Sustainable vehicle technologies : Driving the green agenda

Sustainable Vehicle Technologies:

Driving the Green Agenda

Automobile Division Organising Committee

Richard Folkson (Chairman) Consultant

Lisa Bingley MIRA

Chris Brace University of Bath

George Haritos University of Hertfordshire

Jon Hilton Flybrid Systems

James Marco Cranfield University

Mike Richardson Jaguar Land Rover

Mark Stanton Jaguar Land Rover

Chris Wheelans

Sustainable Vehicle Technologies:

Driving the Green Agenda

14–15 NOVEMBER 2012

GAYDON, WARWICKSHIRE

Oxford Cambridge Philadelphia New Delhi

Published by Woodhead Publishing Limited

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Library of Congress Control Number: 2012950277

ISBN 978 0 85709 456 8 (print)

ISBN 978 0 85709 457 5 (online)

Cover image courtesy of Jaguar Land Rover.

Produced from electronic copy supplied by authors.

Printed in the UK by 4edge Ltd, Hockley, Essex.

CONTENTS

LCA

C1324/014 Energy demand assessment of electrified drivetrains in 3

material extraction and system manufacturing

C-S Ernst, M Hans, L Eckstein, RWTH Aachen University,

Germany

C1324/018 Evaluating and prioritising sustainable vehicle technologies: 13

compliance, competition, conservation and context

I H Ellison, Jaguar Land Rover, UK

C1324/035 A life cycle assessment comparison of rapeseed biodiesel 23

and conventional diesel

M Stow, M C McManus, C Bannister, University of Bath, UK

C1324/032 Improving the sustainability of aluminium sheet 35

A Tautscher, Jaguar Land Rover, UK

C1324/038 Advanced phase powertrain design attribute and technology 47

value mapping

A Georgiou, Ford Motor Company; G Haritos, University of

Hertfordshire, UK

FUELS

C1324/013 Ammonia as a hydrogen energy carrier and its application 61

to internal combustion engines

M Koike, H Miyagawa, T Suzuoki, K Ogasawara,

Toyota Central R&D Labs., Inc., Japan

C1324/026 Evolutionary decarbonization of transport: a contiguous 71

roadmap to affordable mobility using sustainable organic

fuels for transport

J W G Turner, R J Pearson, Lotus Engineering; P Harrison,

A Marmont, R Jennings, Air Fuel Synthesis Ltd, UK;

S Verhelst, J Vancoillie, L Sileghem, Ghent University;

M Pecqueur, K Martens, Karel de Grote University College,

Belgium; P P Edwards, University of Oxford, UK

C1324/028 High pressure grid CNG: the low CO2 option for HGVs 89

J Baldwin, R M McKeon, CNG Services Ltd, UK

C1324/030 Materials handling vehicles; an early market sector for 99

hydrogen fuel cells within Europe

I Mansouri, R K Calay, University of Hertfordshire, UK

DUTY CYCLE

C1324/022 Electric vehicle efficiency mapping 113

S Carroll, C Walsh, Loughborough University; C Bingham,

University of Lincoln; R Chen, M Lintern, Loughborough

University, UK

C1324/037 Dependence on technology, drivers, roads, and congestion 123

of real-world vehicle fuel consumption

N E Ligterink, T C Kraan, A R A Eijk, TNO, Delft,

The Netherlands

ENERGY USAGE REDUCTION

C1324/006 The environmental case for bespoke double deck trailers 137

L A Curtis, Gray & Adams Ltd, UK

C1324/015 Aerodynamic drag reduction for low carbon vehicles 145

J P Howell, Tata Motors European Technical Centre, UK

C1324/025 Vehicle light weighting using a new CAE tool for predicting 155

thin film defects in high strength castings

M A Buckley, Jaguar Land Rover; N J Humphreys,

University of Birmingham, UK

C1324/024 Vehicle optimisation for regenerative brake energy 165

maximisation

M T Von Srbik, R F Martinez-Botas, Imperial College

London, UK

PROPULSION (ENERGY EFFICIENCY)

C1324/004 Direct heat recovery from the ICE exhaust gas 177

R Cipollone, D Di Battista, A Gualtieri, University of

L’Aquila, Italy

C1324/020 HyBoost – An intelligently electrified optimised downsized 189

gasoline engine concept

J King, M Heaney, E Bower, N Jackson, Ricardo;

J Saward, A Fraser, Ford Motor Company; G Morris,

P Bloore, Controlled Power Technologies, UK;

T Cheng, J Borges-Alejo, M Criddle, Valeo, France

PROPULSION

C1324/002 Development of a range extended electric vehicle 205

demonstrator

M D Bassett, J Hall, T Cains, G Taylor, M Warth, MAHLE

Powertrain Ltd, UK; C Vogler, Dresden University of

Technology, Germany

C1324/027 Modelling and simulation of a fuel cell powered medium 215

duty vehicle platform

R Felix Moreno, J T Economou, K Knowles, Cranfield

University, UK

C1324/033 Auxiliary power units for range extended electric vehicles 225

N Powell, M Little, J Reeve, J Baxter, Ricardo UK Ltd;

S Robinson, A Herbert, Jaguar Land Rover; A Mason,

P Strange, Tata Motors European Technical Centre;

D Charters, MIRA Ltd; S Benjamin, S Aleksandrova,

Coventry University, UK

AUTHOR INDEX

_______________________________________

© The author(s) and/or their employer(s), 2012

A life cycle assessment comparison of

rapeseed biodiesel and conventional diesel

M Stow 1, M C McManus 1, C Bannister 2

1 Sustainable Energy Research Team

2 Powertrain and Vehicle Research Centre

Department of Mechanical Engineering, University of Bath, UK

1 ABSTRACT

Biodiesel is often considered to improve energy security and reduce the impact of

fuel on climate change. However there are concerns about the impact of biodiesel

when its life cycle is considered. The potential impact of using biodiesel rather than

conventional diesel was investigated using a life cycle assessment (LCA) of

rapeseed biodiesel. Biodiesel leads to reduced fossil fuel use and is likely to reduce

the impact of transport on climate change. However it was found that the impact of

biodiesel towards other categories, i.e. land use and respiratory inorganics, was

greater than petroleum diesel. Therefore biodiesel production should be carefully

managed to mitigate its impact on the environment.

Keywords: Life Cycle Assessment; Biodiesel; Rapeseed

2 BACKGROUND

Biodiesel is considered to have a number of advantages over diesel. Biodiesel can

be produced from an array of feedstocks and, unlike diesel, feedstock sources are

highly distributed around the world. This means that an increase in biodiesel use

should lead to an increase in energy security(1). Biodiesel is often thought,

incorrectly, to be carbon neutral on the basis that any carbon released during

combustion had previously been absorbed from the atmosphere during crop

growth(2). Biodiesel is compatible with diesel. Blends of biodiesel and diesel are

labelled Bη, where η is the proportion of biodiesel as a percentage. They can be

blended together in any proportion, the same distribution infrastructure can be

used and at low blend levels, used in diesel engines with no modification(3). These

apparent advantages have led to legislation being introduced to increase the use of

biofuels(4). The European parliament has set a target that 10% of fossil fuel

consumption for transportation must be replaced by biofuels by 2020 in all Member

States(5).

However, there are concerns about biodiesel’s sustainability(4). The impact

biodiesel has on land use change, both direct and indirect, is of major interest(1).

Previous biodiesel LCAs have highlighted the agricultural stage to have a large

effect on the impact of biodiesel, due mainly to the nitrogen fertiliser used(6).

There is consensus that tailpipe emissions of NOx increase with biodiesel(7) and

evidence that CO also increases(8). Due to these concerns, a LCA was carried out

to investigate the environmental impact of the production and use of biodiesel in

the UK using rapeseed as a feedstock.

23

3 INTRODUCTION TO LCA

The impact of a product on the environment can be investigated using LCA, as

shown in Figure 1(9). LCA examines the environmental impact of a product or

system over a range of environmental issues, such as greenhouse gases, fossil fuel

use, and ozone depleting substances etc. LCA is analysed in terms of a functional

unit, chosen because it reflects the function of the product. This allows comparison

between products fulfilling the same function. When comparing multiple products, it

is unlikely that one will perform better than another in all impact categories

investigated. Thus, which product is considered to have the smallest overall impact

on the environment will be decided based on the value the assessor places on each

individual category.

Figure 1 LCA methodology: adapted from ISO 14040: 2006(9)

In processes where more than one product is produced, the inventory should be

apportioned between the co-products. According to a hierarchy set out in ISO

14044:2006 the first option is system expansion to include processes relating to

the co-product. If this is not suitable, then the inputs and outputs should be

partitioned between the co-products in a ratio which reflects some physical property

of the products, this is the burden of that product(10).

4 LCA OF BIODIESEL

Figure 2 Rapeseed biodiesel production and use

24

Data to model the lifecycle of rapeseed biodiesel was obtained from published

literature, which matched the data quality requirements, and used to build an

inventory. This inventory was modelled in SimaPro 7(11), primarily using the

Ecoinvent database, which contains inventory data for many materials and

processes. The inventory was analysed using the Eco-indicator 99H impact

assessment method. The diesel LCA was modelled using the same method.

Table 1 Inventory of B100 for 1km with a fuel consumption of 68g

Inputs Amount Output Amount

Nature Emissions to air

Carbon Dioxide 353.7 g Hexane 0.0065 g

Arable land 0.25 m2

Carbon Monoxide 0.91 g

Technosphere Carbon Dioxide 43.2 g

Methanol 10.2 g Nitrogen Oxide (NOx) 0.65 g

Pesticide 0.23 g Nitrous Oxide 0.45 g

Potassium Hydroxide 0.60 g Methane 0.11 g

Ploughing 0.49 m2

Ammonia 0.50 g

Transport 0.068 tkm Hydrocarbons 0.055 g

Sowing 0.49 m2

Particulates 0.037 g

Nitrogen fertiliser 9.1 g Emissions to water

Fertilising 0.49 m2

Nitrate 2.50 g

Phosphorous fertiliser 0.98 g Phosphorus 0.017 g

Application of pesticides 3.4 m2

Potassium 0.98 g

Potash 1.2 g Emissions to soil

Combine harvesting 0.49 m2

Methane 0.032 g

Sulphur 3.9 g

Lime 0.16 kg

Electricity 0.023 kWh

Heat 0.20 MJ

4.1 Goal and scope

The purpose of this LCA was to investigate how a transition towards biodiesel might

affect the impact of transportation by comparing it to a diesel LCA. It was also used

to investigate the potential for reducing this impact, by identifying which processes

contributed significantly and then to model alternative methods of production.

Rapeseed biodiesel was considered to be a transportation fuel in this LCA. To allow

a comparison between the biodiesel LCA and the diesel LCA, the functional unit was

1km of distance travelled.

During biodiesel production (See Figure 2 for details of production method, inputs

and outputs), three co-products are formed: straw, meal cake (what remains of the

seed after oil extraction) and glycerol(12). Although system expansion is the

preferred method of burden allocation(10), this would increase the uncertainty in

the result as it is not clear what product the co-products would offset(13).

Therefore, burdens were partitioned proportionally, according to the desired

characteristic of the co-product, as outlined below.

25

Rapeseed straw is generally not harvested, consequently no burdens were allocated

to straw(14). However, studies have shown that leaving straw in situ reduces soil

carbon emissions: this was reflected in the inventory(6). Meal cake is commonly

used as a feed for livestock and so burdens were allocated according to energy

content(13). Burdens were allocated by mass for glycerol, as it can be used as a

feedstock for a wide range of products(15).

Due to the controversy surrounding allocation methods(16), a sensitivity analysis

was undertaken. The outcome of the LCA is dependent on the allocation method:

using mass allocation, biodiesel has a lower impact than diesel, whereas using the

allocation method in this LCA, the impact of biodiesel is higher.

4.2 Inventory

The inventory of inputs and outputs to travel 1km using B100 is presented in Table

1. The inventory is not exhaustive, however, the principal substances and

processes contributing to the impact are included. The biodiesel production

inventory was built up using data from multiple sources(6, 12, 14, 17-23). This was

then combined with data on biodiesel use to create inventories for biodiesel blends

up to B50(8). It was assumed that the linear relationships reported on fuels up to

B50 would remain true for B100.

5 RESULTS AND DISCUSSION

5.1 Comparison of biodiesel and diesel

Table 2 shows the embodied energy and global warming potential of diesel and

biodiesel. The impact transportation has on climate change is likely to be reduced

by switching to biodiesel. Although the process of producing and using biodiesel

emits greenhouse gases, much of the carbon dioxide from the fuel has been

absorbed during growth. However, fossil fuels are also used during processing and

transport and so the fuel is not “carbon neutral”. The extent of the impact that

biodiesel has on climate change has a high level of uncertainty attached to it as

agricultural carbon cycles are difficult to model accurately. Soil carbon emissions

are linked to prior land use(24) and in countries where crop rotations are common,

they can’t be associated with a particular crop(6). Therefore the result presented

here is only applicable to biodiesel produced from existing arable land and further

work is required to investigate the uncertainty and impact of land use change.

Table 2 Embodied energy and GWP100 data for diesel and biodiesel per km

Figure 3 shows the impact of a person using a vehicle for a year, as a proportion of

their total annual impact, for different biodiesel blends. As the amount of biodiesel

in the blend increases, resource use falls, due to a reduction in fossil fuel use. By

reducing the reliance of the transportation system on diesel, energy security in the

UK has the potential to improve, as biodiesel feedstocks are a widely distributed

commodity. However the use of biodiesel does not end reliance on fossil fuels, as

natural gas is used as a feedstock for the methanol and ammonium nitrate

fertilisers used in its production.

Although resource use decreases, the impact on the eco system increases. The

overall impact on human health does not significantly change, because whilst some

categories increase, others decrease.

Category Units Diesel Biodiesel

Cumulative Energy Demand MJ equivalent 3.16 -1.24

Global Warming Potential 100 kg CO2 equivalent 0.0301 -0.0488

26

Land use is the main driver behind the impact on the eco system and is likely to be

the primary problem encountered with an increase in biodiesel adoption. Issues

surrounding the use of land for biodiesel feedstock production are complex:

displacement of food crops, land conversion & loss of biodiversity. Any increase in

crops grown for biofuels will have to be carefully managed to prevent these issues

becoming more problematic than the diesel they replace. For example, if legislation

means that biofuels are required to come from a variety of feedstocks, the impact

on biodiversity could be reduced. However if there is a large increase in the amount

of farmed land due to government targets, then problems associated with farming,

such as eutrophication (an excess of nutrients in waterways), would increase(1, 3,

17).

Figure 3 The comparative impact of different fuel blends, when used to

drive the annual average distance(25), as a proportion of an average

European citizen’s total annual impact

5.2 Impact of biodiesel

Figure 4 shows how the three stages of biodiesel production, rapeseed growth, oil

extraction and transesterification (a process which alters the viscosity to more

closely match that of diesel) and the stage of biodiesel use contribute to biodiesel’s

impact. Growing rapeseed has a significant contribution across all categories

whereas oil extraction has only a small contribution. Transesterification and

biodiesel use have substantial contributions in a few categories such as fossil fuel

use and respiratory inorganics.

Production of ammonium nitrate fertiliser, soil emissions and land use were found

to be mainly responsible for the impact attributed to rapeseed growth. Ammonium

nitrate fertiliser is produced using natural gas as a feedstock and the process

produces chemicals which are potentially harmful to the ecosystem. There is

evidence that excess fertiliser is often applied to crops and that this causes

significant damage due to nitrogen associated pollution(26).Leaving the straw in

the field, can improve the soil quality, which may reduce the amount of fertiliser it

is necessary to use(27). This indicates that straw should not be considered to be a

waste product. Soil emissions can lead to an increase in the quantity of toxic

substances in the ecosystem, climate change and eutrophication, and are linked to

soil quality and fertiliser application(6).

Transportation from the field to the biodiesel plant by road is the main cause for the

impacts of oil extraction. The fuel used by lorries (and tractors) was modelled as

diesel. As the proportion of biodiesel used increases, the impacts from

transportation will change, although because it only accounts for a small portion of

the overall impact of biodiesel the main findings of this LCA are unlikely to be

significantly different.

Methanol is used as a reactant in the transesterification process, which reduces the

viscosity of the oil, to create rapeseed methyl ester (RME biodiesel). The most

0

5

10

15

20

25

30

0 10 20 30 40 50 60 70 80 90 100

Impact as a

proportion of the

total annual impact

of a European citizen

%

Amount of Biodiesel %

Resource Use

Eco System

Human Health

27

common feedstock for methanol production is natural gas. This, along with the

transport cost of distributing the biodiesel, accounts for most of the contribution

this stage has on fossil fuel use.

Figure 4 Each processes contribution towards the total impact of biodiesel

A number of studies have measured the emissions from an engine running on

biodiesel and reported reductions in CO, hydrocarbons and particulate matter but

an increase in NOx and fuel consumption(7). However in a study using a modern

2.0 litre common rail diesel engine examining emissions post catalyst, CO

emissions were found to rise, due to a decrease in catalyst conversion efficiency(8)

caused by a reduction in exhaust gas temperature when using biodiesel blends.

This study was used because post catalyst emissions are most relevant to the

environment. NOx emissions are known to cause photochemical smog and lead to

the production of tropospheric ozone, both of which can have adverse effects when

inhaled. Similarly, hydrocarbon and particulate emissions can lead to smog and

contain carcinogenic compounds leading to respiratory diseases and cancer(28).

Vehicle emissions of nitrogen oxides, hydrocarbons and particulates account for a

large portion of the impact on respiratory effects. It should be noted that further

aftertreatment systems, such as NOx traps and particulate filters, can be employed

to significantly reduce NOx and particulate emissions respectively, thus mitigating

the impact of transport on respiratory effects.

Whilst switching to biodiesel appears to reduce the impact of transportation on

global environmental issues, such as climate change and depleting resources,

localised environmental issues, such as eutrophication of waterways and respiratory

problems are likely to increase. However as a large proportion of the impact of

biodiesel can be attributed to producing the crop, these localised environmental

issues won’t necessarily be felt in the same area as the biodiesel is used. This is

-80%

-60%

-40%

-20%

0%

20%

40%

60%

80%

100%

Carcinogens

Resp. organics

Resp. inorganics

Climate change

Radiation

Ozone layer

Ecotoxicity

Land use

Minerals

Fossil fuels

Rapeseed Growth Oil Extraction

Transesterification Vehicle Emissions Acidification Eutrophication

28

due to the potential for direct and indirect land use change, for example, food crop

displacement. Hence transportation will continue to impact at a global scale.

5.3 Reducing the impact of biodiesel

Three aspects of biodiesel production and use: fertiliser, methanol and vehicle

emissions were found to contribute significantly to the impact categories

investigated. Therefore these aspects were investigated further to see if their

impact could be reduced.

Figure 5shows how the changes made in each of the three scenarios affected the

impact of biodiesel when compared to the standard scenario. A fourth scenario was

set up to investigate the impact of biodiesel when all three of the alternative

scenarios were combined.

Figure 5 Comparing the scenarios with respect to the standard case

5.3.1 Fertiliser scenario

Due to the high impact ammonium nitrate fertiliser has on the environment, the

use of an alternative fertiliser, meal cake, was investigated. Meal cake is a co￾product formed during the oil extraction process, which is commonly used as

animal feed, but can also be used as a fertiliser. The amount of meal cake applied

was calculated to maintain the level of macronutrients the crop received.

Overall, the impact of rapeseed biodiesel was improved by using the alternative

fertiliser, meal cake. Climate change impacts improve significantly. This is due to

the larger amount of rapeseed crop modelled within the system, which is used to

produce the meal cake. However land use increases with this change in fertiliser

which has already been identified as a major issue with biodiesel use.

5.3.2 Transesterification alcohol scenario

The use of methanol produced from natural gas in the transesterification process is

a significant contribution towards fossil fuel use. Since a major driver for biofuels is

for a reduction in fossil fuel use, the impact of substituting methanol produced from

biomass was investigated.

-60%

-20%

20%

60%

100%

140%

180%

220%

Carcinogens

Resp. organics

Resp. inorganics

Climate change

Radiation

Ozone layer

Ecotoxicity

Land use

Minerals

Fossil fuels

Improvement %

Fertiliser scenario

Transesterification alcohol scenario

Engine timing scenario

Combined scenario Acidification Eutrophication

29

As expected, this change reduced fossil fuel use, impact on the ozone layer and

contribution towards climate change. The effect on climate change is likely to be

due to the increase in crops within the system rather than an actual reduction.

However this change worsens the impact of biodiesel across all other categories. As

access to agricultural land for biofuels is likely to become an increasing problem as

production increases other ways of reducing the impact of methanol should be

investigated in future studies. It has been shown that if ethanol is used, the

resulting biodiesel produces lower exhaust emissions which could potentially lower

the life cycle impacts of biodiesel(29).

5.3.3 Engine timing scenario

Studies have shown that emissions can be reduced by optimising the engine

operation, by adjusting fuel injection timing, to run on biodiesel(30). The scenario

presented here is a theoretical scenario based on this study as exact reductions in

tailpipe emissions were not available. It is included to investigate how changes

would affect the LCA of biodiesel. Figure 6 shows measured tailpipe emissions

comparing biodiesel and diesel, with the bar indicating the theoretical potential for

reductions in biodiesel emissions with engine timing optimisation. In the theoretical

engine timing optimisation, fuel consumption is reduced by 4g/km.

This change leads to an improvement in all categories with the exception of climate

change. These small changes can be attributed to the reduction in fuel

consumption, and the corresponding reduction in rapeseed crop produced. Vehicle

emissions of compounds which cause respiratory problems such as NOx and

particulates were also reduced. This would be particularly beneficial for urban

environments.

Optimising the engine to reduce fuel consumption is desirable to reduce the impact

of biodiesel. However, during this transitional period it is unlikely that engines could

be optimised correctly as the diesel standard, EN590, currently allows the addition

of up to 7% biodiesel with no additional labelling(31). Furthermore part of the

appeal of biodiesel is that it can be used in unmodified cars.

Figure 6 Biodiesel emissions compared with diesel showing the potential

reduction in emissions due to engine timing optimisation

5.3.4 Combined scenario

A scenario which combined the fertiliser, transesterification alcohol and engine

timing scenarios was used to investigate how multiple changes affected the life

cycle. Although some of the individual changes worsened the impact of biodiesel in

some categories, when combined together, all categories (with the exception of

radiation and land use) show an improvement over the standard biodiesel scenario.

Results from the current LCA indicate that there are ways in which the impact of

biodiesel on the environment can be reduced. However these improvements are not

always clear cut; they reduce impacts in one area, whilst increasing those in

another. Therefore whether or not they are considered improvements will depend

on the value judgment of the assessor.

0

0.2

0.4

0.6

0.8

1

CO NOx Hydrocarbons Particulates

Emissions g/km

Biodiesel Diesel t

30