Nonrenewable Energy
Resources
99% of the energy that heats the
earth and our buildings comes from
the sun, the remaining 1% comes
mostly from burning fossil fuels.
78% of the commercial energy
(sold in market) we use comes from
nonrenewable fossil fuels
Burning fossil fuels causes more
than 80% of US air pollution and
more than 80% CO2 emissions.
Questions to Keep in Mind
1. What is the net energy yield for the resource?
2. How much will it cost to develop or phase in and use?
3. What constructive subsidies will be used to promote
R&D?
4. How will dependence on the resource affect national
and global economic and military security?
5. How vulnerable is the resource to terrorism?
6. How will extracting, transporting, and using the
resource affect (a) environment; (b) human health; (c)
climate
7. Should true costing be considered?
Net Energy
Net energy is the amount of high-quality usable energy
available from a resource after subtracting the energy
needed to make it available for use.
Net energy ration = useful energy produced:energy
used to produce it
ie. 10:8 (10/8) for every 10 units of energy in oil we
have to use and waste 8 units of energy. The net energy
ratio is 10/8 or 1.25. The higher the ratio, the greater
the net energy.
When the ratio is less than 1, there is a net energy loss.
COAL
Coal is an abundant energy
resource that is burned mostly to
produce electricity and steel.
Coal is the world’s most abundant
fossil fuel.
Mostly in USA (25%), Russia
(16%), and China (12%)
US coal reserves could last up to
300 years, but an increase of just
4% per year could reduce that to 64
years!
COAL FORMATION
Advantages of Coal
 Abundant known world reserves (200 years
at current world consumption rate)
 Unidentified world reserves (1000 years at
current consumption rate)
 USA (300 years at current consumption rate)
 High Net Energy Yield
 US subsidies keep prices low
Disadvantages of Coal
 60 % surface mined (strip mining) in USA
 40 % subsurface mined
 Occupational hazards include “black lung
disease”, underground fires and collapse.
 20% of coal becomes fly ash, boiler slag, and
sludge. Releases mercury and radioactive
particles into air.
 Expensive to process and transport
Environmental Impacts From
Coal
 Releases CO into atmosphere
 Contributes 35% of all CO2 into atmosphere
(global warming)
 Contributes 70 % of all SO2 (acid deposition)
 Contributes 30% of all NO and NO2 (acid
deposition)
 Produces more fly ash, toxic metals, and
radioactive particles than a nuclear power
plant.
Solid Coal Converted to Gas
and Liquid Fuels
Coal can be converted to synthetic natural
gas, methanol (CH3OH), or synthetic gasoline
through coal liquefaction (synfuels).
Advantages: easily transported through
pipelines, produces less air pollution, large
supply.
Disadvantages: low net energy yield,
expensive to build plants, acceleration of coal
depletion, large amounts of water required,
releases large amounts of CO2, more
expensive than coal, mercury and PAH’s
released into environment.
Coal Gasification
Coal Liquefaction
Acid Deposition SOx
Sulfur in the atmosphere comes from burning
bituminous coal, smelting, and organic decay.
90% is from human sources.
Sulfur in the atmosphere combines with water vapor to
form hydrogen sulfite gas.
SO2 (s) + H2O (v)
H2SO3(v)
Hydrogen sulfite reacts with oxygen gas to form sulfuric
acid.
H2SO3 + ½ O2
H2SO4
Acid Deposition NOx
Major sources of nitrogen oxides include
combustion of coal, oil, natural gas, forest fires,
bacterial action in soil, volcanic gases, and
lightening-induced atmospheric reactions
Nitrogen monoxide reacts with oxygen gas to
produce nitrogen dioxide gas
NO(v) + ½ O2(v)
NO2(v)
Nitrogen dioxide reacts with water vapor in the
atmosphere to produce hydrogen nitrite and
hydrogen nitrate
2NO2(v) + H2O(v)
HNO2 (v) + HNO3(v)
Effects of Acid Deposition on
Aquatic Ecosystems
 Below a pH of 4.5, most fish cannot survive
 Acid deposition releases Al3+ ions attached
to soil particles into nearby lakes. These ions
asphyxiate many fish, causing excess mucous
formation which clogs their gills
 Norway, Sweden, Canada and Northeastern
USA have 1000’s of “fishless” lakes because
they are downwind of coal burning plants.
Effects of Acid Deposition on
Forests
Forests and crops are harmed by leaching essential
plant nutrients such as calcium and magnesium salts
from soils. This reduces the plants productivity and
the ability of soils to buffer or neutralize acid inputs.
Acid deposition weakens trees and makes them
more susceptible to other stresses such as severe cold,
diseases, insect attacks, drought, and harmful mosses.
Cloud forests are hardest hit from sitting in acid
clouds. These areas often have thin soils with little
buffering capacity.
Effects of Acid Deposition on
Human Health and Culture
Contributes to human
respiratory disease
(bronchitis and asthma)
Contributes to toxic
metal leaching such as
copper from water pipes.
Damages statues,
national monuments,
buildings, car finishes, and
grave headstones.
Climate Change
Water vapor (H2O), carbon dioxide
(CO2), methane (CH4) and nitrous oxide
(N2O) influence climate by warming the
lower troposphere and the earth’s
surface.
Greenhouse Effect
Natural Greenhouse Effect – without it the
planet would be a cold and mostly lifeless
planet
Incoming wave =
visible light wave
(short wave)
Outgoing wave =
infrared wave (long
wave)
“Unnatural Greenhouse Effect”
There is a high probability (90-99%)
that increasing concentrations of
greenhouse gases in the troposphere are
from burning fossil fuels, deforestation,
and agriculture.
Temperature Changes
Past temperature
changes are estimated
by the analysis of
radioisotopes in rocks
and fossils, plankton
and radioisotopes in
ocean sediments, ice
cores from ancient
glaciers, tree rings, and
historical records.
Absorption of Radiant Heat
due to CO2 in Atmosphere
Methane Increases in the
Atmosphere
Nitrous Oxide Increases in
Atmosphere
Oceans Moderate Global
Temperature
The oceans help moderate global temperatures by
removing 29% of the excess CO2 we pump into the
atmosphere as part of the anthropogenic carbon
cycle
The oceans also absorb heat from the atmosphere
and slowly transfer it to the deep ocean.
Ocean currents act as giant convection convection
currents transferring heat from the equator to the
poles.
Other Synergistic Effects From
Outdoor Air Pollution
Increased CO2 in the troposphere could increase
photosynthesis, but this would only be temporary.
Aerosols and soot produced by the burning of
coal and other fossil fuels can warm or cool the
atmosphere.
Warmer air can release methane gas stored in
bogs, wetlands, and tundra soils and make the air
even warmer.
Effects of Global Warming
Agricultural changes ( shifting
food-growing areas, changes in crop
yields, increased irrigation demands,
increased pests, diseases and weeds
in warmer latitudes.)
Water Resources (changes in
water supply, decreased water
quality, drought, flooding, snowpack
reduction, melting of glaciers)
Effects of Global Warming
Forests (shifts and changes in
composition, disappearance of
high altitude forests, increased
forest fires, loss of wildlife habitat
and species).
Biodiversity (Extinction of
some plant and animal species
especially those in high latitude
biomes, loss of habitat, disruption
of aquatic life)
Effects of Global Warming
Sea Level and Coastal Areas (rising sea
levels, flooding of low lying islands and
coastal cities, estuaries, wetlands, and coral
reefs, beach erosion, disruption of coastal
fisheries, aquifer salt water intrusion).
Human Health ( disruption of food and water
supplies, spread of tropical diseases to
temperate areas, increased deaths from heat,
increased water pollution from coastal
flooding).
Effects of Global Warming
 Human Population (Increased deaths from
heat and disruption of food supplies,
increased environmental refugees,
increased migration).
 Weather Extremes (prolonged heat waves
and droughts, increased flooding from more
frequent, intense and heavy rainfall events
in some areas).
Air Temperature Increases
Partial Solutions
Particle Emission Control Devices
1. Electrostatic Precipitator – utilized for fly
ash reduction and to remove particulate
emissions by treating air with an electrical
charge to capture the suspended particles in
the gas flow. The particles are collected on an
array of charged parallel plates above the
collection hoppers in the precipitator box.
Electrostatic Precipitator
Partial Solutions
2. Scrubbers (wet and dry) – are used to
trap particles from gaseous emissions
from fossil fuel burning power plants
especially. The scrubbers prevent most
of these particles from entering the
atmosphere especially NOx and Sox,
where they can change into
environmentally damaging acid
deposition.
Wet Scrubber
Partial Solutions
3. Fluidized Bed Combustion – use heated beds of sandlike material suspended (“fluidized”) within a rising
column of air to burn many types and classes of fuel.
This technique results in a vast improvement in
combustion efficiency of high moisture content fuels.
The scrubbing action of the bed material on the fuel
particles enhances the combustion process by stripping
away the CO2 and char layers that normally form
around fuel particles. This allows O2 to reach the
combustible material much more readily and increases
the rate and efficiency of the combustion process.
Fluidized Bed Combustion
Combustion example, the burning of propane is:C3H8 + 5O2 → 3CO2 + 4H2O
PREVENTION IS BEST!
Maldives