Final Report
Life Cycle Analysis of Road
Transport Biofuels
Prepared for the London Borough of Camden
By
Sustainable Transport Solutions Ltd
Final Report
August 2008
LCA of Road Transport Biofuels
Report
Prepared for:
London Borough of Camden
By
Sustainable Transport Solutions Ltd
Report Details:
Report Type
Report Reference:
Report Version:
Date:
Final Report
LCA Road Transport Biofuels
Final Report v7
th
18 August 2008
Quality Control:
Author(s)
Quality Check
Project Manager
Last Edited
Guy Hitchcock, Ben Lane
Ben Lane
Guy Hitchcock
th
18 August 2008
This report has been prepared for London Borough of Camden in accordance
with the terms and conditions of appointment. Sustainable Transport Solutions
Ltd cannot accept any responsibility for any use of or reliance on the contents
of this report by any third party.
Contact Details
Guy Hitchcock
Sustainable Transport Solutions Ltd
Crossways,
Hilltop Lane
Kilve,
Bridgwater
Somerset TA5 1SR
Tel: 0870 4289096
Email: [email protected]
www.sustainable-transport.net
Final Report
August 2008
LCA of Road Transport Biofuels
Contents
1. Introduction ...................................................................... 1
2. Methodology .................................................................... 2
3. Review of Greenhouse Gas Emissions Data................... 4
3.1. Biodiesel ..................................................................... 4
3.2. Bioethanol .................................................................. 6
3.3. Biomethane ................................................................ 8
3.4. Land use impacts ..................................................... 10
4. Review of Air Quality Emissions .................................... 12
4.1. Biodiesel ................................................................... 12
4.2. Bioethanol ................................................................ 14
4.3. Biomethane .............................................................. 15
4.4. Fuel production emissions........................................ 16
5. Life Cycle Analysis Results............................................ 18
5.1. Fuel cycle results ...................................................... 21
5.2. Cleaner Drive analysis ............................................. 22
6. Conclusions ................................................................... 26
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LCA of Road Transport Biofuels
1. Introduction
The London Borough of Camden, and the Clear Zone Partnership, has been active in exploring
new vehicles and fuels in order to reduce pollution emissions to tackle local air quality and climate
change. The Council are interested in understanding the air quality and climate change impacts of
biofuels in order to inform policy objective related to the use and promotion of biofuels. This study
compares the life cycle emissions for different biofuels.
With the introduction of the European Biofuels Directive and in the UK the Renewable Transport
Fuels Obligation (RTFO), a number of authorities are now using biofuels within their own fleets.
The most common fuel at present is biodiesel which is generally being used in a blend with
mineral diesel, with the level of biodiesel ranging from 5% to 30%. The primary benefit of biofuels
is the reduction of life cycle greenhouse gas emissions, but there have been some concerns about
their potential impact on air quality.
This LCA study looked at the three main biofuels, biodiesel, bioethanol and biomethane and how
they compare on a life cycle emissions impact basis. The main biofuels covered in the study
were:

Biodiesel – produced from UK rape seed oil (to produce rape methyl ester or RME),
Malaysian palm oil (PME) and from local used cooking oil (UCO);

Bioethanol – produced from UK wheat, UK sugar beet, and Brazilian sugar cane;

Biomethane – produced from local municipal waste, sewage waste and landfill.
The study reviewed existing and, where practical, local information on the life cycle emissions from
the production and use of these fuels, and provides an assessment of their use in light duty
vehicles. The assessment covers the following emissions impacts:

Climate change impacts – considering the main transport greenhouse gas (GHG)
emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O),

Local air quality impacts – considering the regulated emissions and specifically nitrogen
oxides (NOx) and particulate matter (PM). Also where relevant and where data is available
other emissions such as of volatile organic compounds including aldehydes.
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LCA of Road Transport Biofuels
2. Methodology
In the case of road transport, pollutant emissions are generated during production of the fuel,
1
vehicle manufacture, vehicle operation, and vehicle recycling/ disposal. These emissions can be
categorised as either direct, produced during operation of the vehicle, or as indirect, being
generated during the production of the fuel, and the manufacture and disposal of the vehicle.
A full life cycle assessment needs to include both direct and indirect emissions (as defined above).
For conventional fuels, the direct greenhouse gas (GHG) emissions will form the majority of total
emissions, however, indirect emissions will also be significant – in the case of light-duty vehicles,
2
indirect emissions account for around 15% of life cycle emissions. However, in the case of
biofuels, the full GHG benefit of the fuel can only be assessed by considering indirect emissions
as this is where the environmental impacts (and benefits) of the fuel occur.
Regarding regulated pollutants (including NOx and particulates) that impact on air quality (AQ), the
picture is somewhat different with both fuel production and fuel use (vehicle operation) generating
significant proportions of the emissions, the percentage depending on the type of fuel. Also, as
vehicle emission regulations tighten the proportion of emissions associated with fuel production
increases.
Although in most cases (e.g. petrol and diesel cars), indirect emissions associated with the fuel
cycle exceed the level of emissions generated during vehicle manufacture, assembly and
disposal, vehicle cycle emissions are not insignificant, and need to be included in a full life cycle
assessment. These are usually estimated using established modelling techniques due to the lack
3
of data that is available in the public domain.
Figure 1 Transport fuel and vehicle life cycles – see new diagram below
1
A full transport impact assessment would also include an analysis of the impacts associated with the
extraction of raw materials, infrastructure requirements, impacts on land use; resource depletion; and waste
disposal issues. However, these issues are beyond the scope of this study.
2
SMMT Annual CO2 Report: 2006. Society of Motor Manufactures and Traders, 2006.
3
These techniques are employed by the GREET and Ecolane LCA studies: GREET 2.7, The Transportation
Vehicle-Cycle Model, 2007; and Life Cycle Assessment of Vehicle Fuels and Technologies. Conducted by
Ecolane on behalf of the London Borough of Camden, 2006.
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LCA of Road Transport Biofuels
Figure 1 summarises the fuel and vehicle life cycles and identifies which process stages produce
the majority of emissions.
The focus of most life cycle assessment research is on fuel cycle GHG emissions and therefore
there is a great deal of high quality data available on this aspect. The primary work that has been
done on this, on which the study will draw, includes:
o
DfT (2007). Carbon reporting within the Renewable Transport Fuel Obligation –
Methodology, 2007;
o
Concawe (2006). Well-To-Wheels Analysis Of Future Automotive Fuels And Powertrains
In The European Context. Report by Concawe, Eurcar and the EU Joint Research Centre,
2006;
o
GREET (2006). Development of GREET 2.7 Fuel Cycle Model for Transportation Fuels
and Vehicle Technologies. Argonne National Laboratory, USA;
o
DTI (2000). The Report of the Alternative Fuels Group of the Cleaner vehicle task Force
Report. Department of Trade and Industry, Automotive Directorate, The Stationery Office,
London, 2000.
In contrast, research that focuses on the fuel cycle AQ emissions (eg NOx and particulates), is
much more scarce. Therefore the data on these emissions are less robust. In addition, direct
emissions are influenced by vehicle emissions control technology and the European emissions
legislation that they are designed to meet (Euro standards) - these technologies are continuing to
developing and the impact of these technologies on biofuel emissions is not always clear.
Therefore, for the reasons described above, the study set the following LCA boundaries to define
the scope of the analysis:

Greenhouse gas and regulated emissions assessment is carried out for the full fuel cycle,
including direct and indirect emissions;

Greenhouse gas and regulated emissions assessment is carried out for the vehicle cycle,
which will be estimated using established modelling techniques;

The regulated pollutant emissions covered in the analysis is primarily NOx and particulates,
with others included where necessary (eg volatile organic compounds) and where suitable
data is available;

The regulated emissions assessments reported in two parts (direct and indirect emissions),
as it is predominantly the direct emissions that affect local air quality in Camden.

The Cleaner Drive methodology will be used to assess the environmental impacts of
quantified emissions.
This report is set out in three main sections covering the work of the study:
 Section 3 sets out the review of the fuel cycle GHG emissions for each of the fuels.
 Section 4 reviews the data available on air quality emissions, primarily at tail pipe.
 Section 5 then provides the results for the fuel life cycle analysis for both GHG and
regulated emissions, it also provides the results of the Cleaner Drive analysis.
Finally Section 6 sets out some conclusions from the data and analysis.
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LCA of Road Transport Biofuels
3. Review of Greenhouse Gas Emissions Data
The two main sources of data reviewed for the GHG emissions were:
 Well-to-wheels analysis of future automotive fuels and power trains in the European
context’, Concawe/EUCAR/JRC, 2007;
 Carbon and sustainability reporting in the Renewable Transport Fuels Obligation,
Renewable Fuels Agency (RFA), 2008
The RFA data represents the most up-to-date and UK specific data set available, while the
Concawe study provides addition detailed analysis. For the biomethane data we have also drawn
on information held by STS that was used to develop an, as yet, unpublished toolkit on
biomethane for the Centre of Excellence on Fuels Cell and Low Carbon Technologies (CENEX).
In all cases the GHG data presented in this section covers all the stages of fuel production from
growing the crops through to production of the fuel to factory gate or import terminal in the UK.
However, it does not include distribution and retail in the UK. The analysis also includes the
4
carbon content of the fuel itself and accounts for the energy content of the fuel. This allows the
calculation of what is known as the GHG intensity of the fuel expressed in CO2 equivalents
(accounting for CO2, CH4 and N2O emissions) per MJ of fuel. This is then essentially the inherent
carbon or GHG emissions associated with a fuel, allowing fuels to be compared on a more like for
like basis.
This data, however, does not take into account the impact of use in different vehicle technologies,
and in particular the different efficiencies of the various vehicle technologies. Therefore it is a fuel
comparison comparing fuels on an energy basis, not a vehicle and fuel comparison. The final
vehicle stage, which accounts for differences in vehicle technology and exhaust emissions (e.g.
comparing petrol and diesel engines) is done in Section 5 to give the full life-cycle results,
including vehicle impacts, and expressed in emissions per vehicle km.
3.1.
Biodiesel
Biodiesel is an alternative to fossil diesel and is produced from vegetable oils. The conversion
process is a fairly simple chemical reaction which splits the glycerine out of the oil to form an ester.
The reaction is carried out by adding methanol or ethanol to the oil, with an additional catalyst, to
produce a methyl or ethyl ester, which is what we term biodiesel. The three representative routes
for biodiesel that were selected for this study are:
 UK sourced rapeseed, converted into a methyl ester (RME). UK sourced rape sheet has
been chosen as representative for an RME, and will be very similar to other European
produced RME’s.
 Malaysian palm oil, converted into a methyl ester (PME). Malaysia along with Indonesia
are the main sources of palm oil currently being used, and are very similar in the GHG
emissions.
 Used cooking oil (UCO) collected and processed into methyl ester. This is cooking oil
that is collected locally in the London area.
In practice any commercial biodiesel production operation may use a range of feedstock oils to
produce their biodiesel, rather than a single oil. The oils will be brought on the oil markets and
blended at the production stage. Current feedstock oils used to produce biodiesel fuels used in
4
The carbon content of fossil fuels is calculated as the carbon emitted from complete combustion of the
fuel. For the biofuels the carbon content is assumed to be zero, as the carbon has been absorbed in
growing of the plant.
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LCA of Road Transport Biofuels
5
the UK include a mixture of soy, rape seed, palm oil, tallow and UCO. Given the similarities of the
lifecycle greenhouse gas emissions of US SME (from soy) and RME, and (separately) also of
tallow and UCO based fuels, the three biodiesels analysed by this study (RME, PME and UCO)
represent the full spectrum of emissions benefits offered by biodiesel fuels.
The production pathway covered by the LCA analysis data in the RFA and Concawe studies is
shown in Table 1 below:
Table 1 Description of biodiesel production stages
RME
PME
UCO
Farming inputs to
Farming inputs to
Not included
growing the crop
growing the crop
Crop processing
Energy use for drying Production of palm oil Not included
the rape seed
on site
Feedstock transport
Transport of seed to
Transport of raw
Not included
crusher
palm oil to refinery
Feedstock processing Crushing of seed to
Refining of palm oil
Not included
produce rape seed
oil and by product
crush cake
Feedstock transport
Assumed crushed at
Assume refining
Collection of used oil
same site as
happens at
from local area with
conversion plant
conversion site
40km
Conversion
Inputs for conversion Conversion of palm
Conversion of used oil
of rape oil to RME,
oil to PME and by
into FAME and by
and by product
product glycerine
product glycerine
glycerine.
Biodiesel transport
None assumed
Import of PME into
None assumed
the UK from Malaysia
Stage
Crop Cultivation
In this analysis the distribution of the fuel is not included and so it is looking purely at the fuel
production process to the factory gate. This can then be compared to fossil diesel to the same
point in the life cycle analysis. Both the RFA and Concawe data cover emissions of CO 2, CH4 and
N2O and express this in CO2 equivalent terms. Table 2 shows the emissions associated for each
of the fuel production phases described above for the three study fuels from the RFA data set.
The data is given per kg of CO2 per tonne of fuel, and this is converted into g CO2/MJ for
comparison with a base UK diesel. These comparison results are also shown in Figure 2.
Table 2 RFA GHG emissions data by production stage for biodiesel
Feedstock
Country
Crop
Rape seed
Palm oil
UCO
UK
Malaysia
UK
CO2 Emissions per stage, kg/tonne fuel
Transport Process
Transport Conversion Total
71
29.0
-468.0
0.0
471.0
2048.0
520
39.0
109.0
248.0
471.0
1711.0
0
0.0
0.0
8.0
471.0
479.0
Process
1945
324
0
CO2
%
g/MJ
Reduction
55.1
36.3%
46.0
46.8%
12.9
85.1%
Note: Relative to UK diesel at 86.4 g CO2e/MJ;
PME sheeting emissions are showing under the second transport column.
The range of CO2 savings compared to fossil diesel are from 85% for UCO to 36% for UK rape
seed. These results are broadly similar to the Concawe data, which gives a 46% saving for
European average rape seed against European average diesel. So typically a commercial
biodiesel produced from a range of feedstock oils might be around a 50% GHG saving against
fossil diesel.
5
Renewable Fuels Agency, April-May 2008 Monthly Report. URL:
http://www.dft.gov.uk/rfa/reportsandpublications/rtforeports.cfm.
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LCA of Road Transport Biofuels
The significant savings in GHG emissions from a UCO base biodiesel arise from the fact that all
the emissions associated with growing the feedstock oil are not allocated to the fuel but rather to
the initial food use. Conversely when you look a biodiesel from rape seed the majority of the
emissions are associated with crop production, and are related to nitrous oxide emissions from soil
tillage and use of fertilizers. In this case more sustainable agricultural practices with reduced
tillage and the use of none fossil fuel fertilisers could substantially improve the GHG balance for
RME. Malaysian palm oil (from existing plantations in cases with no associated land use changes
– see Section 3.4) out performs standard UK sourced rape seed, even with the transport
requirements, as agricultural process uses much fewer inputs than rape seed.
Figure 2 GHG intensity of biodiesel compared to fossil diesel
3.2.
Bioethanol
Bioethanol is generally used as an alternative to petrol; in low blends in normal petrol vehicles,
6
and in high blends in flexible fuel vehicles. The fuel is made from the fermentation of starch or
sugar crops to produce the ethanol. The three main production sources identified as
representative for this study were as follows:
 Ethanol from wheat produced in the UK, which like rape seed will be representative of
most wheat across the UK;
 Ethanol from sugar beet produced in the UK;
 Ethanol from sugar cane produced and processed in Brazil, which is the main imported
source of sugar cane ethanol at present.
Unlike biodiesel, ethanol is always produced from a single feedstock as the conversion process is
feedstock specific. However, when buying ethanol the final product may be sourced from a
6
Several manufacturers, including Ford, Volvo and Saab, offer 'Flex-Fuel' Vehicles (FFVs) that run on any
percentage petrol-ethanol blend (up to E85) or on conventional petrol – the engine management system
automatically detects which fuel is being used and adjusts the timing accordingly making the vehicles fuelflexible. Over 15,000 flex-fuel versions of the Ford Focus have already been sold in Sweden, where there are
nearly 200 filling stations selling E85 bioethanol fuel.
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LCA of Road Transport Biofuels
number of different processors, as the processed ethanol will be the same in all cases. But in
general you are more likely to be using ethanol from a single type of feedstock, compared with
biodiesel which will more usually be made from a mixture of feedstock oils. Current feedstock
crops used to produce the majority of bioethanol fuels used in the UK include sugar cane (from
7
Brazil) and sugar beet (primarily from the UK).
The production path considered in the analysis of ethanol is described below in Table 3:
Table 3 Description of bioethanol production pathways
Wheat
Sugar beet
Sugar cane
Farming inputs to
Farming inputs to
Farming inputs to
growing the crop
growing the crop
growing the crop
Crop processing
Energy use for drying None
None
the wheat
Feedstock transport
Transport of wheat to Transport of sugar
Transport of sugar
ethanol plant
beet to ethanol plant
cane to ethanol plant
Conversion
Ethanol production
Ethanol production
Ethanol production
using grid electricity
using grid electricity
using waste sugar
and natural gas.
and natural gas.
cane bagasse as
Credit given for byenergy source.
product distillers
grains used as
animal feed.
Biodiesel transport
None assumed
Import of ethanol into None assumed
the UK from Brazil
Stage
Crop Cultivation
As with biodiesel distribution of the fuel is not included and so it is looking purely at the fuel
production process to the factory gate (or import terminal for Brazilian ethanol). This can then be
compared to fossil petrol to the same point in the life cycle analysis. Table 4 shows the emissions
associated for each of the fuel production phases described above for the three study fuels from
the RFA data set. The data is given per kg of CO2 per tonne of fuel, and this is converted into g
CO2/MJ for comparison with a base UK petrol. These comparison results are also shown in Figure
3.
Table 4 RFA data for ethanol production stages
Feedstock
Country
Crop
Process
Wheat
UK
1275
Sugar beat UK
530
Sugar Cane Brazil
245
Note: Relative to UK petrol at 84.8 gCO2e/MJ
CO2 Emissions, kg/tonne
Transport Conversion Transport Total
49
68
231
176
645
49
0
268
CO2
%
g/MJ
reduction
1623
60.6
28.6%
1351
50.4
40.6%
665
24.8
70.7%
This shows a range of GHG savings from 70% for Brazilian sugar cane to 28% for UK wheat. The
good results for the Brazilian sugar cane arises due to its low input agricultural process and the
fact that the standard process energy is the zero carbon bagasse waste from the sugar cane – i.e.
the part of the cane not used as a feedstock to produce the bioethanol is used as a fuel to provide
energy for the ethanol production process. Wheat ethanol, like biodiesel from rape seed, has
most of its emissions associated with the crop cultivation. Sugar beet performs better than wheat,
as it is a less intensive cultivation process.
However, there are significant variations in the way ethanol can be processed and this is shown in
two additional pathways that are covered by the Concawe data, and might be considered best
practice conversion processes:
7
Renewable Fuels Agency, April-May 2008 Monthly Report. URL:
http://www.dft.gov.uk/rfa/reportsandpublications/rtforeports.cfm.
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LCA of Road Transport Biofuels


Wheat ethanol where the stillage by-product and wheat straw are used as a fuel for power
generation;
Sugar beet ethanol where the beet waste is used for power generation in a biogas plant.
The data for these two pathways is shown below in Table 5. This shows that a best practice
process for wheat ethanol has a much lower level of CO2 emissions and is comparable to or better
than Brazilian sugar cane ethanol. Similarly the best practice route for producing sugar beet
ethanol is considerably better in CO2 terms than the standard practice.
Table 5 Best practice ethanol production pathways in the Concawe study
Fuel
Feedstock
Path
CO2
Ethanol
Ethanol
Ethanol
Ethanol
Wheat
Wheat
Sugar beet
Sugar beet
Standard
Best
Standard
Best
48.5
0.2
49.1
19
Emissions, g/MJ
%
CH4
N2O
GHG (CO2)
reduction
0.13
0.026
59.2
31.0%
-0.03
0.056
16.2
81.1%
0.13
0.018
57.5
33.0%
0.03
0.034
29.7
65.4%
Note: relative to European average petrol at 85.8 gCO2e/MJ
Figure 3 GHG emissions for bioethanol production
Note: Concawe data (wheat 2, Sugar beet 2) normalised to RFA data for consistency
3.3.
Biomethane
Biomethane is produced from the anaerobic digestion (AD) of organic material, such as organic
waste or agricultural residues. The raw biogas produced from the AD process needs to be
upgrade to about 95% methane for use as a vehicle fuel and is then known as biomethane. With
light duty vehicles the fuel is usually used in bi-fuel CNG/petrol vehicles.
The coverage of biomethane in both the RFA and Concawe data is more limited than with the
other fuels, however, combining data from these studies with data that STS has collected
specifically on biomethane GHG LCA data was estimated for the following primary pathways:
 Municipal waste (MSW) collected locally and treated in an anaerobic digestion system
and upgraded to provide biomethane. Process energy used is a combination of biogas
generated and imported electricity. The digestate from the process is assumed to be
spread back to land as a fertiliser.
 Sewage waste treated in the same way as MSW, with imported electricity, and the
residue spread to land to replace fertiliser.
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LCA of Road Transport Biofuels

Collection of landfill gas and upgrading to biomethane vehicle fuel quality.
The key elements of the production pathway considered for biomethane are a bit simpler and are
as follows:
 Transport of the feedstock – this is the collection and transport of the municipal waste, but
is assumed zero for sewage and landfill.
 AD process – this is the actual digestion process and it is assumed that the raw biogas is
used to provide process heat and electrify requirements are imported from the grid. For
landfill gas this process occurs natural in the land fill with no energy inputs.
 Upgrading – this is the upgrading process required to clean up the raw gas and compress
it for use as a vehicle fuel. The process energy is assumed to be electricity imported from
the grid.
The analysis also includes methane losses from the AD and upgrading process as a separate
element, and gives a credit from the AD digestate being used as a fertiliser and replacing fossil
fertilisers. The GHG emissions results for each of these stages, along with losses and credits, for
the three main pathways are shown in Table 4 below. Each of the pathways shows around a 5060% reduction in emissions compared to petrol.
Table 6 Base biomethane GHG emissions estimates
Yield
Emissions/stage g CO2e/MJ biomethane
%
Path
MJ/tonne Transport
AD
Upgrade
Losses
Credits
Total
reduction
MSW imported elec
1996
6.4
16.2
8.14
10.3
-0.78
40.26
52.5%
Sewage import elec
1568
0
16.2
8.14
10.4
-0.78
33.96
60.0%
Landfill import elec
2354
0
0
6.5
29.2
0
35.7
57.9%
Note: Relative to UK petrol at 84.8 gCO2e/MJ
The two key assumptions that effect these results are the overall system losses, since methane is
a strong greenhouse gas it will have a significant effect overall, and what fuel is used for the AD
and upgrading process. It terms of system losses an initial 1% was assumed but if this was as
high as 5%, as has been suggested to us by some system providers, it has a significant impact on
the results. Similarly the base case assumes imported electricity with the biogas itself used only
for heating, however, it is quite common for biogas plants to have combined heat and power
(CHP) systems running on the biogas providing both heat and electricity. This again has a
significant impact on the results.
Results for these alternative scenarios are shown in Table 7 below. These results now show a
GHG saving compared to petrol ranging from only 23.6% when 5% losses are assumed through to
83.9% for sewage gas using a biogas CHP for heat and electricity. A further scenario has been
added estimating the emissions for liquefied landfill gas using landfill gas CHP for the process
energy. This final scenario reflects the biomethane being produced from landfill by Gasrec who
are running a pilot with Camden at present.
Table 7 Alternative biomethane production scenarios
Path
MSW Imported elec 5%
MSW CHP elec
Sewage CHP elec
Landfill CHP
Landfill CHP Liquid
Final Report
Yield
MJ/tonne Transport
AD
1915
6.4
1158
6.4
910
0
2020
0
2100
0
Emissions/stage g CO2e/MJ biomethane
%
Upgrade
Liquify
Losses
Credits
Total
reduction
16.2
8.14
0
34.8
-0.78
64.76
23.6%
0
0
0
17.8
-0.78
23.42
72.4%
0
0
0
14.4
-0.78
13.62
83.9%
0
0
0
33.2
0
33.2
60.8%
0
0
0
27.9
0
27.9
67.1%
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August 2008
LCA of Road Transport Biofuels
Figure 4 GHG emissions for biomethane production
3.4.
Land use impacts
One of the biggest discussions about the potential environmental problems with biofuels has been
around changes in land use associated with requiring more land to grow both food and fuel crops.
The change of concern is using previously unmanaged forest or grass land on which to grow
biofuel feedstocks. The impact of this change is both terms of biodiversity effects and carbon
impacts. The carbon impacts arise from changes in carbon stocks (stored carbon) in the existing
biomass (trees, grassland, etc) and soil types, when switching to cultivation.
These land use changes can occur in two ways: either direct or indirect. Direct land use change is
when a biofuel crop is directly grown on previous forest of grass land. Indirect land use change is
when a biofuel crop is displacing food production into new areas of forest or grassland and so can
be indirectly considered to have caused the land use change. Clearly indirect effects are much
harder to determine and allocate to a fuel.
For feedstocks sourced in the UK there is unlikely to be any direct land use change as most land
that is suitable for agricultural use is already being used or has been left fallow as set aside. The
one exception would be if long established grazing land was ploughed up to be used as crop land.
However, indirect effects may be occurring in the UK if using wheat or rape seed for example that
it might otherwise be exported as a food crop. In this case this food will need to be grown
elsewhere and this may cause land use impacts.
With feedstock from developing countries the concern about direct land use change is greater, as
in many of these countries there are large areas of forest or grass land that could be turned over
to agricultural use and used for growing biofuel feedstocks. Again indirect effects may also occur
if biofuel plantations are pushing food crops onto sensitive land.
The calculation of the CO2 equivalent impact of these changes is difficult to calculate as it depends
on country, type of previous land use, type of feedstock being grown and biofuel being produced.
The RFA has made estimate of these impacts using a methodology developed by the IPPC. The
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LCA of Road Transport Biofuels
data relating direct land use impacts for each of our studied biofuel pathways is shown in Table 8
below. In all cases if land change has happened, then the impact on GHG emissions will wipe out
any benefit that the biofuel had over the fossil fuel equivalent. Clearly land use issues do not
affect fuels produced from waste feedstocks such as UCO and biomethane.
Fuel
Biodiesel
Biodiesel
Bioethanol
Bioethanol
Bioethanol
Table 8 Direct land use impacts on biofuel GHG emissions
Feedstock
Country
Previous land use impact, g CO2e/MJ
Crop land
Forest
Grassland
Rapeseed
UK
0
520
137
Palm oil
Malaysia
0
157
51
Wheat
UK
0
438
116
Sugar beet
UK
0
228
60
Sugar cane
Brazil
0
319
88
This presents a somewhat unsettling picture for traditional liquid biofuels and suggests that as
demand for food and fuel grows we will undoubtedly have detrimental impacts in terms of carbon
emissions. However, the picture is quite complex and there are a number of reasons why land
use impacts may not be as bad as some fear or indeed are attributable to biofuels:
 New technologies allow a wider range of non-food and waste materials to be used as
feedstocks.
 There is potentially still significant amounts of unused agricultural land that may be
developed;
 There are significant improvements in agricultural efficiency that can be made, and these
will be driven through investment made possible through higher commodity prices;
 The destruction of forest land may be driven primarily for demand for wood, and then only
subsequently used for food or fuel crops.
8
The recent Gallagher review of indirect effects of biofuels carried out by the RFA concluded that
these impacts were occurring, but that with suitable controls a sustainable biofuels industry was
possible. However, whatever the arguments we are moving to a world with reduced dependence
on oil where we need to make our needs for food, fuel and materials fit the earth’s production
capacity. This means biofuels can only be part of the solution alongside significant reduction in
demand for transport fuels.
8
‘The Gallagher Review - of the indirect effects of biofuel production’, Renewable Fuels Agency, July 2008
Final Report
Page 11
August 2008
LCA of Road Transport Biofuels
4. Review of Air Quality Emissions
The level of analysis and data collection on fuel cycle air quality emissions (such as NOx and PM)
is much less than for GHG emissions. Clearly there are plenty of data available on the direct
exhaust emissions from conventional fuels and engine technologies, and their effect on air quality.
There is quite of bit of data and discussion on the emissions from alternative fuels, including
biofuels. However, it is quite hard to compare this data is it is for a range of test cycle and vehicle
technologies. Also as emission standards get tighter, the relative impact of alternative fuels on
vehicle emissions will decrease. However, what is important is an understanding of how these
fuels interact with new emissions reduction technology.
This section therefore focuses on the effect of biofuels on exhaust emissions, as this is where
most of the available data lies and it is also these direct emissions that are of most concern from
local air quality. The indirect emissions will be covered in less detail, and both sets of data are
combined for the fuel life cycle assessment in Chapter 5.
4.1.
Biodiesel
Most of the data available on biodiesel appears to be for heavy duty vehicles, trucks and buses,
and much is for pre-2000 vehicles. Clearly this raises the question about how applicable this is for
light duty vehicles and the effect on newer vehicles. A literature review by the Dutch energy
9
agency Novem in 2004 concluded that although results were quite variable, biodiesel would
appear to reduce emissions of CO, HC and PM, but slightly increase NOx emissions. There also
seemed to be a consistent picture in lower emissions of aromatic HC’s and PAHs.
10
This conclusion reflects the results of a major USEPA study in 2002 on biodiesel and the most
commonly held perceptions of the emissions impacts of biodiesel. Figure 5 is taken direct from
the EPA study and shows NOx increasing with biodiesel blend levels and all other emissions
decreasing. These results caused some concerns, since NOx is a major urban air pollutant and
lead to a number of US states banning its use. This prompted further study by the National
Renewable Energy Laboratory (NREL) in 2004 that carried out direct measurements and literature
11
reviews . This concluded that the EPA results were from limited vehicles types and from a wider
vehicle group ‘on average there appears to be no net effect (on NOx emissions), or at most a very
small effect of ± 0.5%’.
One concern with regards the US data is that the base US diesel has a much higher sulphur
content than in the EU (EU EN590 diesel <50ppm sulphur, US LSD <300ppm sulphur). A more
12
recent German study of B100 and low sulphur diesel provides some answers here. This study
concluded the following:
 NOx emissions were broadly similar across all fuels, and at worst a little higher for
biodiesel under high loads;
 CO and HC emissions were generally 30-40% lower than standard diesel;
 PM emissions were about 40% lower than standard diesel, but the Swedish MK1 diesel
which is virtually sulphur free had similar PM emissions to the biodiesel.
9
‘Compatibility of pure and blended biofuels with respect to engine performance, durability and emissions’,
Senter-Novem, 2004
10
‘A comprehensive analysis of biodiesel impacts on exhaust emissions’, US EPA, 2002
11
‘Effects of biodiesel blends on vehicle emissions’, NREL, 2006
12
‘Fuel economy and environmental characteristics of biodiesel and low sulphur fuels in diesel engines’,
Krahl et. Al., 2005
Final Report
Page 12
August 2008
LCA of Road Transport Biofuels
Figure 5 US EPA trend lines for the emissions impact of biodiesel on
heavy-duty vehicles
Even these German results are only relative to a Euro II emission standard vehicle, and so the
differences one would expect to be less for more recent vehicles with lower standard emissions.
However, the Novem study concludes that the low sulphur content of biodiesel makes it favourable
for the application of exhaust after treatments such as oxidation catalysts and particulate filters
and so should continue to see some benefits over standard diesel.
The NOVEM review (2004) quotes research that suggested that the various found in NOx and PM
emissions, particularly NOx emissions was related to fuel parameters such as density, cetane
number and iodine number that will vary depending on the feedstock oils used for the biodiesel.
However, there seems little data on this to really assess the impact of different feedstock oils.
Another important issue regarding the air quality impacts of biodiesel fuel is fuel quality. Most of
the European research findings relate to high-quality biodiesels that meet accepted biofuel
standards (such as EN14214 originally based on the German RME fuel specification). For
biodiesel fuels which have specifications that differ markedly from established (and developing)
standards, there remains some uncertainty regarding the emissions impacts for these fuels. For
example, the fuels produced by individuals using ‘do-it-yourself’ esterification kits is likely to be
highly variable in composition. A number of companies now also offer straight vegetable oils or
SVOs (also known as pure plant oils or PPOs) and engine conversion kits for private and business
use.
There is some initial evidence published by the Department for Transport that the regulated
emissions for light-duty vehicles using SVOs is highly variable, and can be significantly worse than
13
baseline ULSD is some cases. However, there is also some evidence that the comparison
studies conducted to date have not reflected the highest quality SVOs or engine conversions that
14
are commercially available. It seems that, to assess the regulated emissions performance of
biodiesel fuels not conforming to known standards, more research is required.
13
Final Report of Test Programme to Evaluate Emissions Performance of Vegetable Oil Fuel on Two Light
Duty Diesel Vehicles. DfT, 2004. URL: http://www.dft.gov.uk/rmd/project.asp?intProjectID=11610.
14
Folkecenter for Renewable Energy, Denmark, 2004. URL: http://journeytoforever.org/biodiesel_SVOAnso.html.
Final Report
Page 13
August 2008
LCA of Road Transport Biofuels
In summary, therefore, we will make the following assumptions about the impact of (high-quality)
biodiesel conforming to established fuel standards, relative to standard diesel (<50PPM sulphur)
for a Euro IV vehicle, for the full life cycle emissions analysis:
Table 9 Estimated impact of biodiesel in regulated emissions
Pollutant
B20
B100
CO
-6%
-30%
HC
-8%
-40%
NOx
+0.5%
+2%
PM
-6%
-30%
4.2.
Bioethanol
The data on ethanol emissions appears to be more limited than that on biodiesel and quite
variable. For many years ethanol has been used in the US in low blends as an oxygenate to help
reduce CO emissions from petrol engine vehicles. However, this has not been common in Europe
and, with the introduction of catalysts, is of marginal value. However, with the Biofuels directive
and the RTFO blends in petrol up to 5% are likely to increase. In general it would seem that the
impact of these blends on regulated emissions is negligible. The only exception to this is the
tendency for low blend ethanol fuels to have increase vapour pressure and so increased
evaporative emissions at refuelling stations.
With higher blend ethanol fuels up to E85 the emissions performance is again variable. The
Novem review in 2004 concluded that the regulated emissions were little different to the petrol
equivalent. However, in terms of unregulated emissions there does seem to be consistent
evidence of significantly increase aldehyde emissions, which are a by product of ethanol
combustion, but decreases in aromatics such as benzene. A similar conclusion was reached by
15
review of the sustainability impacts of ethanol carried out in the US in 2005 :
‘E10 is of debatable air pollution merit (and may in fact increase the production of
photochemical smog); offers little advantage in terms of greenhouse gas emissions,
energy efficiency or environmental sustainability; and will significantly increase both the
risk and severity of soil and groundwater contamination. In contrast, E85 offers significant
greenhouse gas benefits, however it will produce significant air pollution impacts, involves
substantial risks to biodiversity, and its groundwater contamination impacts and overall
sustainability are largely unknown.’
This potential problem with emissions of unregulated emissions, in particular increases aldehydes
which are a precursor to peroxy acetyl nitrate (PAN) that causes eye irritation and respiratory
16
conditions, was studied by a team at Stanford University . This study pulled together data on
exhaust emissions and then modelled the potential cancer and ozone related risks to health.
There summary of results on emissions data is shown in Table 10 below and shows the large
increase in aldehyde, and specifically acetaldehyde. Overall it concluded that E85 had a similar
cancer risk potential to gasoline, but may have increased risks of ozone related health impacts.
17
A much more recent study from Sweden (Ecotraffic, 2008 ) assessed the emissions from modern
Euro 4 passenger cars under a range of temperatures. In general this study provided similar
results to that found by the earlier reviews with little difference in regulated emissions, but higher
15
‘Ethanol in Gasoline, environmental impacts and sustainability review article’. Niven 2005
‘The effects of ethanol (E85) versus gasoline vehicles on cancer and mortality in the United States’,
Jacobson, Stanford, 2007
17
‘An exhaust characterisation study based on regulated and un regulated tail pipe and evaporative
emissions from bi-fuel and flexi-fuel light duty passenger cars fuelled by petrol, bioethanol (E70, E85) and
0
0
biogas, tested at ambient temperatures between -7 C and + 22 C.’ Ecotraffic, 2008
16
Final Report
Page 14
August 2008
LCA of Road Transport Biofuels
aldehyde emissions. The Swedish study also showed that the aldehyde emissions got
0
significantly worse at low temperatures (-7 C), and in addition regulated emissions were also
generally worse at low temperatures for the ethanol fuelled vehicles. At these low temperatures
increases in PM emissions was also noted for E85, and this was associated with higher polycyclic
aromatic hydrocarbon (PAH) levels.
Table 10 Summary of % change in ethanol emissions results relative to petrol
Source: Jacobson, 2007 – column headings relate to study reference and year
Overall the data suggests that high blends of ethanol may present a risk of increased air pollution
from higher aldehyde emissions when compared to petrol. With respect to the over fuel cycle
emissions analysis the study will assume no impact on regulated emissions from using ethanol
compared to petrol. However, in terms of unregulated emissions a significant increase of a factor
of 10 will be assumed for aldehydes (specifically acetaldehyde), and a reduction in aromatics
(benzene and 1-3 butadiene) of 50%.
4.3.
Biomethane
Biomethane is essentially the same as compressed natural gas (CNG) and is used in conventional
CNG vehicles. As such the emissions of biomethane vehicles will be the same as those of other
CNG vehicles. The emissions benefits of CNG vehicles are fairly well established being generally
similar to or lower than equivalent petrol emissions, and having NOx and PM benefits against
diesel. This is illustrated in the certification data for the Volvo S60 and V70 cars in Table 11.
Table 11 Regulated emissions for the Volvo S60 and V70
Pollutant
CO
HC
Nox
PM
S60, 2.4l, Euro4
V70, 2.4l, Euro4
Emissions, g/km
% change vs
% change vs
Diesel
Petrol
CNG
Diesel
Petrol
Diesel
Petrol
CNG
Diesel
Petrol
0.188
0.5
0.283
150.5%
56.6%
0.202
0.548
0.467
231.2%
85.2%
0.023
0.056
0.046
200.0%
82.1%
0.023
0.052
0.067
291.3%
128.8%
0.19
0.073
0.037
19.5%
50.7%
0.225
0.055
0.014
6.2%
25.5%
0.001
0.002
18
A recent Swedish study on bioethanol and biogas vehicles provides some detailed data on
emissions from a bi-fuel CNG vehicle. This concluded that biomethane emissions were lower than
petrol emissions for all regulated and unregulated emissions with the exception of HC emissions.
The increase in HC emissions was related solely to increases in un-burnt methane emissions,
which would appear to be worse with older catalysts. The problem with methane emissions is also
identified by the Concawe lifecycle study. This uses an assumption of a 4 fold increase in
methane emissions relative to a petrol vehicle.
18
Ecotraffic, 2008.
Final Report
Page 15
August 2008
LCA of Road Transport Biofuels
In summary biogas is potentially a very low emission fuel, with the potential to meet strict
emissions standards. These reduced emissions will provide an air quality benefit for biomethane
relative to petrol and diesel. The fuels only problem is with un-burnt methane emission, and this is
related to the effectiveness of the catalyst system. In terms of air quality these methane emissions
have little impact having very low ozone forming potential compared to HCs emitted from diesel
and petrol vehicles. Also even though CH4 emitted directly is a strong greenhouse gas, over the
whole lifecycle of the fuel as shown in Section 5, the total GHG emissions are still lower that petrol
or diesel.
Overall for the purposes of the life cycle assessment in this study we will assume the following:
 CO and PM emissions are the same as an equivalent petrol vehicle;
 Total HC emissions comparable to petrol, but CH4 emissions increased by factor of 4;
 NOx emissions are reduced by 50%.
4.4.
Fuel production emissions
This section focuses on the indirect (‘upstream’) air quality emissions associated with fuel
production. As mentioned previously, in contrast to the extensive research findings regarding
greenhouse gases, there is generally less published data regarding indirect pollutants. The main
reason for this lack of data is that, for conventional fuels, the most significant impacts of local
pollutants are caused by tailpipe emissions. However, this is not always the case for biofuels
which may generate the largest proportion of regulated emissions (CO, HC, NOx and particulates)
at the point of production. In these cases, it is therefore necessary to assess the extent of indirect
emissions for air pollutants so a lifecycle inventory can be completed.
That said, very few relevant data sources are available that quantify the upstream air pollutants for
different biofuels. Only two comprehensive recent studies are currently available: one published by
19
Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) ; and the
second is the Greenhouse gases, Regulated Emissions and Energy use in Transportation
20
(GREET) model from the U.S. Department of Energy's (DOE) Argonne National Laboratory. UK
data is available for some biofuels from the EU MEET Project (Fuel and Energy Production
21
Emission Factors, European Commission, ST-96-SC.204, 1997) , but this information dates back
22
to 1997.
For liquid biofuels, to assess the level of indirect pollutants, this study draws primarily on the
CSIRO data, and where data is not available, UK MEET data is used. In both cases, care is taken
to check the relevance to a UK 2008 context – any assumptions made in transferring the data to a
UK context are noted in the following text.
For biomethane, in the absence of any published data, the authors have made calculations of
indirect regulated emissions based on the existing information cited in the report. Tables 12 and
13 show the indirect fuel cycle emission used to inform this report (units are grams per GJ fuel
delivered).
19
The greenhouse and air quality emissions of biodiesel blends in Australia, Tom Beer et al. Australia's
Commonwealth Scientific and Industrial Research Organisation (CSIRO), KS54C/1/F2.29, 2007.
20
GREET model 2008. URL: http://www.transportation.anl.gov/modeling_simulation/GREET/index.html.
21
MEET Project. URL: http://www.inrets.fr/infos/cost319/MEETdeliverable20.pdf.
22
The DfT's Cleaner Fuels and Vehicles Division are currently commissioning a new study to assess GHG
emissions from UK fuel refineries; this is likely to update the results of the 1997 MEET report.
Final Report
Page 16
August 2008
LCA of Road Transport Biofuels
Table 12 Indirect regulated emissions for selected biodiesel fuels
Primary energy
On-board fuel
Energy Content
Typical density
Energy Content
Fuel PMs
Fuel NOx
Fuel CO
Fuel HCs
Crude oil
Units
MJ/kg
kg/litre
MJ/litre
gms/GJ
gms/GJ
gms/GJ
gms/GJ
Reference
ULSD
43.1
0.832
35.9
1.10
36.10
4.60
103.60
MEET
1997
Rape
Rape
Canola Palm oil
UCO
seed
seed
RME100 RME100 RME100 PME100 UCO100
37.2
37.2
37.2
36.8
36.8
0.890
0.890
0.890
0.890
0.890
33.1
33.1
33.1
32.8
32.8
18.50
3.13
76.64
12.07
1.36
242.20
158.00
229.30
54.50
35.60
137.00
35.00
16.10
22.40
8.40
77.90
142.00
59.60
16.10
16.90
MEET
CSIRO
CSIRO
CSIRO
CSIRO
1997
2000
2007
2007
2007
Table 13 Indirect regulated emissions for selected bioethanol and biomethane fuels
Primary energy
On-board fuel
Energy Content
Typical density
Energy Content
Fuel PMs
Fuel NOx
Fuel CO
Fuel HCs
References
Units
MJ/kg
kg/litre
MJ/litre
gms/GJ
gms/GJ
gms/GJ
gms/GJ
Crude oil
Wheat
ULSP
43.2
0.745
32.2
2.40
42.40
5.10
228.80
MEET
1997
E85
29.3
0.787
22.9
20.40
265.00
620.00
67.30
CSIRO
2000
Sugar
cane
E85
29.3
0.787
22.9
1.96
126.00
452.00
23.10
CSIRO
2000
MSW
Sewage
Landfill
MSW
Sewage
Landfill
BASE
47.1
n/a
n/a
15.02
568.24
106.73
475.01
STS
2008
BASE
47.1
n/a
n/a
14.77
559.77
105.44
474.59
STS
2008
BASE
47.1
n/a
n/a
4.01
151.91
28.61
128.79
STS
2008
CHP
47.1
n/a
n/a
0.47
15.63
2.40
1.59
STS
2008
CHP
47.1
n/a
n/a
0.00
0.00
0.00
0.00
STS
2008
LIQUID
47.1
n/a
n/a
0.00
0.00
0.00
0.00
STS
2008
For RME biodiesel, three datasets have been used for the analysis, one from the UK (MEET 1997)
and two from Australia (CSIRO 2000 and 2007; note that the 2007 data is for Canola a rape seed
derivate). For Palm Methyl Ester and Used Cooking Oils fuels, in the absence of any UK upstream
data, figures from the latest CSIRO 2007 study have been used. To account for differences in the
energy mix, all 2007 emission estimates are taken relative to baseline Ultra Low Sulphur Diesel of
the respective countries. For CSIRO 2000 data, relative information is not available, and therefore
is used as presented in the original CSIRO reports.
For 85% blended bioethanol fuels (E85), in the absence of any UK upstream data, CSIRO 2000
data is used. US data is available but is focussed on corn derived biofuels which are not included
in this study. The CSIRO data that includes wheat and sugar cane biofuels is used in the absence
of any UK figures. No data is available for sugar beet derived bioethanol.
In the case of biomethane fuel considered in this study, the authors have made calculations of
pollutant emissions based on the published Concawe data already cited. Where relevant, these
are calculated by estimating the upstream emissions associated with any electricity use and
transport movements (Rigid HGV data sourced from National Atmospheric Emissions Inventory).
As is the case for GHG emissions, a direct comparison of upstream pollutants for biofuels with
diesel and petrol baseline fuels needs to account for variations in fuel use; biofuels tend to
increase energy use per unit distance (MJ/km). In addition, all of the regulated emissions have
different levels of environmental impact; generally NOx and particulates have a higher
environmental significance than carbon monoxide and hydrocarbons. Therefore, assessing the
upstream air quality impact of each biofuel requires the use of an external costing methodology to
quantify the combined emissions impact (see Section 5.2).
However, it is possible to observe from the figures shown in Tables 10 and 11 that, upstream
pollutant emissions are increased for some biofuels as compared to diesel/petrol fuels. Unlike the
GHG emissions comparison of the biofuels assessed in this report, where indirect emission are
increased, these are not balanced by an equivalent of carbon absorption during crop growth, and
can (in some cases) lead to an increase in lifecycle pollutant emissions.
Final Report
Page 17
August 2008
LCA of Road Transport Biofuels
5. Life Cycle Analysis Results
Up to this point in the report, the focus has been on GHG and air quality emissions generated on a
per GJ delivered basis. This section uses the fuel use and (tailpipe) emissions performance for a
typical petrol and diesel passenger car to compare the emissions for biofuels with baseline fuels
on a per kilometre basis. The new element introduced into the calculation is fuel economy of a
given vehicle technology.
The passenger cars selected for the analysis are based on the latest Ford Focus diesel and petrol
models, and are taken to represent the latest engine and emission-control technologies (fuel
injection, diesel particulate filters, etc); for details of vehicle specifications see Table 14. The
engine sizes are also similar to the cubic capacities of the models used in the Concawe analysis
cited earlier in this report. Specifically these are:

Ford Focus 2.0 Duratorq TDCi (136PS) (+DPF) Manual 6-speed [2008];

Ford Focus 1.6 Duratec (100PS) Manual 5-speed [2008].
It should be noted, that these particular models may not be able to accept all of the biofuels
considered by the report. For example, the Focus 2.0 TDCi cannot be operated (under warranty)
on 100% biodiesel due to the use of the latest fuel injection systems. Also the 1.6 Duratec is not
the model in the Focus range designed to accept E85; there is a 1.8 Flex-Fuel version in the
range. However, these vehicles types and engine sizes represent the latest typical (and
comparable) petrol and diesel passenger cars used in the UK.
To calculate the total fuel cycle results for those biofuels considered in this study, the following
emissions are summed:
1. Tailpipe GHG emissions – for petrol/diesel, these are test cycle emissions as shown in
Table 14. For crop based biofuels, tailpipe emissions are taken as zero as carbon is
absorbed from the atmosphere during crop growth. For, E85 tailpipe emissions are
(effectively) reduced by 85%;
2. Upstream GHG emissions – for all fuels these are based on estimated on Concawe and
other cited data as discussed in Section 3;
3. Tailpipe regulated emissions – for petrol/diesel, these are test cycle emissions as shown
in Table 14. For biofuels, these emissions are estimated using the relative data and
assumptions as discussed in earlier Section 4;
4. Upstream regulated emissions – for all fuels these are based on cited data as discussed
in Section 4.4.
The total fuel cycle GHG and air quality emissions are shown in Table 14.
Final Report
Page 18
August 2008
LCA of Road Transport Biofuels
Table 14 Fuel-cycle emissions comparison for selected biofuels and petrol/diesel baseline
Fuelcycle emission comparison of Ultra Low Sulpur Diesel with 100% biodiesel fuels
Vehicle specification
Tailpipe emissions (g/km)
Fuelcycle emissions (g/km)
Kerb
Metric Mpg
wt
Comb Comb CO2
CO
HC
NOx
PMs
Fuel Type
PMs
ULSD
1300
5.5
51.4
144
0.056 0.012 0.208 0.003
0.005
RME (MEET97) 1300
6.1
51.4
151
0.039 0.007 0.212 0.002
0.039
RME (CSIRO00) 1300
6.1
51.4
151
0.039 0.007 0.212 0.002
0.008
RME (CSIRO07) 1300
6.1
51.4
151
0.039 0.007 0.212 0.002
0.156
PME
1300
6.1
51.4
151
0.039 0.007 0.212 0.002
0.026
UCO
1300
6.1
51.4
151
0.039 0.007 0.212 0.002
0.005
Base vehicle: Ford Focus 2.0 Duratorq TDCi (136PS) (+DPF) Manual 6-speed [2008]
NOx
0.279
0.697
0.529
0.671
0.320
0.283
CO
0.065
0.314
0.109
0.071
0.084
0.056
HC
0.216
0.163
0.292
0.127
0.039
0.041
SO2
0.094
0.137
0.137
0.137
0.135
0.135
CO2eq
172
110
110
110
91
26
CH4
0.002
0.001
0.001
0.001
0.001
0.001
N2O
0.008
0.008
0.008
0.008
0.008
0.008
CH4
0.014
0.014
0.014
N2O
0.005
0.005
0.005
CH4
0.014
0.058
0.058
0.058
0.058
0.058
0.058
N2O
0.005
0.005
0.005
0.005
0.005
0.005
0.005
Fuelcycle emission comparison of Ultra Low Sulpur Petrol with 85% bioethanol fuels
Vehicle specification
Tailpipe emissions (g/km)
Kerb
wt
Metric Mpg
Comb Comb CO2
CO
HC
NOx
Fuel Type
ULSP
42.2
159
0.547 0.072 0.050
1200 6.7
WHEAT-E85
42.2
159
0.547 0.072 0.050
1200 6.7
SUGAR-E85
42.2
159
0.547 0.072 0.050
1200 6.7
Base vehicle: Ford Focus 1.6 Duratec (100PS) Manual 5-speed [2008]
PMs
0.000
1.000
2.000
Fuelcycle emissions (g/km)
PMs
0.005
0.043
0.004
NOx
0.141
0.612
0.317
CO
0.558
1.861
1.505
HC
0.565
0.215
0.121
SO2
0.144
0.142
0.142
CO2eq
186
137
73
Fuelcycle emission comparison of Ultra Low Sulpur Petrol with 100% biomethane fuels
Vehicle specification
Tailpipe emissions (g/km)
Kerb
wt
Metric Mpg
Comb Comb CO2
CO
HC
NOx
Fuel Type
ULSP
42.2
159
0.547 0.072 0.050
1260 6.7
MSW BASE
58.6
122
0.547 0.072 0.025
1260 4.8
Sewage BASE 1260
4.8
58.6
122
0.547 0.072 0.025
Landfill BASE
58.6
122
0.547 0.072 0.025
1260 4.8
MSW CHP
58.6
122
0.547 0.072 0.025
1260 4.8
Sewage CHP
58.6
122
0.547 0.072 0.025
1260 4.8
Landfill LIQ
58.6
122
0.547 0.072 0.025
1260 4.8
Base vehicle: Ford Focus 1.6 Duratec (100PS) Manual 5-speed [2008]
Final Report
Page 19
PMs
0.000
0.000
0.000
0.000
0.000
0.000
0.000
Fuelcycle emissions (g/km)
PMs
0.005
0.034
0.034
0.009
0.001
0.000
0.000
NOx
0.141
1.315
1.296
0.370
0.060
0.025
0.025
CO
0.558
0.789
0.786
0.612
0.552
0.547
0.547
August 2008
HC
0.565
1.150
1.149
0.364
0.076
0.072
0.072
SO2
0.144
0.038
0.038
0.038
0.038
0.038
0.038
CO2eq
186
91
77
81
53
31
63
LCA of Road Transport Biofuels
Table 13 Life-cycle emissions comparison for selected biofuels and petrol/diesel baseline
Lifecycle emission comparison of Ultra Low Sulpur Diesel with 100% biodiesel fuels
Vehicle specification
Tailpipe emissions (g/km)
Lifecycle emissions (g/km)
Kerb
Metric Mpg
wt
Comb Comb CO2
CO
HC
NOx
PMs
Fuel Type
PMs
ULSD
1300
5.5
51.4
144
0.056 0.012 0.208 0.003
0.016
RME (MEET97) 1300
6.1
51.4
151
0.039 0.007 0.212 0.002
0.050
RME (CSIRO00) 1300
6.1
51.4
151
0.039 0.007 0.212 0.002
0.019
RME (CSIRO07) 1300
6.1
51.4
151
0.039 0.007 0.212 0.002
0.166
PME
1300
6.1
51.4
151
0.039 0.007 0.212 0.002
0.036
UCO
1300
6.1
51.4
151
0.039 0.007 0.212 0.002
0.015
Base vehicle: Ford Focus 2.0 Duratorq TDCi (136PS) (+DPF) Manual 6-speed [2008]
NOx
0.338
0.756
0.587
0.730
0.379
0.341
CO
0.190
0.438
0.234
0.196
0.208
0.181
HC
0.289
0.236
0.364
0.199
0.112
0.113
SO2
0.180
0.222
0.222
0.222
0.221
0.221
CO2eq
197
135
135
135
116
50
Impact Rating
CH4
0.047
0.046
0.046
0.046
0.046
0.046
N2O
0.008
0.008
0.008
0.008
0.008
0.008
AQ
23
35
31
43
22
22
GHG
54
37
37
37
32
14
ALL
41
36
35
39
28
17
Lifecycle emission comparison of Ultra Low Sulpur Petrol with 85% bioethanol fuels
Vehicle specification
Tailpipe emissions (g/km)
Kerb
wt
Metric Mpg
Comb Comb CO2
CO
HC
NOx
Fuel Type
ULSP
42.2
159
0.547 0.072 0.050
1200 6.7
WHEAT-E85
42.2
159
0.547 0.072 0.050
1200 6.7
SUGAR-E85
42.2
159
0.547 0.072 0.050
1200 6.7
Base vehicle: Ford Focus 1.6 Duratec (100PS) Manual 5-speed [2008]
PMs
0.000
0.000
0.000
Lifecycle emissions (g/km)
PMs
0.016
0.054
0.015
NOx
0.195
0.666
0.371
CO
0.672
1.975
1.619
HC
0.634
0.283
0.189
SO2
0.221
0.219
0.219
CO2eq
209
160
95
Impact Rating
CH4
0.055
0.055
0.055
N2O
0.005
0.005
0.005
AQ
24
25
17
GHG
57
35
23
ALL
44
31
21
Lifecycle emission comparison of Ultra Low Sulpur Petrol with 100% biomethane fuels
Vehicle specification
Tailpipe emissions (g/km)
Kerb
wt
Metric Mpg
Comb Comb CO2
CO
HC
NOx
Fuel Type
ULSP
42.2
159
0.547 0.072 0.050
1260 6.7
MSW BASE
58.6
122
0.547 0.072 0.025
1260 4.8
Sewage BASE 1260
4.8
58.6
122
0.547 0.072 0.025
Landfill BASE
58.6
122
0.547 0.072 0.025
1260 4.8
MSW CHP
58.6
122
0.547 0.072 0.025
1260 4.8
Sewage CHP
58.6
122
0.547 0.072 0.025
1260 4.8
Landfill LIQ
58.6
122
0.547 0.072 0.025
1260 4.8
Base vehicle: Ford Focus 1.6 Duratec (100PS) Manual 5-speed [2008]
Final Report
Page 20
PMs
0.000
0.000
0.000
0.000
0.000
0.000
0.000
Lifecycle emissions (g/km)
PMs
0.017
0.045
0.045
0.020
0.012
0.011
0.011
NOx
0.198
1.370
1.351
0.425
0.116
0.080
0.080
CO
0.678
0.912
0.909
0.734
0.675
0.669
0.669
HC
0.637
1.221
1.220
0.435
0.146
0.143
0.143
August 2008
SO2
0.225
0.116
0.116
0.116
0.116
0.116
0.116
CO2eq
210
115
101
105
77
55
87
Impact Rating
CH4
0.057
0.099
0.099
0.099
0.099
0.099
0.099
N2O
0.005
0.005
0.005
0.005
0.005
0.005
0.005
AQ
25
58
58
23
10
9
9
GHG
57
32
28
43
22
16
24
ALL
44
43
40
34
17
13
18
LCA of Road Transport Biofuels
5.1.
Fuel cycle results
As shown in Figure 6, all the biofuels considered by this report show a clear fuel cycle GHG
benefits as compared to conventional fossil-based vehicle fuels.
As compared to a ULSD baseline 100% biodiesel (B100) leads to a reduction in total fuel cycle
greenhouse gas emissions (expressed as grams CO2eq/km) of 36% (RME), 47% (PME) and
85% (UCO). These figures confirm the RFA findings expressed on a per GJ delivered basis (as
detailed in Section 3). The GHG benefits for lower percentage blends are proportionately
reduced, the benefit scaling directly with the percentage of the biofuel blend.
As compared to a ULSP baseline 85% bioethanol (E85) leads to a reduction in total fuel cycle
greenhouse gas emissions (expressed as grams CO2eq/km) of 26% (sourced from wheat), 39%
(sugar beet) and 68% (sugar cane). These figures confirm the RFA findings expressed on a per
GJ delivered basis.
As compared to a ULSP baseline 100% biomethane leads to a reduction in total fuel cycle
greenhouse gas emissions (expressed as grams CO2eq/km) of 51% (MSW BASE), 56% (Landfill
BASE), 59% (Sewage BASE), 66% (Landfill LIQ), 71% (MSW CHP), and 83% (Sewage CHP).
These figures confirm the RFA findings expressed on a per GJ delivered basis.
Figure 6 Life-cycle GHG emissions for selected biofuels and petrol/diesel
Lifecycle CO2eq emissions for Ford Focus (g/km)
200
180
160
140
120
100
80
60
40
20
0
In contrast to the fuel cycle greenhouse gas comparisons, summarising the changes in regulated
pollutants over the total fuel cycle for the biofuels analysed in not as straightforward. In most
cases, whereas some pollutants are reduced, others are increased over the fuel cycle. Without
further analysis, no clear picture emerges for any one particular biofuel or any biofuel type. For
this reason, this study uses an update version of the Cleaner Drive (external costing)
methodology to assess the overall impacts on air quality of biofuel use.
Final Report
Page 21
August 2008
LCA of Road Transport Biofuels
5.2.
Cleaner Drive analysis
In addition to making emissions comparisons for each of the vehicle types considered, this study
23
adopts the same approach as a previous report conducted for Camden and goes beyond an
inventory phase and includes an impact assessment as part of the life cycle emission
methodology. This is achieved by the use of the Environmental Rating Tool developed by the
European Cleaner Drive Programme.
This rating system uses recognised ‘external costs’ to establish the relative weight to attach to
different emissions – the external costs are values expressed in monetary terms that reflect the
overall damage to the environment and to human health caused by emissions. Using the Cleaner
Drive system, the level of environmental impact is expressed as a score between 0-100 (for
greenhouse gases, regulated pollutants and total impact); the lower the score, the less the
24
environmental impact. The rating system also provides separate scores for greenhouse gas
(GHG) and air quality (AQ) impacts. The GHG and AQ components can then be used to plot the
impact ratings on a two-dimensional impact chart.
The Cleaner Drive rating methodology uses a weighted index of carbon dioxide, methane, nitrous
oxide, oxides of nitrogen, hydrocarbons, carbon monoxide, particulate matter and sulphur dioxide
emissions associated with fuel use and production to produces the rating results. The
methodology has also been extended to include emissions associated with vehicle manufacture –
materials production and vehicle assembly. Using material profiles for different vehicle types
(petrol, diesel, LPG, hybrid, electric, etc), the mass of any particular vehicle car can be used to
25
estimate the emissions associated with vehicle manufacture and assembly. The Cleaner Drive
methodology used for this study therefore include both fuel and vehicle lifecycles.
The integration of fuel and vehicle life cycle emission using the Cleaner Drive rating system has
the advantage of simplifying the interpretation of results. This is because the comparison of
options is made complex due to the fact that each fuel type offers different global and local
emission benefits – for biofuels (and other alternative vehicle fuels), a reduction in one emission
may be accompanied by an increase in another pollutant.
Given the complexity of changes in lifecycle greenhouse gases and air pollutants already
identified in this report, the Cleaner Drive methodology (in its extended form) is therefore an ideal
tool with which to analysis the overall GHG and air quality impacts associated with each biofuel
option. Using the fuel cycle results already discussed in conjunction with the Cleaner Drive
methodology, the following results are generated – refer to Figures 7, 8 and 9.
Cleaner Drive results
As shown in Figure 7, the three biodiesel fuels analysed provide a clear greenhouse gas benefit
as compared to conventional ultra low sulphur diesel (ULSD). Adding an estimate of the
emissions associated with vehicle manufacture to the fuel cycle emissions, the results of this
analysis show a lifecycle reduction in greenhouse gases of 31%, 40% and 73% for RME, PME
and UCO respectively (based on the assumption described in earlier sections). These reductions
are significantly larger than the confidence limits indicted by the error bars shown in the charts.
23
Life Cycle Assessment of Vehicle Fuels and Technologies, 2006. URL:
http://www.travelfootprint.org/docs/Camden_LCA_Report_FINAL_10_03_2006.pdf.
24
Note that a reverse rating is used based on the Cleaner Drive score – this is simply the score subtracted
from 100 (ie New Cleaner Drive score = 100 – Original Cleaner Drive score). This results in cleaner vehicles
with lower emissions having a lower environmental rating.
25
See Life Cycle Assessment of Vehicle Fuels and Technologies report for more details.
Final Report
Page 22
August 2008
LCA of Road Transport Biofuels
For lifecycle air quality impact, the findings are less clear. For RME, three data points are shown
(MEET 1997, CSIRO 2000 and 2007) representing an increase in lifecycle air quality impact of
between 51% and 83%. For PME, the impact is approximately equivalent to the ULSD baseline
case, and for UCO fuels is reduced by 9%. However, due to the difficulty in sourcing upstream air
quality data, the level of confidence for air quality is less than for GHG impacts. As shown by the
larger horizontal error bars in Figure 7, the data suggests that the lifecycle air quality impact of
the three biodiesel fuels analysed is either broadly comparable, or is greater than is the case for
conventional diesel (ULSD) operation.
Figure 7 Cleaner Drive results for selected biodiesel fuels
Base vehicle: Ford Focus 2.0 TDCi (+DPF)
80
70
60
Lifecycle Greenhouse Impact
ULSD
50
RME100
(MEET97)
RME100
(CSIRO07)
RME100
(CSIRO00)
40
PME100
30
20
UCO100
10
0
0
10
20
30
40
50
60
70
80
Lifecycle Air Quality Impact
As shown in Figure 8, the two bioethanol fuels analysed provide a clear greenhouse gas benefit
as compared to conventional ultra low sulphur petrol (ULSP). Adding an estimate of the
emissions associated with vehicle manufacture to the fuel cycle emissions, the results of this
analysis show a lifecycle reduction in greenhouse gases of 23% and 54% for wheat and sugar
cane sourced fuels respectively (no Cleaner Drive data is available for sugar beet ethanol). These
reductions are significantly larger than the confidence limits indicted by the error bars shown in
the charts.
For lifecycle air quality impact, the findings are again less clear. For wheat sourced ethanol, the
central data point represents an increase in lifecycle air quality impact of 31%. For sugar cane
ethanol, the impact is reduced by 14%. However, due to the difficulty in sourcing upstream air
Final Report
Page 23
August 2008
LCA of Road Transport Biofuels
quality data, the level of confidence for air quality is less than for GHG impacts. Furthermore the
Cleaner Drive methodology takes no account of increased aldehyde emissions associated with
E85 use. This lower level of confidence is represented by the larger (and asymmetric) horizontal
error bars in Figure 7. Based on this analysis, a definitive comparison of the lifecycle air quality
impact with petrol operation is not possible – however, the likelihood is that the air quality impact
of the two bioethanol fuels analysed is either broadly comparable, or is greater than is the case
for conventional petrol (ULSP) operation.
Figure 8 Cleaner Drive results for selected bioethanol fuels
Base vehicle: Ford Focus 1.6 Duratec
80
70
Lifecycle Greenhouse Impact
60
ULSP
50
WHEAT-E85
40
30
SUGAR-E85
20
10
0
0
10
20
30
40
50
60
70
80
Lifecycle Air Quality Impact
As shown in Figure 9, the biomethane fuels analysed provide a clear greenhouse gas benefit as
compared to conventional ultra low sulphur petrol (ULSP). Adding an estimate of the emissions
associated with vehicle manufacture to the fuel cycle emissions, the results of this analysis show
a lifecycle reduction in greenhouse gases of between 44%, and 73%. These reductions are
significantly larger than the confidence limits indicted by the error bars shown in the charts.
For lifecycle air quality impact, the findings are also very clear, and form two distinctive groups.
For processes that depend on a high level of imported electricity biomethane from municipal or
sewage waste), lifecycle air quality impacts are significantly increased (by around a factor of 1.35.
In contrast, for methods that generate their own process energy (CHP), lifecycle air quality
impacts are significantly reduced by around 60%. These comparisons are larger than the
confidence limits indicted by the error bars shown in the charts.
Final Report
Page 24
August 2008
LCA of Road Transport Biofuels
Figure 9 Cleaner Drive results for selected biomethane fuels
Base vehicle: Ford Focus 1.6 Duratec
80
70
Lifecycle Greenhouse Impact
60
ULSP
50
40
MSW BASE
Sewage BASE
Landfill BASE
30
Landfill LIQ
20
MSW CHP
Sewage CHP
10
0
0
10
20
30
40
50
60
70
80
Lifecycle Air Quality Impact
Final Report
Page 25
August 2008
LCA of Road Transport Biofuels
6 Conclusions
This study as looked at the lifecycle GHG and air quality emissions for the three main biofuels
biodiesel, bioethanol and biomethane. For each fuel a range of feedstocks and production
pathways were assessed. The key conclusions of this analysis are:
LCA GHG emissions



Assuming that there are no direct or indirect land-use change effects all the biofuels will
have lower GHG emissions than fossil petrol or diesel;
Biodiesel from used cooking oil, along with biomethane from sewage and waste (using a
CHP system for process power), give the greatest GHG savings of up to 85%. These
fuels, being derived from waste products, are also not affected by land use impact
considerations.
The UK sourced liquid biofuels, RME, wheat ethanol and sugar beet ethanol perform
worse that imported fuels such as PME and sugar cane ethanol. All these fuels could
also be effected by land use change impacts of suitable controls are not in place.
LCA air quality impacts.



Overall the air quality impacts are much more varied and complicated to unravel, also the
data is a lot less robust.
Tail emissions are likely to have little direct impact on air quality, especially in low blends.
The main findings for each of the fuels are as follows:
o Biodiesel reduces HC, CO and PM, and may have a slight NOx penalty;
o Ethanol is broadly similar to petrol, but has a disbenefit in terms of high aldehyde
emissions;
o Biomethane is the cleanest burning fuel, but can have increase methane
emissions is poorly optimised catalysts are used.
The indirect or ‘up steam’ emissions in several cases have a much more significant
impact on the overall analysis than tail pipe emissions, but will not be emitted at point of
use. The main impacts are as follows:
o Upstream emissions for RME and wheat ethanol are quite high due to the
agricultural processes, giving a total air quality rating that is worse that diesel or
petrol;
o Emissions associated with imported electricity use in biomethane production and
upgrading are also high.
Integrated Cleaner Drive analysis
Trying to balance both of these aspects is difficult and as described in Section 5.2 has been
carried out with the Cleaner Drive methodology, which rates both GHG and air quality impacts as
shown in Figures 7 to 9. It also provides a single overall rating, which is shown for main fuels
assessed in Figure 10 below.
This shows that all the biofuels provide overall environmental benefits compared to petrol and
diesel, except biomethane produced using imported electricity. The benefits are also relatively
small for RME and wheat ethanol. The clear winners in this are biodiesel from used cooking oil;
and biomethane from waste, sewage or landfill using CHP for process energy. The
environmental credentials of these fuels are strengthened further as they are not affected by
potential land use change and other indirect effects associated with crop based fuels such as
biodiesel and bioethanol.
Final Report
Page 26
August 2008
LCA of Road Transport Biofuels
Figure 10 Combined Cleaner Drive rating for selected biofuels and petrol and diesel
50
45
Cleaner Drive rating
40
35
30
25
20
15
10
5
0
Final Report
Page 27
August 2008