligible material owners. Qualified biomass conversion facilities produce heat, power, biobased products, or advanced biofuels from biomass feedstocks.
Program Objectives
BCAP works to support the establishment and production of crops, including woody biomass, for conversion
to bioenergy; this part of BCAP is called “establishment
of annual payments.” The program also works to assist
with the collection, harvest, storage and transportation
of eligible material for use in biomass conversion facilities; this is called “matching payments.” In response to a
presidential directive to accelerate the development of
advanced biofuels, the BCAP, as a partner to the U.S.
Department of Agriculture (USDA), works to meet such
need.
“Additionally, BCAP will provide funding for producers of
eligible renewable crops within a select geographical
area to receive payments up to 75 percent of the cost of
establishing the crop and annual payments for up to 15
years for crop production,” [2]. Once a geographical
area within the U.S. is approved by the USDA as a pro-
FSA news release, dated 3 Feb 2010 and
titled, Biomass Crop Assistance Program
to Spur Production of Renewable Energy,
Job Creation — A Vermont Elementary
School that will replace 100% of its fossil
fuel consumption with biomass is one of
the early beneficiaries of the BCAP program. Two additional examples of early
BCAP beneficiaries include, “a start-up
pellet company that uses locally-grown
agriculture residues from Iowa farms, and
a rural electric cooperative that displaces
fossil fuels with woodchips to generate
low-cost electricity in northeastern Georgia,” [2].
ject area, producers are eligible for establishment payBioenergy & Sustainability
49
ments—to help get biomass crops planted.
Program History
The BCAP was created through the 2008 Farm Bill. In
May of 2009, a Presidential initiative launched a Biofuels
In Brief: How BCAP Works
Interagency Working Group to build a foundation for accelerated deployment of advanced biofuels. One month
BCAP provides assistance to support the
later, the USDA issued the Notice of Funds Availability
production of eligible biomass crops on
(NOFA) for “matching payments” for the collection, har-
land within approved BCAP project
vest, storage and transportation component of BCAP. In
areas. In exchange for growing eligible
February of 2010, the USDA suspended NOFA due to
crops, the Farm Service Agency will pro-
issues with proposed BCAP rules—later that year in Oc-
vide annual and establishment payments. tober, the USDA issued the final BCAP rules and regulations, [3].
FSA will also provide matching payments
to eligible material owners at a rate of $1
The intention of BCAP is to shrink the financial risk that
for each $1 per dry ton paid by a qualified
farmers, ranchers and forest landowners may face.
biomass conversion facility up to $45 per
Therefore, the assistance program provides incentive
dry ton delivered to the biomass conver-
payments to those who invest in the “production, hav-
sion facility. est, storage and transportation of new first-generation
energy crops that displace hydrocarbon-based materials
now used for heat, power and vehicle fuel.” Matching
payments are available for each participant but payments are discontinued after two years of start-up.
BCAP Eligible Crops
Eligible crops include renewable biomass,
with the exception of crops eligible to receive a payment under the Commodity
Applying for and Qualifying as a Biomass
Conversion Facility
Title of the 2008 Farm Bill and plants that
A biomass conversion facility may apply for qualification
tial to become invasive or noxious, [4].
online at http://www.fsa.usda.gov/bcap. Online applica-
Such crops as hard and softwood chips,
tions will be forwarded to FSA’s State offices for proc-
bark, legumes, non-yard waste grasses
essing which will culminate with assignment of a unique
and vines, corn cobs and stover, sugar-
facility identification number.
cane bagasse, rice straw, and wheat
Applying for Matching Payments by Eligible
Material Owners
An eligible material owner may apply for a matching
are invasive or noxious, or have the poten-
straw. Download a complete and detailed
list of BCAP Eligible Materials as of December 21, 2010.
payment at their county FSA office. FSA will only approve matching payments for deliveries to a qualified
biomass conversion facility, [5].
Bioenergy & Sustainability
50
Conclusions
Federal renewal energy policy is driving and providing incentives for bioenergy production. Renewable fuel
standards for ethanol are currently being met with production of corn-grain ethanol. But, with the pending
use of E15 and expectations that cellulosic ethanol production quotas will not likely be met in the near future,
the bioenergy future is uncertain. If corn-grain ethanol production increases so will its impact on water resources. Expect continued tweaking of federal bioenergy policy and incentives.
Self-test Questions - Unit 3.4
1.
The growth of corn-grain ethanol production in the U.S. can be attributed to federal tax credits, renewable fuels
standards, and research and development funding.
a. True
b. False
2.
The same federal policies that drive ethanol production indirectly drive the land use and water resources impacts of
bioenergy production.
a. True
b. False
3.
The Renewable Fuels Standard suggests voluntary minimum-use volumes of biofuels in the national transportation
system.
a. True
b. False
4.
If the minimum-use volumes of cellulosic-based ethanol are not met in the near future what will happen?
a. corn-based ethanol production will increase to meet the demand
b. large imported volumes of ethanol will fill the gap
c. congress will revise the standard to a lower level
d. research will increase production to meet the demand
e. any of the above
1.
Answer: A. True
2.
Answer: A. True
3.
Answer: B. False. The RFS mandates these minimum use standards.
4.
Answer: E. No answer is certain, and likely some form of all of these may occur.
Bioenergy & Sustainability
51
Water Resources:
Issues & Opportunities in
Bioenergy Generation
BIOEN3
References
Unit 3.1
The Water Cycle
1. University of Illinois WW2010 Project located at:
http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/hyd/bdgt.rxml
2. Water level changes in the Ogallala Aquifer in: Cunningham, William P. et. al. 2003, “Environmental Science, 7th edition, McGraw Hill.
3. Reeves, H.W., 2010, Water Availability and Use Pilot—A multiscale assessment in the U.S. Great Lakes
Basin: U.S. Geological Survey Professional Paper 1778, 105 p.
4. www.cgd.ucar.edu/cas/Trenberth/.../ClilmChg39_667-694.pdf
5. U.S. Geological Survey, 1984, National water summary 1983-Hydrologic events and issues: U.S. Geological Survey Water-Supply Paper 2250, 243 p.
6. http://geochange.er.usgs.gov/sw/changes/natural/et/
7. Hanson, R.L., 1991, Evapotranspiration and Droughts, in Paulson, R.W., Chase, E.B., Roberts, R.S., and
Moody, D.W., Compilers, National Water Summary 1988-89--Hydrologic Events and Floods and
Droughts: U.S. Geological Survey Water-Supply Paper 2375, p. 99-104.].
8. http://www.cof.orst.edu/cof/fe/watershd/pdf/Chris%20Graham%20Final%20Thesis.pdf
9. Al-Kaisi, M. 2000. Crop water use or evapotranspiration. Integrated Crop management. IC-484(11),
p.85-86. http://www.ipm.iastate.edu/ipm/icm/2000/5-29-2000/wateruse.html
10. Brady, N.C. and R.R. Weil. 2007, The Nature and Properties of Soils. 14th ed. Prentice Hall. ISBN:
013227938X .
11. Scheffer.M. and S.R. Carpenter. 2003. Catastrophic regime shifts in ecosystems: linking theory to observations. Trends in Ecology and Evolution 18(12): 648-656.
12. DeFraiture. C. Berndes, G. Biofuels and Water. Biofuels: Environmental Consequences & Implications on
Changing Land Use. p 139 – 152.
13. Biofuel Variety Trials Factsheet, USDA-ARS and WSU, Prosser, WA found online at:
http://www.bioenergy.wa.gov/OilSeed.aspx
14. Dohleman, F.G. and S. P. Long. 2009. More Productive Than Maize in the Midwest: How Does Miscanthus Do It? Plant Physiology 150:2104-2115
http://www.extension.org/pages/Miscanthus_for_Biofuel_Production
Bioenergy & Sustainability
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15. Gerben-Leenes, P.W. et al. 2008. Value of Water.Research Report Series No. 29. UNESCO-IHE Institute
for Water Education, Delft, the Netherlands in collaboration with University of Twente, Enschede, the
Netherlands, and Delft University of Technology, Delft, the Netherlands ;
www.unesco-ihe.org/.../Report29-WaterFootprintBioenergy.pdf
16. Committee on Water Implications of Biofuels Production in the United States, National Research Council.
2008. Water Implications of Biofuels Production in the United States. National Academies Press. 88 p.
17. http://www.docstoc.com/docs/27478999/ENVIRONMENTAL-IMPACTS-OF-BIOFUEL-PRODUCTION-A
ND-PROCESSING ; Hargrove. W.L. Environmental Impacts of Biofuel Production and Processing.
Kansas State University. PowerPoint.
18. http://michigan.gov/documents/deq/wb-gwdischarge-CCNA-FS_282752_7.pdf
Unit 3.2
Watershed Impacts from Bioenergy
1. Mockma, D.L. 2006. Capacity of soils to assimilate wastewaters from food processing facilities. 20052006 GREEEN Project Alternatives for Food Processor’s Wastewater. Michigan State University. 11p.
Available online at:
http://www.egr.msu.edu/~safferma/Research/Greeen/Deliverables/Assimilation%20Capacity%2012-8-2
007.pdf
2. http://onlinemanuals.txdot.gov/txdotmanuals/hyd/nrcs_runoff_curve_number_methods.htm
3. Irrigation and Water Use. USDA Economic Research Service. Available online at:
http://www.ers.usda.gov/briefing/WaterUse.
4. Irrigation Water Use. Water Science for Schools. USGS website. Availabe at:
http://ga.water.usgs.gov/edu/wuir.html.
5. http://www.iitap.iastate.edu/gccourse/issues/society/ogallala/ogallala.html
6. Glantz, Michael, ed., 1989: Forecasting by analogy: societal responses to regional climatic change.
Summary Report, Environmental and Societal Impacts Group NCAR, 77 pp.
www.kerrcenter.com/publications/ogallala_aquifer.pdf
7. Guru, M.V., J.E. Horne, 2000. The Ogallala Aquifer. The Kerr Center for Sustainable Agriculture,Poteau,
Oklahoma
8. J. Jones. 2005. Volatile organic compounds in streams near wastewater outfalls, Rockdale County,
Georgia. Proceedings of the 2005 Georgia Water Resources Conference, held April 25–27, 2005, at the
University of Georgia http://ga.water.usgs.gov/publications/other/gwrc2005/pdf/GWRC05_JJones.pdf)
9. DBP: TRIHALOMETHANES, FACT SHEET. U.S. Department of Interior, Bureau of Reclamation)
http://www.usbr.gov/pmts/water/publications/reportpdfs/DBP%20THMs.pdf
10. Petersen, J.C., Adamski, J.C., Bell, Davis, J.V., Femmer, S.R., Freiwald, D.A., and Joseph, R.L., 1998,
Water Quality in the Ozark Plateaus, Arkansas, Kansas, Missouri, and Oklahoma, 1992-95. U.S. Geological Survey Circular 1158 < http://pubs.usgs.gov/circ/circ1158/>, Major issues and findings Nutrients
and bacteria, on line at http://pubs.usgs.gov/circ/circ1158/circ1158.4A.html
Biofuel Development Impacts on Water Quality
1. Secchi, S. and B.A. Babcock. 2007. Impact of High Corn Prices on Conservation Reserve Program
Acreage, Iowa Ag Review, Center for Agricultural and Rural Development, Spring 2007, Vol. 13 No. 2
http://www.card.iastate.edu/iowa_ag_review/spring_07/article2.aspx
2. Franti, T.G., M.L. Bernards, P.C. Hay, and R.W. Pryor. 2010. Protecting Surface Water Quality: Adoption
of Agricultural Best Management Practices in the Lower Big Blue River Basin. University of NebraskaLincoln Cooperative Extension, EC730. 14 pp.
Landscape Conversion to Bioenergy Crops
1. Shapiro, C.A., D.L. Holshouser, W.L. Kranz, D.P. Shelton, J.F. Witkowski, K.J. Jarvi, G.W. Echtenkamp,
L.A. Lunz, R.D. Frerichs, R.L. Brentlinger, M.A. Lubberstedt, M. McVey McCluskey, and W.W. Stroup.
2001. Tillage and management alternatives for returning Conservation Reserve Program land to crops.
Agron. J.:93:850-862.
2. Shapiro, Charles A. and Gary W. Hergert. 2009. Soil Fertility Considerations for land coming out of Conservation Reservation Program (CRP). University of Nebraska-Lincoln Extension. NebGuide G1970.
Ecological Intensification
1. International Plant Nutrition Institute
http://www.ipni.net/ipniweb/portal.nsf/0/6467B7229A075DFF8525720800242553
2.
Cassman, K.G. 1999. Ecological intensification of cereal production systems: Yield potential, soil quality,
and precision agriculture, in Proc. Natl. Acad. Sci (USA): Vol. 96 (11): 5952-5959.
3. Evans, L.T., 1993. Crop Evolution, Adaptation, and Yield. Cambridge University Press, Cambridge, UK,
500 pp.
4. Tilman, David, Kenneth G. Cassman, Pamela A. Matson, Rosamond Naylor & Stephen Polasky. (2002)
Agricultural sustainability and intensive production practices. Nature Publishing Group, Vol. 418, 8
August 2002. Retrieved from: Google Scholar.
5. Grassini, Patricio and Kenneth G. Cassman. 2011. “Corn Yield Potential and Input-Use Efficiency.” UNL
Department of Agronomy and Horticulture, Presented at UNL Extension Crop Clinics, Jan. 2011.
Additional Reference
Grassinia, P., J.Thorburnb, C.Burrc, and K.G..Cassman. 2010. High-yield irrigated maize in the Western U.S.
Corn Belt: I. On-farm yield, yield potential, and impact of agronomic practices. Field Crops Res. Vol. 120
(1):142-150. doi: 10.1016/j.fcr.2010.09.012
Unit 3.3
Bioenergy Water Use in Ethanol Production
1. http://www.neo.ne.gov/statshtml/121.htm
2. Chiu, Y.-U., B. Walseth, and S. Suh., Water Embodied in Bioethanol in the United States, Environ. Sci.
Technol. 2009, 43, 2688–2692. (http://pubs.acs.org/doi/full/10.1021/es8031067).
3. Keeney, D. and M. Muller. 2006. Water Use by Ethanol Plants: Potential Challenges. Environment and
Agriculture Program, Institute for Agriculture and Trade Policy, Minneapolis, MN, October 2006.
(http://www.agobservatory.org/library.cfm?refid=89449)
4. Consumptive Water Use in the Production of Bioethanol and Petroleum Gasoline, Wu, M., M. Mintz, M.
Wang, and S. Arora, Center for Transportation Research Energy Systems Division, Argonne National
Laboratory. www.transportation.anl.gov/pdfs/AF/557.pdf
5. 2008 National Dry Mill Corn Ethanol Survey, Steffen Mueller, University of Illinois at Chicago
<http://www.erc.uic.edu/PDF/mueller/ethanol_survey_report.pdf
6. Renewable Fuels Association <www.ethanolrfa.org>
7. Ethanol Producer Magazine,
http://www.ethanolproducer.com/articles/6801/public-opinion-counts-on-water
8. From “POET Biorefining Water Use” presented by Doug Berven, October 28, 2009, at Heartland Regional Water Initiative Conference,
http://www.heartlandwq.iastate.edu/NR/rdonlyres/22B951AE-57DC-4482-80BC-E49105AD053E/1167
87/POETethanol.pdf
Crop Growth Water Use in Ethanol Production
1. Corn Grain as an Ethanol Feedstock. Crop Watch: Bioenergy, University of Nebraska-Lincoln, <
http://cropwatch.unl.edu/web/bioenergy/corn>
2. “Water Embodied in Bioethanol in the United States,” was published in the March 10 issue of Environmental Science & Technology <http://pubs.acs.org/doi/full/10.1021/es8031067>.
3. National Research Council. Water Implications of Biofuels Production in the United States; National
Academies Press: Washington, D.C., 2008; pp 19-25.
4. de Fraiture, C.; Giordano, M.; Liao, Y. Biofuels and implications for agricultural water use: Blue impacts of
green energy. Water Policy 2008, 10 (S1), 67–81.
5. Pimentel, D. Ethanol fuels: Energy balance, economics, and environmental impacts are negative. Nat.
Resour. Res. 2003, 12 (2), 127–134.
6. Pimentel, D.; Patzek, T. W. Ethanol production using corn, switchgrass, and wood; biodiesel production
using soybean and sunflower. Nat. Resour. Res. 2005, 14 (1), 65–76.
7. Grassini, Patricio and Kenneth G. Cassman. “Corn Yield Potential and Input-Use Efficiency.” UNL Department of Agronomy and Horticulture.
8. Consumptive Water Use in the Production of Ethanol and Petroleum Gasoline M. Wu, M. Mintz, M.
Wang, and S. Arora, 2009. Center for Transportation Research Energy Systems Division, Argonne National Laboratory, January 2009, ANL/ESD/09-1
9. Perlack, et al. 2005, Biomass as Feedstock for a Bioenergy and Bioproducts Industry: Technical Feasibility of a Billion-Ton Annual Supply, USDA and DOE report, April 2005.
10. Pate, R., M. Hightower, C. Cameron, and W. Enfield. 2007. Overview of Energy-Water Interdependencies and The Emerging Demands on Water Resources, Sandia National Laboratories, Albuquergue, NM,
SAND 2007-1349C.
Water Use by Woody Biomass
1. “Cellulosic Ethanol.” Renewable Fuels Association. http://www.ethanolrfa.org/pages/cellulosic-ethanol
2. Tolbert, V. and A. Schiller. “Environmental Enhancement Using Short-Rotation Woody Crops and Perennial Grasses as Alternative to Traditional Agricultural Crops.” Biofuels Feedstock Development Program,
Oak Ridge National Laboratory, Oak Ridge, TN. http://bioenergy.ornl.gov/papers/misc/envenh95.html
3. http://www.heartlandwq.iastate.edu/Bioenergy/Information+Briefs/Cellulosic+Production/Miscanthus+-+
Perennial+Biofuel+Crops.htm
4. Cassman, K., V. Eidman, and E. Simpson. “Convergence of Agriculture and Energy: Implications for Research and Policy.” CAST Commentary (2006).
5. State Energy Conservation Office (Texas). http://www.seco.cpa.state.tx.us/re_ethanol_cellulosic.htm
6. CALS Bioenergy Feedstock Project: Energy Crops. Cornell University, College of Agriculture and Life
Sciences. http://nybiofuels.info/GENERALINFORMATION/BIOMASS/Pages/EnergyCrops.aspx
7. Perrin, R., K. Vogel, M. Schmer and R. Mitchell. “Farm-Scale Production Cost of Switchgrass for Biomass.” University of Nebraska. Bioenerg. Res. (2008) 1:91-97.
8. Sarath, G., R. Mitchell, S. Sattler, D. Funnell, J. Pedersen, R. Graybosch, and K. Vogel. “Opportunities
and roadblocks in utilizing forages and small grains for liquid fuels.” University of Nebraska-Lincoln. J Ind
Microbiol Biotechnol (2008) 35:343-354.
9. United Nations Foundation http://www.energyfuturecoalition.org/biofuels/fact_ethanol_cellulose.htm
10. Vadas, P., K. Barnett, and D. Undersander. “Economics and Energy of Ethanol Production from Alfalfa,
Corn, and Switchgrass in the Upper Midwest, USA.” University of Nebraska. Bioenerg. Res. (2008)
1:44-55.
11. Varvel, Gary E., K. Vogel, R. Mitchell, R. Follett, and J. Kimble. “Comparison of Corn and Switchgrass on
Marginal Soils for Bioenergy.” USDA Ag Research Service—Lincoln, Nebraska.
http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1246&context=usdaarsfacpub&sei-redir=1#s
earch="switchgrass+yield+compared+to+corn
12. https://utextension.tennessee.edu/publications/Documents/SP702-C.pdf
13. http://www1.eere.energy.gov/office_eere/pdfs/sbir_greenwood_case_study.pdf
14. https://netfiles.uiuc.edu/dhungana/www/BMBE%20Nov%2005%202007(in%20Press).pdf
15. http://news.msue.msu.edu/news/article/establishing_miscanthus_as_a_bioenergy_crop_can_be_challen
ging
16. http://www.sciencedaily.com/releases/2007/07/070710064827.htm
17. http://www.nnfcc.co.uk/publications/nnfcc-crop-factsheet-miscanthus
18. http://bioweb.sungrant.org/Technical/Biomass+Resources/Agricultural+Resources/New+Crops/Short+R
otation+Woody+Crops/Hybrid+Poplar/Default.htm
19. http://www.wa-hay.org/Proceedings/08%20Proceedings/Potential%20Biofule%20Crops%20-%20Wood
ward.pdf
Unit 3.4
Agriculture-based Biofuels Policy
1. Schnepf, Randy, Coordinator. “CRS Issue Statement on Agriculture-Based Biofuels.” Congressional Research Service. 3 March 2010.
<http://www.circleofblue.org/waternews/wp-content/uploads/2010/08/agriculture-based_biofuels.pdf>.
2. Milbourn, Cathy. EPA News Release, “EPA Grants E15 Waiver for Newer Vehicles/A new label for E15 is
being proposed to help ensure consumers use the correct fuel.” Release date 13 October 2010. Retrieved from:
<http://yosemite.epa.gov/opa/admpress.nsf/0/BF822DDBEC29C0DC852577BB005BAC0F>.
Biomass Crop Assistance Program (BCAP)
1. United States Department of Agriculture, Definition of program
http://www.fsa.usda.gov/FSA/webapp?area=home&subject=ener&topic=bcap
2. Effects of policy issue – USDA and FSA
http://www.apfo.usda.gov/FSA/newsReleases?area=newsroom&subject=landing&topic=ner&newstype=
newsrel&type=detail&item=nr_20100203_rel_0046.html
3. BCAP Rules and Regulations
http://www.michaelbest.com/files/Uploads/Documents/BCAP%20Webinar%20Slides.pdf
4. BCAP Eligible Crops
http://askfsa.custhelp.com/app/answers/detail/a_id/1402/session/L3RpbWUvMTI5ODEzMjI1NC9zaWQ
vV1dDOEsqbWs%3D
5. Applying for Matching Payments
http://askfsa.custhelp.com/app/answers/detail/a_id/1394/session/L3RpbWUvMTI5ODEzMjI1NC9zaWQ
vV1dDOEsqbWs%3D
6. Effects of BCAP – posted 13 Jan 2011
http://www.renewableenergyworld.com/rea/blog/post/2011/01/the-practical-effects-of-the-revised-bcap
1
7. University of Idaho – BCAP Analysis of Proposed Options
http://www.cnrhome.uidaho.edu/documents/PAG_IB_no_12_3-27-10.pdf?pid=119153&doc=1
Franti, T., R. Broz, E. Burkett, R. Dow, E. Jobman, and C. Norrie. 2011. Water Resources: Issues and Opportunities in Bioenergy Generation. Module 3 in S. Lezberg and J. Mullins (eds.) Bioenergy and Sustainability
Course. On-line Curriculum. Bioenergy Training Center.
http://fyi.uwex.edu/biotrainingcenter/
Water Resources:
Issues & Opportunities in
Bioenergy Generation
BIOEN3
Project Collaborators
The Bioenergy Training – Modular Course Series is a multi-state collaborative effort involving content experts,
peer reviewers, instructional designers, editors and coordinators from throughout the North Central region
and beyond.
Curriculum Development Team and author affiliations:
University of Illinois Extension
Iowa State University
Kansas State Research and Extension
Michigan State University Extension
University of Minnesota Extension Service
University of Missouri Extension
University of Nebraska-Lincoln
North Dakota State University
South Dakota State University
University of Wisconsin-Extension
eXtension Farm Energy Community of Practice