Alternative fuels : expert group report.
Date: 2018-01-23
Institutions: Directorate-General for Research and Innovation
Subjects: energy efficiency, energy research, reduction of gas emissions, renewable energy, research and development, substitute fuel

Alternative Fuels 

Expert group report 

Studies and reports

EUR KI-02-17-940-EN-N 

 
 
 
 
 
 
 
 
 
 
 
EUROPEAN COMMISSION 

Directorate-General for Research and Innovation 
Directorate H — Transport 
Unit H.1— Transport strategy 

Contact: Roberta Zobbi 

E-mail:  Roberta.Zobbi@ec.europa.eu  

RTD-PUBLICATIONS@ec.europa.eu 

European Commission 
B-1049 Brussels 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
EUROPEAN COMMISSION 

Alternative Fuels 

Expert group report 

prepared by Ausilio Bauen, Inmaculada Gomez, Dave OudeNijeweme, 
Maria Paraschiv 

Legal notice: The views expressed in this report, as well as the 
information included in it, do not necessarily reflect the opinion or position 
of the European Commission and in no way commit the institution. 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Directorate-General for Research and Innovation 
Smart, Green and Integrated Transport  

EUR KI-02-17-940-EN-N 

 
 
 
 
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ISBN 978-92-79-71857-1 

doi: 10.2777/741279 

KI-02-17-940-EN-N 

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Cover images: © Lonely, # 46246900, 2011. © ag visuell #16440826, 2011. © Sean Gladwell #6018533, 2011. 
© LwRedStorm, #3348265. 2011. © kras99, #43746830, 2012. Source: Fotolia.com 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Contents 

1 

Introduction .......................................................................................................................................... 3 

1.1 

1.2 

1.3 

1.4 

Context for the STRIAs .................................................................................................................. 3 

Transport energy and alternative fuels use ................................................................................. 3 

The case for alternative fuels in transport ................................................................................... 6 

GHG emissions savings from alternative fuels in the EU 28......................................................... 8 

2  Objective, scope and approach of the STRIA on Alternative Fuels end-use ...................................... 10 

2.1 

2.2 

Scope .......................................................................................................................................... 10 

Approach .................................................................................................................................... 12 

3 

State of the art on alternative fuel end-use ....................................................................................... 12 

3.1 

3.2 

3.3 

Light Duty Vehicles ..................................................................................................................... 14 

Heavy Duty Vehicles ................................................................................................................... 20 

Rail .............................................................................................................................................. 26 

3.4  Waterborne transport ................................................................................................................ 27 

3.5 

3.6 

Aviation....................................................................................................................................... 33 

Summary of trends in alternative fuel R&I ................................................................................. 38 

3.6.1 

Methane-based fuels .......................................................................................................... 38 

3.6.2 

LPG ...................................................................................................................................... 39 

3.6.3 

Alcohols, esters and ethers ................................................................................................ 39 

3.6.4 

Synthetic Paraffinic Fuels ................................................................................................... 39 

4 

Potential benefits of alternative fuel use in different transport modes and engines ....................... 41 

4.1 

4.2 

4.3 

Alternative fuels effect on GHG and noxious emissions ............................................................ 41 

EU competitive position ............................................................................................................. 45 

Low carbon energy diversification ............................................................................................. 47 

4.3.1 

Renewable fuel availability ................................................................................................. 48 

5 

Research agenda ................................................................................................................................ 50 

5.1 

R&I needs ................................................................................................................................... 50 

5.1.1 

LDVs .................................................................................................................................... 50 

5.1.2 

HDVs ................................................................................................................................... 54 

5.1.3 

Rail ...................................................................................................................................... 59 

5.1.4  Waterborne ........................................................................................................................ 61 

5.1.5 

Aviation ............................................................................................................................... 64 

5.2 

5.3 

Implementation plan .................................................................................................................. 67 

Synthesis of R&I agenda ............................................................................................................. 68 

1 

 
 
5.3.1 

Roles and resources ............................................................................................................ 69 

References .......................................................................................................................................... 71 

Appendix ............................................................................................................................................. 74 

6 

7 

7.1 

7.2 

7.3 

Table of acronyms ...................................................................................................................... 74 

Technical glossary ....................................................................................................................... 75 

Impact of alternative fuel deployment and development ......................................................... 79 

7.3.1 

LDV ...................................................................................................................................... 81 

7.3.2 

HDV ..................................................................................................................................... 82 

7.3.3 

Rail ...................................................................................................................................... 83 

7.3.4  Waterborne transport ........................................................................................................ 84 

7.3.5 

Aviation ............................................................................................................................... 85 

7.4 

Stakeholders consulted .............................................................................................................. 87 

2 

 
 
 
 
 
1  Introduction 

1.1  Context for the STRIAs 
On 25 February 2015 the European Commission published the Communication “A Framework Strategy 
for  a  Resilient  Energy  Union  with  a  Forward-Looking  Climate  Change  Policy”  setting  a  framework  for 
achieving  the 2030 EU  climate  and energy goals1. The Energy Union vision provides  the  framework to 
respond  to  the  energy  challenges.  It  is  built  on  a  set  of  climate  and  energy  targets  to  be  realised  by 
2030:  at  least  40%  domestic  reduction of  greenhouse  gas emissions,  at  least  27%  share of  renewable 
energy consumed in the EU and at least 27% improvement in energy efficiency. Reaching and exceeding 
these intermediary objectives will allow the EU to pursue the goal of an 80-95% decrease in greenhouse 
gas emissions by 2050. 

The “Research, innovation and competitiveness” dimension of the Communication foresees the launch 
of  3  initiatives:  the  integrated  Strategic  Energy  Technology  Plan  (SET  Plan),  the  Strategic  Transport 
Research and Innovation Agenda (STRIA) and Global Technology and Innovation Leadership Initiative. 

The  STRIA will  contribute to the  realisation  of  the  Energy  Union  vision  by  identifying  the contribution 
that the transport sector can make to the achievement of the climate and energy goals and providing 
input  for  research  and  innovation  policy  to  maximise  the  impact  of  low-carbon  technology  solutions. 
The exercise is carried out jointly by RTD/H and MOVE/C, and will feed into the Communication on the 
R&I and competitiveness component of the Energy Union in November 2016. STRIAs will be developed 
for  7  key  transport 
innovation  areas:  Electromobility,  Alternative  fuels,  Vehicle  design  and 
manufacturing, Connectivity and automation of transport, Transport infrastructure, Network and traffic 
management systems, Smart transport and mobility services (incl. urban). The STRIAs identify R&I that 
will speed up technological changes in transport and better target public and private investments in the 
transport  sector  to  tackle  technical  and  non-technical  challenges  to  meeting  energy  and  climate 
objectives of the Energy Union and beyond to 2050. 

The  recent  European  Communication  of  20  July  2016  on  “A  European  Strategy  for  Low-Emission 
Mobility”  also  stresses  the  need  to  develop  and  deploy  alternative  low  carbon  energy  options  in 
transport,  including  gaseous  and  liquid  fuels,  and  the  need  for  research  and  innovation  that  brings 
together  three  interconnected  strands:  energy  technologies,  transport  and  industry,  through  an 
Integrated Research, Innovation and Competitiveness Strategy for the Energy Union.  

1.2  Transport energy and alternative fuels use 
In  2014  the  EU  28  transport  sector  consumed  353  Mtoe,  which  accounted  for  33%  of  total  energy 
consumption  (Figure  1).    This  figure  does  not  include  the  fuel  stored  in  maritime  bunkers  in  Europe, 
which would bring the total energy consumed to 398 Mtoe. Out of this amount, the largest consumer is 
road  traffic  (73.7%),  followed  by  aviation  (12.6%),  maritime  (10.6%),  rail  (1.6%)  and  inland  navigation 
(1.1%)  (shown  in  Figure  2  and  Figure  3).  Oil  products  supplied  94%  of  the  energy  demand  from 
transport, 86% of which was imported from outside the EU. 

1 Com (2015) 80 final 

3 

 
 
                                                           
Final Energy Consumption by sector in 2014 (EU28) 

Non-specified, 0.5% 

Industry, 25.9% 

Transport, 33.3% 

Agriculture and 
Forestry, 2.2% 

Services, 13.3% 

Residential, 24.8% 

Figure 1 - Final Energy Consumption by sector (EU28). Source: Eurostat 

Share of transport energy demand by source in 2014 (EU28) 

Kerosene 
14% 

Diesel 
55% 

Gasoline 
22% 

LPG 
2% 

Electricity 
2% 

Biofuels 
4% 

Natural gas 
1% 

Fuel Oil 
0% 

Figure 2 - Share of transport energy demand by source in 2012 (EU28). Source: Eurostat 

Share of transport energy demand by mode in 2014 (EU28) 
Rail 
1.6% 

Maritime 
10.6% 

Other 
0.4% 

Inland navigation 
1.1% 

Aviation 
12.6% 

Figure 3 - Share of transport energy demand by mode in 2012 (EU28). Source: Eurostat 

Road 
73.7% 

4 

 
 
 
 
 
The transport mode that is proportionally least dependent on fossil fuels is rail, with petroleum-based 
products accounting for 33% of energy consumption. The dominant alternative is electricity, with some 
biofuel consumption in the form of biodiesel. 

Road  transport  depended  on  oil  products  for  94%  of  its  energy  use  in  2014.  Alternatives  include 
biofuels,  electricity,  and  fossil  fuels  such  as  CNG,  LNG,  LPG  and  GTL,  only  some  of  which  have  some 
decarbonisation  potential.  On  a  total  cost  of  ownership  basis  (including  subsidies),  in  some  countries 
BEVs and PHEVs can already be more attractive than the incumbent internal combustion engine vehicle 
due to lower fuel cost and taxes, and purchase incentives. 

Petroleum-based products satisfied almost all of the energy demand in waterborne and air transport in 
2014.  Air  transport  is most  dependent  on  oil,  with  the  main  alternative  energy  source  being  biofuels. 
Alternatives in waterborne transport are very similar to those for long range heavy duty road transport. 

Transport  greenhouse  gas  emissions,  including  from  international  aviation  and  maritime  transport, 
increased  by  around  34%  between  1990  and  2008.  Over  the  same  period,  energy  industries  reduced 
their emissions by about 9%. Following the emission decline between 2008 and 2013 transport emission 
level in 2013 are 19,4% above 1990 levels2. The sector has been inherently difficult to decarbonise, and 
improvements  in  energy  efficiency  have  been  offset  by  increasing  transport  volumes  and  distances, 
while the take up of alternative fuels has so far been limited. Unless decisive action is taken, this trend is 
likely  to  continue  and  by  2030  transport  is  expected  to  become  the  main  source  of  GHG  emissions, 
surpassing the power sector3. This is largely due to the continued reliance of all transport modes on oil4. 
Based on current trends5, oil products are expected to cover 88% of the EU transport energy needs in 
2030 and 84% in 2050. Despite EU policies6 and related national support schemes intended to promote 
a wide range of renewable and low carbon energy sources in transport, only 6% of the energy used in 
transport was from renewable sources in 20147. 

Air  quality  also  remains  an  issue  for  all  transport  modes  (emissions  from  road  vehicles,  diesel 
locomotives, planes in airports and ships in harbours). As an illustration, it is estimated that one third of 
the  EU  citizens  live  in  urban  areas  with  pollution  levels  above  legal  thresholds  and  around      400,000 
premature  deaths  every  year  can  be  attributed  to  pollution,  where  road  transport  is  one  the  main 
contributors8 (40%).  

The 2011 EC White Paper on Transport9 requires a 60% reduction in transport GHG emissions by 2050 
(compared to 2005 levels), with specific targets for different transport modes, while at the same time 
drastically  reducing  other  negative  impacts  (accidents,  emissions/noise,  congestion)  and  achieving 

2 EEA, Greenhouse gas emissions from transport. Available at: 

http://www.eea.europa.eu/downloads/601c247f67b243478cdf5d8531ad2630/1468931809/transport-
emissions-of-greenhouse-gases-5.pdf  

3 EU energy, transport and GHG emissions. Trends to 2050 (link) 
4 94% of energy used in transport consists in oil products, 90% of which imported 
5 State of the Art on Alternative Fuels Transport Systems in the European Union (link) 
6 Renewable  energy  directive  (RED)  and  fuel  quality  directive  (FQD).  The  RED  mandates  the  use  of  10%  of 
renewable  sources  in  transport  to  be  achieved  by  2020.  The  FQD  introduces  a  6%  carbon  intensity  reduction 
target to be reached by 2020.  

7 EU energy, transport and GHG emissions. Trends to 2050 (link) 
8 European Environmental Agency: Air quality in Europe — 2014 report  
9 EC White Paper: Roadmap to a Single European Transport Area  – Towards a competitive and resource efficient 
transport system. Available at: http://eur-lex.europa.eu/legal-content/EN/ALL/?uri=CELEX%3A52011DC0144 

5 

 
 
                                                           
sustainable mobility services for citizens and transport services for businesses. The COP21 agreement is 
likely  to  require  even  greater  reductions,  up  to  100%  decarbonisation  by  2050  for  the  1.5°  scenario. 
Achieving  deep  GHG  emissions  savings  and  other  energy  and  environment  improvements  in  the 
transport  sector  will  require  a  holistic  approach  that  tackles  demand  for  transport  services,  more 
efficient technologies and alternative fuels.  

1.3  The case for alternative fuels in transport 
The  International  Energy  Agency’s  scenarios  in  its  World  Energy  Outlook10 and  Energy  Technologies 
Perspectives11 publications  illustrate  the  importance  of  alternative  fuels  in  achieving  GHG  emissions 
savings  in  transport,  in  conjunction  with  demand  and  efficiency  measures  (Figure  4).  An  important 
feature  of  the  scenarios  is  the  potential  relative  and  absolute  increase  in  importance  of  road,  air 
passenger travel and sea freight energy demand (Figure 5).   

Figure 4 - WTW emissions reductions from transport in 4DS and 2DS 

Figure 5 - Global energy consumption in transport by scenario 

Dependency on oil in the transport sector is high due to: high energy density; easy handling and existing 
infrastructure;  and  cost  competitiveness  compared  to  alternatives.  Globally,  in  a  business  as  usual 
scenario oil is expected to remain the dominant fuel in transport accounting for 85% of transport energy 
demand  in  2040  (New  Policies  Scenario  /  4DS),  emphasising  the  need  for  additional  action  to  reduce 
emissions in transport. Road transport would continue to account for around three quarters of transport 
oil demand. While aviation would be the fastest growing transport energy demand (expected to grow by 
50% until 2050), road transport would still account for two thirds of transport oil demand growth. But in 
OECD  countries  transport  oil  demand  would  decrease  in  all  sub-sectors  except  aviation.  As  freight 
transport  demand  is  expected  to  grow  faster  than  passenger  transport  demand,  diesel  would  surpass 

10 IEA (2015), World Energy Outlook, International Energy Agency, Paris 
11 IEA (2015), Energy Technologies Perspectives, International Energy Agency, Paris 

6 

 
 
 
 
                                                           
gasoline demand in the 2030s. But, such a scenario is not compatible with meeting future ambitions of 
mitigating climate change.  

Alternative fuel penetration in energy scenarios is largely driven by the need to reduce GHG emissions, 
but other forces may be at play too. For example, more stringent sulphur, NOx and PM limits concerning 
waterborne transport, are likely to lead to a switch from residual fuel oil to middle distillates together 
with exhaust treatments and ultimately much cleaner fuels such as LNG. The deployment of alternative 
energy in transport is expected to grow, representing roughly half of energy demand in 2050 (in a 2DS 
scenario). Reliance on liquid fuels however persists, leading to a high demand for alternative liquid fuels 
as a result (around one quarter of transport energy demand). 

The EU follows the general trends of OECD countries in the IEA scenarios12, as illustrated by Figure 6. In a 
reference scenario transport energy demand stays roughly constant out to 2050 with gasoline demand 
decreasing  substantially  as  a  result  of  efficiency  improvements  and  electrification  of  LDVs,  diesel 
demand stays roughly constant with efficiency gains offset by increased freight travel demand, aviation 
demand increases gradually. Alternative fuels play a role similar in size to that projected by the IEA (in 
the New Policies / 4DS scenario) for OECD countries across different transport modes. More ambitious 
GHG  emissions  reduction  targets  require  significant  further  improvements  in  reducing  demand  and  in 
using alternative fuels, with alternative fuels contributing over half of transport energy demand in such 
scenario. However, it is not possible to expect that all sectors can equally benefit from biofuels due to 
restrictions in available biomass. A later section in this report provides a brief review of the potential for 
biofuels and other alternative renewable fuels. 

12 IEA Scenarios:  

- The 2°C Scenario (2DS) is the main focus of Energy Technology Perspectives. The 2DS lays out an energy system deployment 
pathway and an emissions trajectory consistent with at least a 50% chance of limiting the average global temperature increase 
to 2°C. The 2DS limits the total remaining cumulative energy-related CO2 emissions between 2015 and 2100 to 1 000 GtCO2. 
The 2DS reduces CO2 emissions (including emissions from fuel combustion and process and feedstock emissions in industry) by 
almost 60% by 2050 (compared with 2013), with carbon emissions being projected to decline after 2050 until carbon neutrality 
is reached. 

- The 4°C Scenario (4DS) takes into account recent pledges by countries to limit emissions and improve energy efficiency, which 
help limit the long-term temperature increase to 4°C. In many respects the 4DS is already an ambitious scenario, requiring 
significant changes in policy and technologies. Moreover, capping the long-term temperature increase at 4°C requires 
significant additional cuts in emissions in the period after 2050. 

- The 6°C Scenario (6DS – reference scenario) is largely an extension of current trends. Primary energy demand and CO2 
emissions would grow by about 60% from 2013 to 2050, with about 1 700 GtCO2 of cumulative emissions. In the absence of 
efforts to stabilise the atmospheric concentration of GHGs, the average global temperature rise above pre-industrial levels is 
projected to reach almost 5.5°C in the long term and almost 4°C by the end of this century. 

Available at: https://www.iea.org/publications/scenariosandprojections/ 

7 

 
 
                                                           
 
 
Figure  6  -  Final  energy  use  in  land  transport  under  current  trends  and  adopted  policies  and  under  an  alternative  scenario 
achieving 60% GHG emissions reduction by 2050, EU28 

These  scenarios  illustrate  the  importance  of  alternative  fuels  in  achieving  future  decarbonisation 
scenarios. Given the likely continued demand for liquid and gaseous fuel in all transport modes in the 
long term (albeit to different extents), prioritising use in different modes over time  could be based on 
the  range  of  benefits  that  alternative  fuels  can  bring  to  a  particular  mode.  From  a  GHG  perspective 
displacing petroleum based fuels in any sector is likely to bring similar benefits, so additional benefits in 
terms of air quality improvements, infrastructure costs, fungibility with current assets (drop-in fuels) and 
In  terms  of  R&I,  an  additional 
affordability  become 
consideration in relation to prioritisation is to foster those areas of public and private sector R&I where 
the  EU  is  most  competitive  and  the  potential  impacts  across  different  objectives  are  greatest.  Also, 
consideration  should  be  given  to  the  potential  export  markets  of  innovative  technologies  in  other 
regions of the world affected by pollution and decarbonisation. 

important  distinguishing  considerations. 

1.4  GHG emissions savings from alternative fuels in the EU 28 
According to the IEA’s Energy Technologies Perspective the use of conventional fuels will need to rapidly 
decrease (as a result of efficiency gains and modal change) and the share of alternative fuels will need to 
rapidly  increase  in  order  to  achieve  a  2  degree  scenario.  In  the  absence  of  alternative  fuels  some 
transport modes (maritime and aviation) cannot decarbonise. 

The 2 degrees scenario implies savings of roughly 800Mt CO2 (Figure 8) compared to current emissions, 
of  which  the  use  of  biofuels  could  contribute  around  200Mt  CO2  by  2050  (Figure  9),  provided  that 
advanced  biofuels  production  does  not  lead  to  increased  emissions  from  direct  or  indirect  land-use 
changes and average CO2 emission savings over conventional fuels is 70%.Biofuels use would grow from 
a  current  value  of  roughly  615PJ  (14.7  Mtoe,  3.2%  of  total  energy  use  in  transport)  to  about  3,150PJ 
(75.3 Mtoe, 24.4% of total energy use in transport). 

8 

 
 
 
Total final energy consumption in the transport sector 

Hydrogen

Biofuels

Electricity

Natural Gas and LPG

Residual Fuel

Jet fuel

Conventional diesel

Conventional gasoline

J
P

18 000

16 000

14 000

12 000

10 000

8 000

6 000

4 000

2 000

 0

2012

2020

2025

2030

2035

2040

2045

2050

Figure 7 - Total energy consumption in the transport sector in the 2 degree scenario in EU28 (PJ) (Source: IEA ETP (2015)) 

)
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(

s
n
o
i
s
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i

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2
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A

1 600

1 400

1 200

1 000

 800

 600

 400

 200

 0

6 Degree Scenario

4 Degree Scenario

2 Degree Scenario

2012

2020

2025

2030

2035

2040

2045

2050

Figure 8 - Annual CO2 emissions from transport in different scenarios in EU28 (Source: IEA ETP (2015)) 

9 

 
 
 
 
 
 
 
 
 
 
 
 
)
2
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t
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(

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 250,000

 200,000

 150,000

 100,000

 50,000

 -

6 degree scenario savings

4 degree scenario savings

2 degree scenario savings

2015

2030

2040

2050

Figure 9 - Annual CO2 savings resulting from using biofuels instead of conventional fuels in EU28 (Source: IEA ETP (2015)) 

2  Objective, scope and approach of the STRIA on Alternative Fuels 

end-use 

The  aim  of  the  STRIA  on  Alternative  Fuels  is  to  identify  R&I  priorities  to  improve,  accelerate  and 
maximise the impact of the use of alternative fuels in transport, focus public and private funding in this 
area, and contribute to alignment of the EU & MS research agendas.  

It  will  take  into  consideration  the  future  prospects  for  alternative  fuels  use  in  the  context  of  other 
options and trends for meeting energy and environmental objectives in transport and the availability of 
alternative fuels. Specifically, it will consider the potential evolution of electromobility and its impact on 
other powertrain technologies and their fuels. 

A technical glossary is provided in Appendix 7.2. 

2.1  Scope 
The STRIA on Alternative Fuels wishes to be comprehensive in its coverage of transport modes, possible 
alternative fuels and the powertrains they can be used in. 

The  alternative  fuel  categories  considered  for  the  different  transport  modes  are  provided  in  Table  2, 
bearing in mind that hydrogen and electricity are the subject of a separate STRIA on electromobility. The 
STRIA  focuses  on  the  engine  technology  therefore  the  fuel  categorisation  is  based  on  chemical  and 
physical properties of the fuels.  The  fuels considered could be of renewable of fossil origin, but  while 
some alternative fuels of fossil origin could have benefits in relation to air quality and energy security, 
for example, compared to incumbent fossil fuels, achieving significant GHG emissions savings would rely 
on renewable alternatives. 

10 

 
 
 
 
 
 
 
 
 
 
Table 1 - Alternative fuel categories and transport modes considered by the STRIA 

Road 
LDV 

HDV 

Rail 

Waterborne  Aviation 

Fuel categories 
Methane-based (liquid) 
Methane-based (gas) 
LPG, bioLPG 
Alcohols, ethers & esters 
Synthetic paraffinic fuels 

Examples of fuels included in the different categories are provided in Table 2. 

Table 2 – Fuel categories considered and examples considered by the STRIA 

FUEL CATEGORIES 

Methane-based fuels 
LPG (Propane- and Butane-based fuels) 

Alcohols, Ethers & Esters 

Synthetic paraffinic and aromatic fuel 

Examples 
CNG, LNG, bio-methane, E-gas 
LPG, BioLPG 
Ethanol,  Butanol,  Methanol,  MTBE,  ETBE,  DME, 
BioDME, FAE 
GTL, HVO, BTL, SIP, ATJ, CH, SAK   

The powertrain technologies considered in scope for the STRIA are provided in Table 3. 

Table 3 – Powertrain technologies considered by the STRIA 

TECHNOLOGY 
Powertrain 
category 
Spark Ignition 

Spark Ignition 

Compression 
Ignition 

Powertrain 
technology  
Spark 
assisted combustion 

Ignition 

Acronym  

Specific examples  

/ 

SI 

CAI 

Spark  Ignition  -  lean 
combustion 

SI - lean 

homogeneous 

Both 
stratified lean 

lean 

and 

Compression Ignition 

CI   

Compression 
Ignition 

Compression Ignition - 
Dual Fuel 

CI - DF 

Fuel cell 

Fuel  Cells  other  than 
hydrogen fuelled ones  

FC 

HCCI,  PPC  (also  includes  PPCI,  GCI, 
LTGC  and  other  low  temperature 
combustion  systems  that  are  not 
spark assisted 
Such  as  NG  dual  fuel  (including 
HPDI)  or  methanol  dual  fuel  where 
the pilot fuel is a diesel type fuel for 
ignition purposes 
Direct Methanol Fuel Cell, LNG  FC 

Turbine 

Turbine 

Turbine 

Turbofan aircraft engines 

Table 4 below provides a definition of the transport modes considered. 

11 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Table 4 – Transport modes definition 

TRANSPORT MODES 
Definition 
Category 
Road vehicles <3.5T for people and goods transportation 
Light Duty Vehicles 
Heavy Duty Vehicles  Road vehicles =>3.5T for people and goods transportation 
Rail 
Waterborne 
Aviation 

Rail locomotives for people and goods transport13 
From inland waterways to ocean going14 
Jet aviation15 

2.2  Approach 
The following approach was taken to identify the strategic research and innovation priorities in relation 
to alternative fuel use in different transport modes: 

 
Identify options for using alternative fuels (i.e. alternative fuel and powertrain combinations) 
  Assess the  potential  impact  of different uses of alternative fuels based on criteria that  reflect 
policy  objectives  (GHG  savings   (TTW  via  engine  efficiency);  air  quality  pollutants  reduction; 
energy diversification; EU competitiveness) 
Identify challenges and opportunities for improved or novel use of alternative fuels 
Identify  research  needs  to  accelerate  development  of  alternative  fuel  use,  with  focus on  high 
impact  options  (i.e.  options  that  are  likely  to  have  greatest  impact  on  across  the  criteria 
considered) 
Identify requirements to address R&I needs 

 
 

 

 In developing the STRIA, the following aspects need to be considered: 

  Trade-offs between the different criteria of interest in relation to policy objectives 
 
Level of impact vs ease of implementation of alternative fuel options 
  The timeframe over which the R&I can have an impact on the market 

Extensive stakeholder consultation was conducted in preparing the STRIA on Alternative Fuels, through 
a  survey,  interviews  and  a  stakeholder  workshop  held  on  24  May  2016.  The  list  of  stakeholders 
consulted is provided in Annex 7.4. 

3  State of the art on alternative fuel end-use   

The  following  sections  describe  the  status,  trends  and  barriers  of  alternative  fuels  in  transportation. 
Table 5 below shows current and future applicability of fuel and  powertrain combinations to different 
transport modes, based on the following indicators: 

  Commercial in use, meaning that the technology is mature and that it is currently sold into the 

market commercially  

13 Only non-electrified locomotives are considered here  
14 Smaller boats for recreational use are not considered here 
15 Only  passenger  and  freight  turbofan  aircrafts  are  included.  General  aviation  and  particularly  vehicles  using 
AVGAS are not considered in this document due to their  small size as energy consumers. Also, many are using 
standard automotive fuels and would therefore decarbonize in parallel to these. 

12 

 
 
 
 
                                                           
  Under development, meaning that industry is actively developing products that are likely going 

to be launched into the market within 10 years 

  Research  stage,  meaning  fundamental  research  is  undertaken,  and  products  using  this 

technology are not expected to be market ready within 10 years   

Table 5 – Maturity of fuel and powertrain combinations 

Fuel Type 

Methane 
based 
liquid & gas  

Powertrai
n  
SI 

CI 

LDV 

HDV 

Waterborne 

Rail 

Aviation 

Commercial  

Commercial  

Under 
development 

Commercial 
as  dual  fuel 
and 
dedicated 
engine 
gas 
applications. 

to 
Euro 
New 

Current  dual 
fuel 
technology 
unable 
meet 
VI. 
compliant 
technology 
under 
development 
&  potentially 
in 
available 
2017 

Research 
stage 

Under 
development 

Research 
stage 

Under 
development 

Under 
development 

Commercial - 
DME  &  ED95 
in  dedicated 
fleets.  
FAME  widely 
adopted  as 
blend  with 
diesel 
Research 
stage 

Commercial 
as  dual  fuel 
application 
with 
methanol. 

use 

FAME 
under 
development
.  Other  fuels 
at 
research 
stage 

Research 
stage 

Research 
stage 

13 

Turbine 

LPG 

SI 

Alcohols, 
ethers, 
esters 

SPF 

SI 

CI 

FC 

SI 

in 

Commercial - 
retro-fit 
technology. 
CEN 
standard 
place 
Commercial - 
Ethanol  and 
M&ETBE  are 
widely 
blended  into 
gasoline.  
Commercial - 
FAME  widely 
adopted  as 
blend  with 
diesel. 

Research 
stage 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Fuel Type 

Powertrai
n  
CI 

Turbine/ 
Turbofan 

Other 

SI 

Composit
e  piston-
turbo 
cycle 

LDV 

HDV 

Waterborne 

Rail 

Aviation 

Commercial 
–  HVO  used 
vehicles. 
in 
Under 
development 
FT-diesel  
– 
properties 
being 
investigated 

Commercial 
–  HVO  used 
vehicles. 
in 
Under 
development 
FT-diesel 
– 
properties 
being 
investigated 
Research 
stage 

Research 
stage- 
Gasoline 
Naphtha 
Research 
stage 

/ 

Commercia
l  –  HEFA  in 
use.  Under 
developme
nt  -  various 
SPK fuels  

3.1  Light Duty Vehicles 
Light Duty Vehicle technology and the fuels it uses are driven by tail pipe emission limits as well as fleet 
average CO2 tail pipe targets.  Both these emissions are currently measured across the New European 
Drive  Cycle (NEDC),  following  a  particular  testing  procedure  to  determine  roadload  and other  factors. 
This testing procedure will be replaced in 2017 by the World Harmonised Test Procedure (WLTP) with a 
Real  Driving  Emissions  (RDE)  as  an  additional  test  procedure  to  ensure  real  world  compliance  within 
certain  conformity  factors  for  pollutant  emissions.  Fuel  standards  for  gasoline  and  diesel  are  in  place 
(EN228 and EN590 respectively). EN228 allows the blending of alcohols and ethers to set amounts, for 
example 10% of ethanol by volume. FAME (biodiesel) is allowed to be blended into fossil diesel up to 7% 
by volume (8% in France).  

The  fleet  average  CO2  targets  are  set  at  95g/km  for  2021  and  could  be  reduced  to  between  68  & 
78g/km by 202516. So far these targets have driven large scale uptake of diesel especially for the larger 
and heavier vehicles that do significant mileage such as larger passenger vehicles and vans due to the 
higher  efficiency  of  the  diesel  cycle.  This  and  fuel  taxation  favouring  diesel  has  created  a  diesel  / 
gasoline ratio that is significantly biased towards diesel (2.6 in 2015) [1, 38]. As a consequence the EU is 
an  importer  of  diesel  and  an  exporter  of  gasoline,  potentially  making  the  displacement  of  diesel  by 
alternative fuels more attractive for refiners and in balance of payments terms.  In the medium term it is 
expected that the CO2 targets will drive  a wide-scale  uptake of new  engine and vehicle technology in 

16

http://www.europarl.europa.eu/sides/getDoc.do?type=REPORT&mode=XML&reference=A7-2013-

151&language=EN 

14 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                                                           
the LDV sector including increased levels of electrification and hydrogen. These energy vectors are the 
subject  of  the  STRIA  on  electromobility,  however  electrification  through  hybridisation  will  have  an 
impact  on  engine  size  and  consequently  on  the  type  of  engine  and  its  fuel  compatibility.  A  systems 
approach  is  required  for  the  development  of  such  powertrains.  Increased  electric  propulsion  power 
does mean that engines can be further optimised to operate more efficiently and more cleanly within a 
smaller speed / load operating window as well as have lower transient requirements.  

EU emission standards apply  to all motor vehicles  and limits the permissible  tailpipe  emissions of CO, 
HC, NOx, PM and PN. Current  Euro6  standards  came into force in 2013.  Very effective aftertreatment 
devices  such  as  the  Three  Way  Catalysts  (TWC)  for  most  gasoline  vehicles  and  oxidation  catalysts 
combined  with  a  Lean  NOx  Trap  (LNT)  and /  or  Selective  Catalytic  Reduction  (SCR)  as  well  as  a Diesel 
Particulate Filter (DPF) for diesel vehicles are available and in operation today. These systems, especially 
the  diesel  aftertreatment  systems,  can  be  costly,  which  could  become  another  driver  to  push  the 
development  of  alternatively  fuelled  powertrains.  For  example  fuels  without  carbon  to  carbon  bonds 
inherently demonstrate very  low  levels of particulates, which would allow  the engine  to be optimised 
for  lower  GHG and  NOx  emissions  leading to  lower aftertreatment  system  costs,  which  in  turn would 
offset possible engine adaptation costs for alternative fuels. The introduction of limits beyond EURO 6c 
or  a  tightening  of  the  RDE  conformity  factors  (not  currently  foreseen)  would  require  additional 
aftertreatment  control  systems  making  gasoline  and  diesel  engine  technology  more  expensive  to 
produce and potentially more expensive to operate.   

On the fuel side, the Renewable Energy Directive (RED), with a renewable energy in transport target of 
10% by energy by 2020, has been the main driver for the growth in alternative renewable fuels in road 
transport. 

CEN standards exist for Gasoline (EN228), Diesel (EN590), LPG (EN589), paraffinic fuels (EN15940), B10 
(EN14214), and are under development for natural gas and E85. Gasoline and diesel are widely available 
throughout the EU. Various MSs have a separate pump for E10. Sweden has a significant E85 forecourt 
infrastructure. LPG is relatively widely available throughout the EU. A relatively dense natural gas (CNG) 
infrastructure  exists  in  MSs,  such  as  Austria,  Belgium,  Bulgaria,  Czech  Republic,  Germany,  Italy,  the 
Netherlands, Sweden and Switzerland ,other MSs such as the UK and Ireland have hardly any CNG filling 
stations17. The LNG infrastructure is developing partly through the LNG Blue corridor projects, but is far 
from  dense  enough.  While  private  infrastructure  is  already  sufficient  for  many  applications,  public 
infrastructure  for  electric  vehicles  is  expanding  rapidly,  but  is  not  dense  enough  in  some  areas  to 
provide an integrated network, in particular as far as fast charging is concerned. Fragmentation of the 
connectors and of the payment methods further contributes to this lack of coherency in the eyes of the 
end user. Hydrogen infrastructure is developing especially in Germany, the UK and Scandinavia, but still 
in its infancy. The latter two will be covered in STRIA on Electromobility. 

Research and innovation needs for the LDV sector, including a timeline, are captured by Ertrac [7] in the 
figure below and are broadly aligned with the findings in this report.  Current research activities focus 
strongly on pollutant emissions reduction to meet upcoming Real Driving Emissions as well as improving 
vehicle  efficiency  to  meet  fleet  tailpipe  CO2  targets.  Beyond  this  most  research  focuses  on  new  high 
efficiency,  low  polluting  combustions  systems  that  work  well  in  combination  with  increased  levels  of 
vehicle electrification. These include Homogeneous Charge Compression Ignition (HCCI), Cold Air Intake 

17 http://www.cngprices.com/station_map.php 

15 

 
 
                                                           
(CAI),  Partially  Premixed  Combustion  (PPC),  Low  Temperature  Combustion  (LTC)  and  others,  but 
essentially they share the aim of efficient combustion at lower temperatures to reduce engine out NOx 
emissions  and  are  therefore  captured  in  this  report  under  the  broad  category  of  Low  Temperature 
Combustion  (LTC)  systems.  Developing  a  suitable  novel  combustion  system  taking  into  account  the 
potential of alternative fuels should be a priority.    

Figure 10 - Research and innovation needs for the LDV sector. Source: Energy Carriers for Powertrains Ertrac [7] 

Table  6  provides  a  summary  on  the  state  of  the  art  of  alternative  fuel  use 

in  LDVs.

16 

 
 
 
Table 6 – State of the art on alternative fuel use in LDVs 

LDV 

How  much 
used and why? 

is 

How is it used? 

Natural Gas / Bio-methane / E-gas 
There  is  renewed  interest  in  natural  gas  for 
transportation  recently.  For  the  LDV  sector 
this  is  partly  driven  by  the  lower  carbon 
content  of  the  fuel  per  unit  of  energy 
resulting  in  lower  tailpipe  CO2  emissions 
helping  OEMs  to  meet  the  95gCO2/km 
is  also  an 
target. 
Improving  air  quality 
lower  noise 
important  driver.  For  HDVs 
levels  may  also  be  a  consideration.  Lower 
fuel  cost  as  a  result  of  lower  fuel  duty  per 
unit  of  energy  compared  to  gasoline  and 
diesel  has  helped  the  uptake  of  this 
technology. 
Natural  gas 
(including  dual-fuel),  bio-
methane  E-gas  use  in  light  duty  vehicles  is 
typically  in  adapted  spark  ignition  engines. 
The gas is combusted homogeneously and a 
Three  Way  Catalyst  (TWC)  is  used  to  meet 
tail  pipe  emissions  legislation.  The  gas  is 
in  a  200bar  on-board 
commonly  stored 
pressure  tank.  Vehicles  with  these  engines 
and  fuel  tanks  are  widely  commercially 
the 
in  Europe  directly 
available 
manufacturer.  The  technology  can  also  be 
retrospectively added to the vehicle. 

from 

Alcohols, ethers & esters 
The  use  of  ethanol  and  FAME  has  steadily 
been 
RED 
requirements  

increasing 

satisfy 

to 

paraffinic 

Synthetic 
fuel (FT, HVO, GTL) 
Not  used  Europe-wide 
on  a  large  scale  yet. 
HVO  used 
large 
quantities in Finland. 

in 

Liquid  petroleum  gas  and 
bioLPG 
LPG  consumption  in  LDVs  is 
driven  by  lower  fuel  costs 
comparing to Diesel. 

Synthetic 
(drop-in) 
fuels  can  in  principle 
be  used  as  substitutes 
(in any blend ratio) for 
diesel, gasoline and jet 
fuel.  

Ethanol  is  the  most  widely  used  alcohol 
blended  into  gasoline  up  to  10%  (v/v)  [4]. 
Small  amounts  of  methanol  and  higher 
alcohols  are  also  allowed  to  be  blended 
into  gasoline  within  EN228  limits.  E85  is 
used in FFVs in certain areas within the EU 
(such  as  Sweden,  France  and  Germany). 
MTBE  &  ETBE  are  commonly  used  ethers 
blended  into  gasoline.  FAME  is  currently 
blended  into  diesel  up  to  around  7%  (v/v) 
within EN590 limits. Higher blend ratios or 
pure  FAME  is  used  in  dedicated  fleets. 
EN228  and  EN590  fuels  do  not  require 
vehicle  modifications.  Fuels  outside  the 
specifications  need  relatively  minor  well 
understood changes in order to operate 

LPG is typically used in Spark 
Ignition  engines 
through 
simple 
relatively 
modification  of  the  original 
vehicle.  LPG  is  stored  as  a 
liquid  under  approx.  5bar 
the 
pressure,  gasified 
vehicle  and  injected  in  the 
ports  or  manifold.  This 
widely 
technology 
commercially  available  and 
widely  used  across  the  EU. 
fuel 
LPG  as  a  motor 
is 
EN589 
the 
covered  by 
standard.   

in 

is 

17 

 
 
 
Trends 

in 

the 

variation 

CEN/TC  408  standard  for  natural  gas  and 
biomethane for use in transport and CEN/TC 
326  standard  for  natural  gas  vehicles  - 
fuelling  and  operation  are  being  developed 
and will help increase the uptake of gas and 
infrastructure 
the  CNG 
promotion  of 
development,  as  the  existence  of  standards 
helps various parties across the supply chain. 
Depending  on 
gas 
specification allowed in the standard, engine 
efficiency improvements are to be expected 
due to the high octane of methane gas which 
is  strongly  synergetic  with  downsizing.  
It  was  reported  in  [2]  that  the  share  of 
natural  gas/  biomethane  mixtures 
is 
expected  to  increase  to  8.3  –  12.5  Mtoe  by 
2020  (5%  market  share  in  the  transport 
sector)  and  20.8  –  25Mtoe  by  2030  (10% 
market share). 
It is thought that this is due to a combination 
of  consumers  willing  to  buy  a  CNG  vehicle 
due  to  the  lower operating  costs  and  OEMs 
willing  to  produce  due  to  the  lower  CO2 
emissions. 

LPG is widely established and 
has slowly been growing.  

E10 and B7 limits constrain uptake.  
Sustainability  concerns  over  use  of  raw 
vegetable  oils  for  FAME  will  constrain 
supply. ILUC Directive cap of 7% by energy 
contribution from food-crop based biofuels 
may constrain growth [3, 39].  

The  technology  is  at 
an  early  commercial 
stage. 
Production 
capacity  is  already  at 
5.7 million tonnes GTL 
per year and close to 3 
million 
tonnes  HVO 
per year [4]. However, 
this production mainly 
takes  place  outside 
Europe. 

18 

 
 
Vehicle 
challenges 
opportunities 

& 

technical 

Other 
and 
infrastructural 
barriers 

duty). 

Engine 

CNG  is  a  suitable  option  for  LDVs.  The 
additional cost of especially the tank can be 
offset  with  the  lower  fuel  cost  (due  to  the 
lower 
efficiency 
fuel 
improvements  due 
to  high  octane  of 
methane  gas,  synergetic  with  downsizing. 
.Significant  variation  in  the  make-up  of  grid 
natural  gas  makes  engine  optimisation  a 
challenge. 
  Standardisation  of  the  fuel 
quality  for  CNG  and  bio-methane  under 
CEN/TC  408  would  help  with  engine 
optimisation  and  use  in  gasoline  and  diesel 
engines, and is expected to be voted upon in 
early  2017.  The  previous  publication  of  EN 
16726 Gas infrastructure - Quality of natural 
gas - Group H provided an initial step in gas 
standardisation .  
Lack  of  forecourt  infrastructure  in  certain 
MSs  remains  the  main  barrier  to  uptake  of 
CNG. Currently MSs such as Austria, Belgium, 
Bulgaria, Czech Republic, Germany, Italy, the 
Netherlands,  Sweden  and  Switzerland  have 
well developed CNG infrastructure. Methane 
slip throughout the WTT pathway presents a 
further 
challenge,  which  needs 
analysed 
new 
technologies.  
power 
Transportation 
generation  and  heating  for  sustainable  gas. 
The overall availability of sustainable gas and 
regulatory 
the  exact  nature  of 
the 
framework  will 
attractiveness  of  wide  scale  uptake  of 
sustainable gas in transportation. 

the 
likely  determine 

and  mitigated  with 

competes  with 

to  be 

New  engine  &  vehicle  technology 
is 
required  to  accommodate  higher  levels  of 
alcohols  and  ethers  in  SI  engines.  These 
changes  are  well  understood,  mature  and 
relatively cost effective. The higher octane 
of  alcohols  and  ethers  are  synergetic  with 
downsizing  and  should  lead  to  increased 
thermal  efficiency  for  optimised  engines, 
which  might  partially  compensate  the 
lower energy content. Higher FAME blends 
are  possible,  but  require  engine  and 
fuelling  system  changes  and  would  most 
likely 
aftertreatment 
considerations. 
Higher  ethanol  content  would  require 
some infrastructure change. 

require 

Within  EN228  there  is  significant  room  to 
blend  biofuels  (mixtures  of  alcohols  and 
ethers)  and 
replace  more 
therefore 
gasoline  in  the  LDV  sector.  Alcohols  in 
particular  could  however  also  be  used  as 
diesel replacement (such as ED95, see HDV 
sections),  which  in  the  longer  term  might 
be  more  desirable  if  the  gasoline  /  diesel 
ratio 
in  the  EU  becomes  even  more 
unbalanced.  The  FAME  content  in  diesel 
can in principle be increased with adapted 
vehicle and engine technology and used in 
LDV,  HDV  and  other  diesel  consuming 
machinery  

No  real  challenges  for 
these 
adoption  of 
fuels  in  transport  as 
direct 
they 
are 
to 
replacements  up 
the 
level  of 
any 
incumbent fuels. 

technical 
There  are  no 
further 
for 
barriers 
in 
increasing  use  of  LPG 
LDVs. 
efficiency 
Engine 
improvements  are  possible 
due  to  the  high  octane  of 
LPG, 
the 
assuming 
standardised 
composition, 
which  is  strongly  synergetic 
downsizing.  Direct 
with 
injection  of  liquid  LPG  could 
allow for further downsizing, 
potentially  enhancing 
the 
thermal  efficiency  of  the 
engine further. 

Challenges  are  mainly 
around the production 
process  scale  and  cost 
This 
effectiveness. 
largely  on 
depends 
production 
volumes 
and  prices  relative  to 
the alternative. 

LPG  forecourt  infrastructure 
is  established,  but  could  be 
enhanced  to  stimulate  more 
LPG vehicles. 
It is possible to use LPG as a 
dual  fuel  or  blended  with 
DME 
engines 
potentially in LDV and HDVs 

CI 

in 

19 

 
 
3.2  Heavy Duty Vehicles 
Heavy duty road vehicles (trucks and buses) are predominantly powered by diesel engines currently. 
This  is  a  consequence  of  the  superior  fuel  efficiency  and  low  end  torque  compared  to  SI  engines 
resulting in better operating characteristics.  

Diesel  engines  naturally  suffer  from  high  engine-out  emissions,  particularly  NOx  and  Particulate 
Matter,  which  so  far  have  been  very  successfully  countered  by  increasingly  sophisticated,  costly, 
bulky  aftertreatment  systems.  Cost  effective  alternative  fuels  that  have  cleaner  combustion 
characteristics could therefore play a significant role in powering the HDVs of the future. Currently 
the focus seems to be mainly on LNG, but many other options could contribute. These could include 
DME, ethanol or methanol with an ignition improver, HVO or some of the other synthetic paraffinik 
kerosenes (SPKs), while increased levels of FAME with improved aftertreatment systems could also 
play  a  role,  even  though  some  of  these  alternatives  entail  modifications  in  the  engines  and 
infrastructure and might therefore not be optimal from an overall system standpoint. 

Current research activities in the HDV sector focus strongly on improving fuel consumption for lower 
cost of operation of the complete vehicle. For the powertrain this focuses on reducing waste energy 
as  well  as  high  efficiency,  low  polluting  combustions  systems.  These  combustion  systems  are 
available in various formats and have a large number of names (HCCI, CAI, PPC, LTC and others), but 
essentially share  the  aim of  efficient  combustion  at  lower temperatures  to  reduce  engine  out  NOx 
emissions and are therefore captured here in Low Temperature Combustion systems (LTC). Research 
into a number of different alternative fuels is ongoing (including DME, ED95, NG) and for OEMs the 
focus is strongly focused on developing cost-effective  system solutions integrating varying levels of 
electrification with combustion engines depending on typical duty cycles the product will experience. 
This is also shown in figure 9 where “hybridisation” and “transient electric research” go hand in hand 
with  engine  “right  sizing”  and  “high  efficiency  research  narrow  operation”.  Research  is  also  taking 
place on the electrification of roads18. 

Figure 11 - Schematic ICE HD research needs in relation to HD vehicle energy consumption [7] 

18 https://www.scania.com/group/en/first-electric-road-nearly-ready-for-operation/ 

20 

 
 
 
                                                           
Table 7 provides a summary on the state of the art of alternative fuel use in HDVs. 

Table 7 – State of the art on alternative fuel use in HDVs 

HDVs 

How  much 
used and why? 

is 

Natural Gas / Bio-methane / E-gas 
There  is  renewed  interest  in  natural  gas 
for  heavy  duty  transportation  recently. 
For  the  HDV  sector  this  is  largely  driven 
by  the  much  lower  fuel  duty  per  unit  of 
energy  compared  to  diesel  and  the  Euro 
VI  emissions  requirements.  The  increase 
in  re-fuelling  stations  availability  has 
helped the uptake of this technology. 

Alcohols, ethers & esters 
The  use  of  FAME  has  steadily  been 
RED 
increasing 
requirements 

satisfy 

to 

Liquid petroleum gas and bioLPG 
Negligible use in HDVs 

Synthetic  paraffinic 
fuel (FT, HVO) 
Not  used  in  Europe 
on  a  large  scale  yet, 
except  HVO  in  some 
countries 
like 
Finland. 

21 

 
 
 
HDVs 

How is it used? 

diesel 

Natural Gas / Bio-methane / E-gas 
Natural gas and bio-methane use in heavy 
duty  vehicles  is  currently  mainly  in  spark 
ignition 
(SI)  engines.  These  engines 
typically  have  a  lower  efficiency  than 
engines,  while 
incumbent 
compliance  with  Euro  VI  standard 
is 
simpler  as  it  only  needs  a  Three  Way 
Catalyst.  Natural  gas  is  also  used  in  dual 
fuel CI engines, but these do not currently 
meet  the  EURO  VI  methane  emission 
limits. 
A second generation of dual fuel engines 
utilising  High  Pressure  Direct  Injection  is 
being  developed  by  a  number  of  OEMs 
targeting  EURO  VI  compliance  while 
retaining diesel like efficiencies   
The  gas  is  either  stored  in  200bar  on-
board  pressure 
in 
tanks 
cryogenic  liquid  form  (LNG).  LNG  has  a 
higher  energy  density  than  CNG  and  is 
therefore used for long distance haulage. 
The  technology  is  commercially  available 
in  Europe.  The  technology  can  also  be 
retrospectively added to the vehicle. 

(CNG)  or 

Liquid petroleum gas and bioLPG 
The  use 
currently 
in  HDVs 
insignificant,  but  could  possibly  be 
interesting for dual fuel applications.   

is 

Synthetic  paraffinic 
fuel (FT, HVO) 
Synthetic  fuels  can 
as 
used 
be 
substitutes  (in  most 
blend 
for 
diesel,  gasoline  and 
jet fuel assuming the 
finished  fuels  meet 
the 
appropriate 
standards. 

ratio) 

Alcohols, ethers & esters 
Biodiesel  and  particularly  FAME  are 
extensively  used  in  HDVs  through 
blending  (up  to  7%  by  volume)  with 
diesel.  Higher  blend  levels  up  to 
B100  are  used  in  dedicated  fleets. 
The  use  of  alcohols  with  an  ignition 
improver  is  commercially  available 
from  Scania.  Volvo  has  developed 
be 
engines  which 
DME 
commercialised  once 
fuel 
becomes  available.  The  uptake  of 
alcohol and DME engines is currently 
very limited. 

can 
the 

22 

 
 
 
HDVs 

Trends 

engine 

Natural Gas / Bio-methane / E-gas 
CEN/TC 408 standard for natural gas and 
bio-methane  for  use  in  transport  and 
CEN/TC  326  standard  for  natural  gas 
vehicles - fuelling and operation are being 
developed  and  will  help  increase  the 
uptake  of  gas  and  promoting  of  the  LNG 
infrastructure  development. 
  Various 
projects  (such  as  the  LNG  blue  corridor 
in 
and  GasOn)  are  currently  running 
Europe to increase the infrastructure and 
technology availability.  
Increasing 
efficiency  while 
engine 
maintaining 
characteristics and low emissions are the 
key 
lean 
combustion,  HCCI  and  PPCI  and  use  of 
heat recuperation to benefit of the higher 
temperature of SI exhausts. 
Much research also takes place in further 
and 
dual 
optimising 
aftertreatment technologies.   
It  was  reported  in  [2]  that  the  share  of 
natural  gas/bio-methane  mixtures 
is 
expected  to  increase  to  8.3  –  12.5  Mtoe 
by  2020 
in  the 
(5%  market  share 
transport  sector)  and  20.8  –  25Mtoe  by 
2030 (10% market share). 

focus.  These 

include  SI 

practical 

engine 

fuel 

Alcohols, ethers & esters 
DME  and  ED95  applications  have 
been developed by Volvo and Scania 
respectively  and  are  commercially 
available. So far the uptake has been 
limited  to  mainly  buses  in  Sweden 
due  to  infrastructure  requirements. 
VTT 
researching 
methanol  with  an  ignition  improver 
(MD95). 
Some  higher  biodiesel  applications 
exist  also  in  the  field  in  dedicated 
fleets.  

currently 

is 

Liquid petroleum gas and bioLPG 
LPG  is  predominantly  thought  of  as  a 
fuel for spark ignition engines. A High 
Injection  dual  fuel 
Pressure  Direct 
system 
been 
apparently 
has 
in  HDVs 
developed  for  application 
(workshop discussion)  

Synthetic  paraffinic 
fuel (FT, HVO) 
The  technology  is  at 
an  early  commercial 
stage. 
Production 
capacity is already at 
tonnes 
5.7  million 
GTL  per  year  and 
close  to  3  million 
tonnes  HVO 
per 
year.  However,  this 
production  mainly 
takes  place  outside 
Europe. 

23 

 
 
HDVs 

Vehicle 
challenges 
opportunities 

& 

Natural Gas / Bio-methane / E-gas 
LNG  is  a  suitable  option  for  long  haul 
HDVs,  where  CNG  is  better  suited  to 
shorter  distance  HDVs  and  LDVs.  Natural 
gas  is  also  used  in  dual  fuel  CI  engines, 
but these do not meet the EU VI methane 
emission limits. 
A second generation of dual fuel engines 
utilising  High  Pressure  Direct  Injection  is 
being  developed  by  a  number  of  OEMs 
targeting  EURO  VI  compliance  while 
retaining  diesel 
like  efficiencies.  The 
additional cost of especially the LNG tank 
can  be  offset  with  the  lower  fuel  cost 
(due 
duty).  
Standardisation of the fuel and increasing 
infrastructure  are  key 
the 
enablers to increase uptake.  
Methane slip from the whole fuel chain is 
a  significant  concern  and 
is  being 
addressed  with  research  and  technology 
improvements. 
Reducing  methane 
emissions from on-board fuel storage and 
evaporation require further investigation 

forecourt 

lower 

fuel 

the 

to 

require 

Alcohols, ethers & esters 
Higher  FAME  (TAME)  blends  have 
been  demonstrated  to  be  possible, 
but  require  engine  and 
fuelling 
system  changes  and  would  most 
aftertreatment 
likely 
considerations.  
The  wider  uptake  of  alcohol  based 
fuels either with a premixed ignition 
improver,  as  a  dual  fuel  application 
or in an optimised SI engine could be 
of interest. While ED95 technology is 
mature  and  a 
fuel 
other 
standard 
technology would need some further 
development 
fuels 
and 
standardising. 
DME  technology 
is  available  and 
relatively  mature.  ASTM  and  ISO 
standards  exist  which  could  be 
translated into a CEN standard. 

reference 
the 

exists, 

the 

Synthetic  paraffinic 
fuel (FT, HVO) 
No  real  challenges 
for adoption of these 
transport 
fuels 
in 
exist  as 
they  are 
direct  replacements 
of 
incumbent 
fuels.  Challenges  are 
mainly  around  the 
production  process 
scale 
cost 
and 
effectiveness 

the 

Liquid petroleum gas and bioLPG 
SI engine efficiency improvements are 
possible  due  to  the  high  octane  of 
standardised 
LPG,  assuming 
the 
composition,  which 
strongly 
is 
synergetic  with  downsizing.  Direct 
injection of  liquid LPG could  allow  for 
further 
potentially 
enhancing  the  thermal  efficiency  of 
the  engine  further.  Dual  fuel  could 
also 
efficiency 
improvements,  but  would  require 
significant  aftertreatment  equipment 
to meet Euro VI  

downsizing, 

further 

unlock 

24 

 
 
HDVs 

technical 

Other 
and 
infrastructural 
barriers 

network 

Natural Gas / Bio-methane / E-gas 
Lack  of  infrastructure  remains  the  main 
barrier  to  EU  wide  take  up  of  LNG.  CNG 
was covered in the LDV section. Currently 
only  certain  MSs  such  as  Spain,  the  UK 
and the Netherlands have developed LNG 
infrastructure.  The  LNG  blue  corridor 
project  is  aiming  to  add  a  significant 
number in strategic location to develop a 
Europe. 
practical 
Methane  slip 
the  WTW 
pathway and variation in the make-up of 
grid 
further 
challenges. Transportation competes with 
power  generation  and  heating 
for 
(sustainable)  gas.  The  overall  availability 
of sustainable gas and the exact nature of 
the  regulatory 
likely 
determine  the  attractiveness  of  wide 
scale  uptake  of  (sustainable)  gas 
in 
transportation. 

framework  will 

throughout 

present 

natural 

across 

gas 

in  the 

Alcohols, ethers & esters 
Within  EN228  there 
is  significant 
room to increase ethers. Alcohols in 
particular  could  be  used  as  diesel 
replacement  which 
longer 
term  might  have  more  impact.  The 
FAME  content 
in 
principle  be  increased  with  adapted 
vehicle  and  engine  technology  and 
used  in  LDV,  HDV  and  other  diesel 
consuming  machinery.  There 
is 
currently no DME infrastructure. 

in  diesel  can 

Synthetic  paraffinic 
fuel (FT, HVO) 
This  depends  largely 
production 
on 
volumes  and  prices 
relative 
the 
alternatives 

to 

Liquid petroleum gas and bioLPG 
There are no real technical barriers for 
further  increasing  LPG  in  HDVs.  The 
infrastructure  would  need 
to  be 
adapted / upgraded for HDVs however 

25 

 
 
3.3  Rail 
The railway network in the EU in 2010 was 212,800 km with 112,000 km of electrified rail lines [9]. All 
member states rail strategies favour further electrification, but there are routes where electrification 
is not economically viable. On these routes locomotives fuelled with alternative fuels can play a role. 

In  2010  GHG  emissions  from  the  railways  sector  were  7.4  MtCO2eq,  excluding  emissions  from 
electricity  consumption,  representing  0.6%  of  transport  share  (UIC/IEA  2014).  Rail  engines  are 
classed  and  regulated  as  Non  Road  Mobile  Machinery  (NRMM).  This  is  currently  at  stage  IV  with 
stage V emission regulation under consideration and can be found in the 2004/26/EC directive [11, 
23]. In the 2010 “Rail Sector Strategy 2030 and beyond” [24], the European rail sector set a vision to 
reduce specific energy consumption by 50% by 2050. Also, by 2030, the European railway sector has 
targeted  to  reduce  total  emissions  of  NOx  and  PM10  by  40%  and  aims  at  zero  emission  by  2050. 
Developing  flexible  engine  systems  able  of  maximum  fuel  conversion  efficiency,  and  integrating 
emissions  reduction  technologies  and  hybrid  propulsion  systems  will  contribute  to  achieve  these 
targets [24] in areas where electrification is not an option. 

To meet increasingly ambitious emissions reductions and efficiency gains, rail transport is considering 
the  use  of  alternative  fuels  such  as  liquefied  natural  gas  (LNG),  liquid  biofuels,  synthetic  fuels  and 
hydrogen,  and  also  looking  at  improvements  in  energy  efficiency  and  weight  reductions.  Biodiesel 
(FAME)  could  also  be  an  alternative  fuel  [9,  10].  However,  existing  diesel  traction  engines  running 
with  blends  in  excess  of  B30  can  lead  to  increased  fuel  consumption  and  decreased  power,  and 
higher maintenance costs. The use of liquefied natural gas (LNG) is also beginning to gain interest as 
an  alternative  rail  propulsion  system  [25,  26].  Considering  the  chemical  composition,  LNG  and  bio-
methane  (LBG)  offer  reductions  of  pollutant  particulate  matter  emissions  and  tailpipe  GHG 
emissions. The WTW GHG emissions of LNG depend largely on the levels of methane slip and source 
of the gas. However, this technology is considered for new locomotive development rather than for 
retrofitting  of  existing  ones,  due  to  the  extra-space  needed  for  LNG  tanks.  Hybrid  diesel-electric 
locomotives  that  capture  braking  energy  and  store  it  in  batteries  can  offer  significantly  reduced 
energy consumption and lower emissions. If the technology develops sufficiently to be cost-effective, 
larger scale energy storage on electric trains could provide them the ability to run on non-electrified 
routes [12]. Another technology considered by the rail industry in the drive towards zero emissions is 
fuel cells. 

Table 8 provides a summary on the state of the art of alternative fuel use in rail transport. 

26 

 
 
Table 8 – State of the art on alternative fuel use in rail 

RAILWAY 

How  much 
used and why? 

is 

Biodiesel 
No use reported in Europe. 
B20  (ASTM  D7467)  was  tested 
2010/2011 in the US 

in 

How is it used? 

AMTRAK (USA) and BNSF Railway (USA) 
used B20 for one-year tests 

Trends 

A  number  of  European  rail  operators 
have  carried  out  trials  on  rail  vehicle 
and engines (e.g. French SNCF, German 
DB, Czech CD, Hungarian MAV). 

Vehicle 
challenges 
opportunities 

& 

Other  technical 
and 
infrastructural 
barriers 

/ 

temperature  starting 

Challenges include:  
Lower energy content 
Poor 
low 
operation 
Poor  oxidation  stability  and  water 
absorption characteristics  
Opportunities include: 
Higher  cetane  number  and  flash  point 
as well as improved lubricity 
Biodegradable and low toxicity 
(these  are  similar  for  all  vehicles  and 
depend on the blend ratio) 
Incompatibility with certain elastomers 
and natural rubbers. 
More rapid lubricating oil degradation. 
Degradation during long-term storage. 

in  Europe 

LNG / Liquid bio-methane / Egas 
Diesel  prices 
remain 
considerably  higher  than  NG  on  an 
energy-equivalent basis [26].  
LNG  is  used  in  pilot  demonstrator  in 
Spain,  with  claims  that  NOx,  CO  and 
PM are  reduced by 70%,  and GHG by 
20-30%. 
Russian  Railways  have  tested  gas-
reciprocating  traction  technology  in 
2015, while in 2013 trials began of the 
world's first LNG-powered locomotive 
(TEM19). 
TEM19  with  gas  reciprocating  engine 
has  modular  design  and  is  equipped 
with  multifunctional  microprocessor 
control and monitoring system. LNG is 
stored in a removable cryogenic tank. 
Trials  have  also  taken  place  other 
countries e.g. Canada, and small scale 
liquefaction  technology,  such  as  GE’s 
MicroLNG,  could  allow  to 
liquefy 
natural  gas  at  any  point  along  a  gas 
distribution  network.  Lower  running 
costs  associated  with 
LNG  are 
appealing 
not 
Technology 
retrofitting the existing locomotives. 
Modular design significantly simplifies 
locomotive maintenance and repairs. 
It  takes  less  time  to  warm  up  the 
engine in the cold weather/regions. 

available 

for 

Switching  from  diesel  fuel  to  LNG 
would 
require  a  new  delivery 
infrastructure for locomotive fuel 

3.4  Waterborne transport 
Waterborne transport from recreational craft to large ocean-going cargo ships is driven primarily by 
diesel  engines  (around  99  %).  Approximately  77%  of  waterborne  fuel  consumption  is  low‐quality, 

27 

 
 
 
 
 
low-price residual fuel referred to as heavy fuel oil (HFO), which tends to be high in sulphur (2.7%) 
[13].  The  Waterborne  transport  sector  has  internationally  recognised  standards  that  define  the 
characteristics of fuel oils and what they can contain so that they will be suitable for use on-board 
ships,  ISO  8217:2012  being  the  most  widely  used  standard.  The  next  edition  is  expected  in  2016 
which could include biodiesel blends as a new series of distillate waterborne fuel grades [20]. 

Alternative fuels are considered in waterborne applications due to emission legislation. These include 
SOx  regulations  for  operating  in  the  Sulphur  Emissions  Control  Areas19 (SECA)  and  force  ship 
operators  to  either  install  expensive  exhaust  after  treatment  equipment  or  switch  to  low‐sulphur 
fuels. Directive 2012/33/EU sets limits at 1.5% sulphur in waterborne fuel oil for all ships in the North 
Sea  and the  Baltic  Sea; 1.5%  sulphur  in  fuel  for  all passenger  ships  in the  other  EU  seas,  and  0.1% 
sulphur  fuel  at  berth  in  ports.  European  inland  navigation  is  classed  and  regulated  as  Non  Road 
Mobile  Machinery  (NRMM).  This  is  currently  at  stage  IV  with  stage  V  emission  regulation  under 
consideration and can be found in the 2004/26/EC directive [11, 23].  

Outside of European waters, Canada and the US coastline have the first introduced emission control 
zone for SOx, NOx and PPM's in 2016. NOx is regulated by the MARPOL NOx standards for all ships 
built since 2000 [21, 30].  

In  2010  GHG  emissions  from  the  total  European  navigation  sector  were  171.4  MtCO2eq  (19.3 
inland  navigation  and  152.1  MtCO2eq  from  maritime  transport)  excluding 
MtCO2eq  from 
international bunkers (international traffic departing from the EU), representing 14.1% of transport 
emissions  [21].  By  2050,  the  target  for  maritime  transport  is  to  reduce  GHG  emission  by  40% 
compared to 2005 [22]. But, the current trend points to an increase in future shipping GHG emissions 
as  a  result  of  projected  growth  in  global trade.  Significant  measure  in  relation to energy  efficiency 
and fuel substitution are required [27].  

Alternative low(er) carbon fuels such as biofuels, methanol and methane based gases (CNG, LNG) can 
help  satisfy  the  above  requirements  by  substituting  the  fossil  fuels  currently  in  use.  But,  where 
dedicated  engines  are  used  fuels  will  need  to  be  available  in  sufficient  quantities  worldwide  or 
regionally  for  bunkering.  Currently,  the  focus  is  mainly  on  LNG,  but  methanol  is  also  receiving 
significant interest, with Stena Line deciding to retrofit one of its vessels to use methanol [9, 16, 29, 
30].  The  Alternative  Fuel  Infrastructure  directive  (Directive 2014/94/EU)  requires  national  action 
plans for LNG bunkering facilities. 

Current  research  activities  in  waterborne  transport  are  concentrated  on  combustion  systems  to 
reduce  emissions  and  fuel  consumption. This  includes  research on  dual-fuel  engines  and  advanced 
fuel injection systems to reduce emissions while maintaining or improving energy efficiency. Partially 
pre-mixed (and other forms of low temperature) combustion systems combined with exhaust gas re-
circulation  and  waste  heat  recovery  are  also  topics  of  research  for  the  same  reasons.  Methane 
leakage  throughout  the  fuel  supply  and  storage  chain  could  (partly)  offset  GHG  emissions  and 
requires further research. 

Table 9 provides a summary on the state of the art of alternative fuel use in waterborne transport.

19 MARPOL  annex VI. Established SECA in Baltic,  North Sea  and English Channel where a phased reduction of 
SOx emissions was initiated. The allowable amount of fuel sulphur was reduced to from 1.5% to 1.0% in July 
2010 and is to be further lowered to 0.1% in January 2015. 

28 

 
 
                                                           
Table 9 – State of the art on alternative fuel use in waterborne transport 

Water-
borne 
How  much  is 
used 
and 
why? 

LNG / Liquid bio-methane / E-gas, CNG 
Depending  on  the  combustion  and  after  treatment 
technology  used,  LNG  can  lead  to  significant  emissions 
reductions. Reductions of 85–90% for NOx, near 100% for 
SOx and PM and 15-20% for GHG emissions were reported 
[14]. 
Methane  slip  (the  release  of  unburnt  methane)  is  a 
challenge but technologies are available to overcome some 
of this.  
The first LNG-fuelled ferry based on DNV GL standards was 
launched in 2000 [17]. 
In  EU  50 LNG-fuelled  ships  (excluding  LNG  carriers)  are  in 
operation  –  thereof  44  operate  in  Norway  and  2  in  other 
MSs. In addition, 45 LNG-fuelled ships are on order [19]. 
In 2016, very large cruise ships are on order with LNG dual 
fuel capability.  
CNG has a lower power density but is easier to handle and 
is feasible for recreational and inland craft. 

Alcohols & esters 
Interest  in  methanol  as  ship  fuel  is  growing  in 
response  to the  need  to  reduce  SOx  emissions.  In 
2015  STENA  Line  launched  the  first  methanol 
powered  ferry  [9,  29].  The  NOx  emissions  from 
methanol  are  45  %  of  those  of  conventional  fuels 
and SOx emissions are 8 % of those of conventional 
fuels  (per  unit  energy).  Further  reductions  are 
possible with aftertreatment 
Ethanol  is  blended  with  gasoline  in  small  boat 
engines [9].  
Butanol  has  similar  energy  density  and  octane 
number  as  gasoline,  which  allows  higher  blends 
without affecting the energetic performances.  
Biodiesel blend (B20) was tested with good results 
in US. 

fuel 

Synthetic  paraffinic 
HVO) 
Not  yet  used 
waterborne transport [30]. 

in  European 

(FT, 

29 

 
 
 
Water-
borne 
is 
How 
used? 

it 

LNG / Liquid bio-methane / E-gas, CNG 
LNG  as  a  shipping  fuel  is  a  proven  and  available  solution, 
with gas engines covering a broad range of power outputs.  
LNG  is  burned  either  in  stoichiometric  or  lean  burn  SI 
engines, in dual fuel direct injection (diesel cycle) engines. 
In  the  future,  LNG  maybe  used  in  high  temperature  fuel 
cells to achieve greater engine efficiencies.  

Trends 

For  maritime  transport,  the  implementation  of  Directive 
2012/33/EU  of 21  November  2012  as  regards the  sulphur 
content of Waterborne fuels is expected to be a driver for 
the promotion of LNG for ships [2]. 
80  LNG-powered  ships  are  under  construction,  with 
planned deliveries by 2018 (DNV GL, 2015) 
Market  studies  predict  that  the  LNG  demand 
for 
Waterborne  sector  will  reach  5.2  Mtoe  in  2020  and  8-12 
Mtoe in 2030 [15]. 
infrastructure  directive 20 requires 
The  alternative  fuels 
national  plans  to  foresee  the  deployment  of  LNG  fuel 
infrastructure in ports.  

20 http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=celex%3A32014L0094 

Alcohols & esters 
Methanol can be used in waterborne transport for 
inland as well as for short-sea shipping, where it is 
currently being tested. 
Methanol  is  combusted  according  to  the  diesel 
process, using a small amount of pilot fuel (MGO or 
HFO) for ignition. 
In  July  2013  DNV  released  rules  for  using  low 
flashpoint liquid (LFL) fuels, such as methanol. 
Biobutanol  (iB16)  fuel  blend  was  tested  in  US  in 
standard  Waterborne  engines  with  no  alterations 
to the engine or fuel system. 
Biodiesel  can  be  used  in  blends  (up  to 20  %)  with 
Waterborne  diesel  oil  or  Waterborne  gas  oil 
without  affecting  engine  performance.  The  new 
standard is expected in 2016. 
The  environmental  assessment  of  methanol 
produced from biomass has the potential to reduce 
life-cycle emissions by over 80% for GHG, SOx, NOx 
and PM, which is similar to LBG [40]. 
There  are  already  demands  on  methanol  as 
alternative  fuel.  Methanex  has  ordered  4  tanker 
ships  on  methanol.  Waterfront  Shipping  has 
commissioned 7 new chemical 
tankers  with  dual  fuel  methanol  engines  to  be 
delivered in 2016 [29] 
The  technology  for  biobutanol  is  not  yet  mature 
but US DoE anticipates the potential availability at 
industrial level. 

Synthetic  paraffinic 
HVO) 

fuel 

(FT, 

Dutch 

Energy 

in  the 

Vision 
The 
estimates penetration for GTL as 
a  fuel 
inland  shipping 
sector  to  11%  by  2030  and  19% 
in  recreational 
by  2050,  and 
vessels  to  19%  in  2030  and  31% 
in 2050 [2]. 

30 

 
 
 
 
 
                                                           
Synthetic  paraffinic 
HVO) 

fuel 

(FT, 

Water-
borne 
Vehicle 
challenges  & 
opportunities 

LNG / Liquid bio-methane / E-gas, CNG 
LNG propulsion technology is ready for application and has 
successfully  been  deployed  on  inland  vessels  since  2011 
[2].  
Further research and demonstration need to address 
above all methane slip due to its climate effect.  
Standardisation  of  the  filling  station  for  waterborne 
transport LNG and greater bunkering capacity would allow 
further  development  of  new  LNG-fuelled  ships  and  also 
support  increased deployment via the  retrofitting of ships 
to  LNG  [18]  and  promotes  gas  (LNG  &  L-CNG)  delivery  in 
regions where gas is currently unavailable. 
LNG offers significant  environmental benefits in particular 
when it is blended with liquid bio-methane [20]. 
Maximising  storage  efficiency  and  minimising  boil  off  is  a 
challenge. 
In  comparison  to  road,  marine  combustion  engines  are 
already  highly  efficient.  Potentially  greater  efficiencies 
maybe  achievable  through  electric  propulsion  and  high 
temperature LNG fuel cells.  

Alcohols & esters 
For using biodiesel in existing ships, the fuel system 
may have to be modified with biodiesel-compatible 
components.  Biodiesel,  especially 
in  higher 
concentration,  can  dissolve  certain  non-metallic 
materials  (seals,  rubber,  hoses,  gaskets)  and  can 
interact with certain metallic materials (i.g. copper 
and brass). For new ships and engines this is much 
less of a concern [30]. 
Methanol  has  a  heating  value  close  to  LNG  (LNG 
with  20.3  MJ/litre  and  methanol  has  19.8),  which 
entails  a  similar  performance  [2].  Also,  it  has  a 
relatively  low  flashpoint,  is  toxic  (skin  contact, 
inhaled  or  ingested)  and  its  vapour  is  denser than 
air.  As  a  result,  changing 
fuels  poses  new 
challenges  to  operators  in  terms  of  handling  and 
safety.  
The  conversion  of  an  existing  engine  to  burn 
methanol would bear less costs than an  
LNG retrofit work [2, 29]. 

31 

 
 
 
Water-
borne 
Other 
technical  and 
infrastructura
l barriers 

LNG / Liquid bio-methane / E-gas, CNG 
LNG  demands  more  space  for  fuel  tanks,  leading  to  a 
decrease in payload capacity [17]. 
Relatively high capital cost for the system installation [17]. 
The current low NG price compared to the conventional oil 
fuel  is  a  main  economic  driver  for  this  new  application. 
However, the current lack of LNG bunkering infrastructure 
presents  an  uncertain  picture  for  the  LNG  fuel  price.  This 
leads  to  uncertainty  for  ship  operators  on  whether  they 
could  benefit  from  the  offset  between  fuel  cost  savings 
and large capital investments. 
There 
infrastructure  and  an 
unharmonised  regulatory  approach  for  standardisation  in 
MSs,  which  will  be  handled  by  the  new  standardisation 
foreseen by CEN/TC 326 standard for natural gas vehicles - 
fuelling  and  operation  [15].  Due  to  the  lower  energy 
density on the intercontinental Europe Asia Route, fuelling 
within the Middle East may be required.   
The  availability  of  adequately  trained  port,  fuelling  and 
crew in the safe use of LNG must be ensured. 
Safety  of  LNG  during  fuelling  and  collision  must  be 
ensured. 

limited  refuelling 

is  a 

Synthetic  paraffinic 
HVO) 

fuel 

(FT, 

systems, 

Alcohols & esters 
The  new  mandatory  notation  LFL  FUELLED  covers 
aspects such as materials, arrangement, fire safety, 
electrical 
control  and  monitoring, 
machinery  components  and  some  ship  segment 
specific considerations. 
The availability of adequately trained port, fuelling 
and  crew  in  the  safe  use  of  methanol  must  be 
ensured. 

32 

 
 
 
3.5  Aviation 
Efforts  made  through  technological  progress  and  operational  improvements  have  improved 
significantly  the  energy  efficiency  of  air  transportation.  However,  even  with  the  most  radical 
technological progresses, the efficiency gains will not offset the expected traffic growth nor to allow 
to achieve the challenging commitments for decarbonisation made by the aviation industry by 2020 
and 2050 [31]. Synthetic fuels (drop in fuels) produced from renewable sources are expected to play 
a key role to cover this gap by 2050 [31].  

Commercial  aviation  commonly  uses  Jet-A1  (also  known  as  kerosene).  Due  to  the  high  cost  of 
aircrafts and the long fleet replacement time, and also to limit infrastructure changes, the aviation 
sector  is  likely  to  rely  on  liquid  fuels  similar  to  kerosene  to  2050  and  possibly  beyond,  and  is 
currently looking to drop-in sustainable fuels to the conventional, crude based, jet fuel i.e. fuels that 
when blended allow existing jet fuel specifications to be met. The composition of these new fuels is 
currently  mostly  paraffinic,  being  known  as  Synthetic  Paraffinic  Kerosene  (SPK)  or  iso-paraffins. 
There  are  5 major fuel routes approved for its use  in civil aviation: FT-SPK,  HEFA-SPK, HFS-SIP, FT-
SPKA/A and ATJ-SPK. There are other seven routes currently under approval process, plus other 15 
waiting to enter the process [32]. Sustainability of those pathways depends upon the feedstock and 
way of production. Feedstocks considered by the aviation industry21 are waste oils like used cooking 
oil (UCO), residual animal/vegetable oils from  industries, vegetable oils like camelina oil , tobacco, 
jatropha,  sugars  from  sugarcane,  lignocellulosic  material,  lignin  residues,  municipal  solid  wastes 
(MSW)  or  algae.  Wastes  and  residues  that  don’t  require  land  to  be  produced  usually  have  less 
sustainability concerns.  Drop-in fuels could also be produced from electric power (power-to-liquid 
(PTL) or sunlight (STL)).  

The alternative fuels mentioned are used blended with conventional Jet-A1 according to the limits 
established by the standard ASTM 7566. Once blended, the fuel is considered as Jet-A1 (ASTM 1655 
or DEFSTAN 91-91) and can be used in all civil infrastructures and aircraft that use jet fuel, which is a 
key  advantage  to  avoid  duplication  of  infrastructures  or  operations  [33].  The  blend  is  needed 
because  the  synthetic  hydrocarbons  fuels  do  not  contain  some  hydrocarbons  naturally  present  in 
fossil fuels such as aromatics, or other elements such as Sulphur, that are known to play a relevant 
role for the performance of the aircrafts fuel systems. Overall, these properties make the sustainable 
fuels  cleaner  at  combustion  (clearly  for  PMs  and  potentially  NOx)  and  with  higher  energy content 
(per weight unit) that translates to some limited energy efficiency gains (due to the reduced weight 
to be transported and a slightly more efficient combustion). However, the role of those compounds 
and their interaction with other parameters in the jet fuel are not fully understood, and knowledge 
is based on experience with fossil fuel rather than with these new synthetic alternatives.  This means 
that understanding the optimal properties and limits of blends requires further work.  

Most  production  and  use  of  alternative  fuels  in  commercial  aviation  has  been  for  demonstration 
and/or R&I purposes. Recently, the R&I profile of the use has changed with the blended use of HEFA-
SPK at Oslo airport [34] and the start of continuous production of HEFA-SPK by Altair in Los Angeles 
(CA) for use by United Airlines [35]. The incentive programs available in the USA and in particular in 

21 The feedstocks types cannot be considered sustainable per se. Sustainability should be demonstrated along 
the production chain. Those mentioned above have been used in aviation because in particular production 
chains  they  have  been  found  as  sustainable  according  to  internationally  recognized  standards  like  RSB 
(www.rsb.org) or ISCC (www.iscc-system.org) and the Directive 2009/28/EC. 

33 

 
 
                                                           
California  for advanced biofuels  are enabling  Altair production and are also driving the building of 
another  facility  for  FT-SPK  based  on  municipal  solid  wastes  [32].  At  European  level,  the  only 
incentive  for  airlines  using  biojet  fuel  is  the  EU  ETS  for  intra-European  flights  but  it  is  negligible 
compared with the price gap. However, at global level, there is a commitment for development and 
implementation a global carbon market mechanism (GMBM) from 2020 that could be an incentive 
for the use of sustainable, low carbon fuels but that, with the current layouts, would be also unlikely 
covering the price gap for biojet. 

The available production capacity of alternative fuels for aviation and its use is still limited globally, 
and is growing faster in USA than in Europe. This is due mainly to the lack of market due to the high 
costs  of  the  technology  and  insufficient  policy  incentives  e.g.  compared  to  road  transport.  This  is 
very much related to the difference between aspirational and mandatory targets. Also, the limited 
development of sustainable feedstock supply chains is a constraining factor.  

Recent developments in technology are leading to better affordability and higher availability, as well 
as higher GHG emissions reductions. But, due to the investment and time needed for the approval of 
new technologies for use in aviation, time to market of these new technologies could be significant 
without external support. For example, the approval of the latest technology from alcohols (Alcohol-
to-Jet - ATJ) has taken more than 5 years to be approved with costs in the range of several million 
euros 22.  

Table 10 provides a summary on the state of the art of alternative fuel use in aviation. 

22 ASTM Task Force item in ASTM D02-J6 was initiated by Gevo® in June 2010, final approval obtained in April 
2016. Extensive fuel property and engine/aircraft testing is required for the process, making it costly. At the 
end, the time for completing the process is uncertain for  the fuel producer,  as the total costs, due to that 
more/less fuel and tests would be needed depending on the findings. It is expected from ASTM to optimize 
the  process  to  reduce  the  hurdle,  but  there  are  still  limitations  regarding  the  number  of  testing  facilities 
available as there are many (around 20) pathways looking for the approval and more could join.  

34 

 
 
                                                           
Table 10 – State of the art on alternative fuel use in aviation 

Jet 
Engines 
How  much 
is 
used and why? 

How is it used? 

SPK (FT, HEFA, FT/A) 
Not  used  in  Europe  on  a  large  scale,  there  is  a  growing  interest 
about develop this fuels as they are considered large contributors 
for decarbonisation of air transport in the short and medium term 
[31].  More  than  1600  commercial  flights  have  been  done  using 
sustainable fuel blends from 20-50% [36].  
Use at airport as non-segregated fuel has started in January 2016 
in  Oslo  [34]  increasing  the  number  of  flights,  but  the  volumes 
needed to keep continuous supply are a challenge.  
There is no continuous production of drop-in fuels for aviation in 
Europe. 
Use outside Europe, mostly in USA, has been promoted by military 
contracts and now starting from private companies. 
Synthetic  paraffinic  kerosene,  once  it  has  been  blended,  can  be 
used as drop-in jet fuel.  
Maximum  blend  ratios  accepted  for  commercial  aviation  are:  FT-
SPK (50%), HEFA-SPK (50%) and FT-SPK/A (50%) [33]. 
Once the fuel has been blended and approved according the ASTM 
in  all  civil  aircrafts  and 
D7566  standard, 
infrastructures  using 
fuel  without  any 
segregation. 

it  can  be  used 
conventional 

jet 

ATJ 
Recently 
approved,  no 
use 
reported 
in Europe.  

at 

SIP 
Used 
Lab’line 
demonstration 
and 
project 
some  Airbus 
delivery 
flights, but not 
used 
a 
on 
continuous 
basis. 

It  can  be  used 
blended  with 
jet  fuel 
fossil 
up  to  10%  v/v 
[33].  

Can  be  used 
blended  with 
fossil  jet  fuel 
up  to  30%  v/v 
[33]. 

from 

HEFA+ 
HEFA+  refers  to  an 
the 
upgrading 
conventional 
green 
diesel  (HVO)  to  the 
quality 
aviation 
standards 
(cold 
temperature 
properties, density…).  
Not  yet  approved  for 
commercial  aviation, 
but testing is ongoing.  

HEFA  is  approved  up 
to  50%.  HEFA  +  could 
used 
probably 
be 
blended  with  fossil  jet 
fuel  up  to  10%  v/v 
[33]. 

LNG 
Not used.  

It  is  not  drop-
in, 
requires 
radical  change 
of 
airframe 
and 
combination 
with  electricity 
still  not  in  the 
market. 

35 

 
 
 
 
Jet 
Engines 
Trends 

Challenges  & 
opportunities 

SPK (FT, HEFA, FT/A) 
The technology is at an early commercial stage and the production 
capacity is still limited, which is mainly due to economic reasons. 
However,  HEFA  is  an  industrially  mature  technology.    Recently  a 
production facility in Los Angeles (CA, USA) has started continuous 
production of HEFA, able  to produce about 30,000 t of HEFA-SPK 
per  year  [35].  Besides,  outside  Europe,  there  are  several  offtake 
agreements  from  airlines  or  governments,  but  considering 
facilities still not running.  
In  Europe,  potential  production  capacity  according  to  the  EU 
Flightpath  and  the  latest  updates  could  reach  15,000  t  of 
sustainable fuel (FT-SPK) per year in France from 2018 [37]. 

There are almost no challenges due to their drop-in characteristics 
at  the  defined  blend  ratios,  but  to  reach  pure  use  is  still  not 
possible (but could potentially be).  
Minimum content in aromatics related to fuel system seals is one 
of  the  limitations  to  unblended  use  while  it  has  been  identified 
that  there  the  nvPM  emissions  lower  when  aromatics  are  also 
lower.  
Different aerosols, nvPM and shoot combustion profiles from SPK 
suggest different nonCO2 effects at high altitude that would need 
better understood to know the real decarbonisation potential. Use 
of  low  blend  ratios  of  green  diesel  (as  HEFA+  for  aviation)  SPK 
could  suddenly  increase  the  production  capacity  and  would 
increase  the  uptake  but  there  is  still  some  fuel  system  testing 
required. 

SIP 
The 
technology 
is 
at  an  early 
commercial 
stage  with low 
availability. 

ATJ 
The 
technology 
is 
at  an  early 
commercial 
stage  with low 
availability. 

Same  as  SPK, 
but blend ratio 
unlikely  to  be 
enlarged.  

a 

is 

This 
unique 
molecule 
vs 
the  incumbent 
what  is  more 
It 
complex. 
has 
reported 
that  the  10% 
ratio 
blend 
could 
be 
difficult  to  be 
higher.  

availability. 

HEFA+ 
is  a 
The  technology 
commercial stage with 
It 
high 
could 
easily 
be 
adopted  with  some 
‘minor’ 
adaptations. 
HEFA  (Green Diesel)  is 
well  developed 
for 
ground transport fuels 
but  the  extension  of 
HEFA+ 
is  still  to  be 
approved. 
low  blend 
Use  of 
ratios  of  green  diesel 
(as HEFA+ for aviation) 
SPK  if  approved  could 
suddenly  increase  the 
capacity 
production 
and 
the 
in  the  short 
uptake 
term,  but  there  is  still 
system 
fuel 
some 
testing 
to 
required 
know the limits. 
It  wouldn’t  be  a  long 
term  solution  due  to 
the low blend ratios. 

increase 

LNG 
Possibilities  of 
using  LNG  as 
jet 
fuel  are 
being explored 

Non  drop-in  is 
not  feasible  in 
the time frame 
real 
a 
for 
implementatio
n  but  it  could 
be  a  solution 
for the future. 

36 

 
 
 
Jet 
Engines 
Other  technical 
and 
infrastructural 
barriers 

SIP 

SPK (FT, HEFA, FT/A) 
Challenges are mainly around the production process scale and cost effectiveness. This depends largely on production volumes 
and prices relative to the alternative.  
For new fuels and modification of current blending limits, costly ASTM processes are a barrier. A better understanding of fuel 
composition limits (fit for purpose) could help to reduce the barrier significantly.  
There is no other alternative for aviation for decarbonisation or/and fuel independence in the short/medium term.  
There  are  some  technical  constraints  for  the  use  of  shared  civil-military  infrastructures  as  NATO  pipelines  that  need  to  be 
tackled to increase the use. 
The global character of aviation is a challenge regarding competitiveness.  
As opportunity, developing the compatibility standards of new technologies, the economic constraint could be overcome. 

HEFA+ 

ATJ 

LNG 
Long  time  to 
market, 
infrastructure 

37 

 
 
 
 
3.6  Summary of trends in alternative fuel R&I 
Underlying themes of vehicle powertrain research are increased efficiency and lowering of noxious 
emissions.  Alternative  fuels  could  help  with  these  aims,  but  the  extent  depends  on  their 
characteristics  and  levels  at  which  biofuels  are  blended.  As  a  result  engine  improvement  efforts 
tailored  to  alternative  fuels  will  depend  on  the  levels  of  gains  that  could  be  achieved  and  how 
biofuels will be used.   A brief overview of the main R&I activities is provided below by fuel type. 

3.6.1  Methane-based fuels 
Significant  efforts  are  currently  underway  to  develop  High  Pressure  Direct  Injection  equipment, 
which is effectively an improved dual-fuel injection system, and optimised dedicated gas combustion 
systems.  Lean  operating  dedicated  gas  engines  are  being  developed  for  waterborne  applications. 
There  is  also  evidence  that  dual  fuel  technology  is  being  developed  further  to  increase  diesel 
substitution  rates  and  minimise  methane  slip  for  heavy  duty  road  and  waterborne  transport.  The 
focus on light duty vehicles is on further downsizing by making use of the high octane of these fuels. 
On-board  storage  of  especially  LNG  also  attracts  significant  R&D  attention  across  the  transport 
modes in order to make it cheaper, easier to install and lower leakage.  Bio-methane and power-to-
gas technologies could enable a transition to lower carbon content fuels. 

A significant number of projects have been conducted focussed on CNG and LNG for both heavy and 
light duty road transportation. Figure 12 gives an overview EU funded activities and their focus. 

EU collaborative research supporting Natural Gas development 

Figure 12 - EU funding actions and industrial outcomes on Natural Gas technologies  for road transport  (source: Ertrac 
Future light and heavy duty ICE powertrain Technologies) [7] 

There  is  also  significant  activity  within  industry  at  the  moment  which  is  not  covered  in  the  above 
figure, including EURO VI compliant dual fuel combustion systems for HDVs, including methane slip. 
Methane slip remains an issue throughout the fuel supply chain to the engine, while aftertreatment 
systems can reduce tailpipe emission to very low levels. R&I efforts are required to reduce the WTT 
methane emissions, and possibly evaporative emission from on-board fuelling systems. 

38 

 
 
 
LNG use in shipping is growing using largely based on dual fuel engines that allow operation on both 
fuel oil and natural gas.     

3.6.2  LPG 
Some  of  the  activities  discussed  in  the  methane-based  fuel  section  also  apply  to  LPG,  specifically 
around  HPDI.  For  LPG  this  currently  appears  to  mainly  involve  the  LDV  sector  even  though  the 
technology is equally applicable to HDV and some waterborne applications. 

3.6.3  Alcohols, esters and ethers 
There is a significant  amount  of work  looking at  taking advantage of the  higher octane of alcohols 
and  ethers  in  Spark  Ignition  engines.  The  same  applies  to  higher  ester  blends  in  diesel  for  use  in 
Compression  ignition  engines  for  the  Light  Duty  and  Heavy  duty  transport  modes.  A  number  of 
academic institutions are researching high efficiency dedicated alcohol engines. DME and ED95 are 
commercially  available  products  awaiting  the  roll  out  of  infrastructure.  Further  work  in  this  area 
concentrates  on  improved  efficiency,  reduced  noxious  emissions  and  lowering  cost.  Work  is  also 
underway to research methanol with an ignition improver (MD95), and there is a significant level of 
activity on dual fuel systems using methanol in the waterborne sector in order to improve efficiency 
and lower noxious emissions. The rail sector could benefit from the efforts led by other sectors. A 
number  of  companies  and  institutions  are  developing  methanol  and  ethanol  fuelled  fuel  cell 
technology for mainly LDVs, HDVs and waterborne applications either as main propulsion or auxiliary 
power supply. The focus of this research is around cold start operation, high efficiency, reliability and 
cost. 

An  example  of  EU  funded  projects  for  land  transport  is  the  BEAUTY  project  which  focussed  on 
ethanol as a diesel substitute mainly  for LDVs  but failed to achieve  significant improvements  even 
when optimising the engines for the fuel's characteristics. For waterborne application methanol as a 
dual  fuel  application  has  been  widely  research  in  a  number  of  projects  as  shown  in  Figure  13.  In 
addition, the HERCULES-2 project is focussed on increased fuel flexibility of waterborne applications. 

Figure 13 - Timeline showing some of the main projects investigating the use of methanol as a marine fuel [8] 

3.6.4  Synthetic Paraffinic Fuels 
SPKs are largely drop-in and would therefore require less engine development. Significant efforts are 
taking  place  in  using  HVO  blended  with  diesel  in  mainly  LDV  and  HDV  applications.  During  the 

39 

 
 
 
stakeholder  engagement  workshop  the  consensus  was  that  not  enough  is  known  about  the  exact 
properties of more novel SPK fuels and that therefore further research is required to investigate how 
powertrain technology could be further optimised.  

40 

 
 
4  Potential benefits of alternative fuel use in different transport 

modes and engines 

Table 5 shows the multitude of options that are in use and being considered for different transport 
modes. From a technical point of view, there are two key distinguishing factors that are relevant to 
policy objectives: Well-to-Wheel GHG emissions and Tank-to-Wheel noxious emissions.  

For the WTW GHG emissions it is important to understand that the majority of the benefit is likely to 
come from utilising renewable (low carbon) alternative fuels (WTT). A smaller but not  insignificant 
contribution can be made by increased vehicle and therefore powertrain efficiency (TTW), which is 
the focus of this report. TTW noxious (pollutant emissions) contribute to the urban air quality issues 
experienced in cities across the world. It is however worthwhile noting that correctly regulated and 
implemented  aftertreatment  control  systems  such  as  found  on  EURO  VI  trucks,  can  address  this 
issue. Certain alternative fuels and combustion systems have inherently lower engine-out emissions 
that might enable cost-effective aftertreatment systems for potential future pollution limits. This is 
discussed in more detail in section 4.1.     

There are then two other factors that are potentially important in prioritising different options:  EU 
competitive position and energy diversification.  

EU competitive  position relates  to the extent that any  fuel and technology  option  could  provide a 
competitive  advantage  to  the  EU  industry.  Energy  diversification  relates  to  the  potential  of  the 
option to contribute to the diversification of energy supply to different modes. 

4.1  Alternative fuels effect on GHG and noxious emissions 
Alternative fuels can have a positive impact on both TTW GHG and pollutant emissions due to their 
chemical composition and properties.  

There are two main mechanisms by which the fuel can reduce tailpipe GHG emissions. Firstly, fuels 
with  a  higher  H/C  ratio  per  unit  of  energy  will  automatically  have  lower  exhaust  CO2  emissions. 
Secondly, increasing the engine efficiency through utilising specific properties of the alternative fuel 
can  bring  about  further  CO2  reductions.  Engines  are  typically  developed  with  a  particular  fuel  in 
mind.  The  narrower  the  specification  of  the  fuel  the  more  engine  hardware  and  software  can  be 
optimised  with  respect  to  engine  efficiency  (GHG  emissions)  and  pollutant  emissions.  For  road 
vehicles  this  effect  has  been  demonstrated  over  the  years  with  gasoline  and  especially  diesel, 
however in contrast , increased fuel processing to obtain a narrow fuel specification can in itself be 
more costly and GHG intensive. A balance between a narrow specification fuel with a fully optimised 
engine and a wider specification fuel with a less optimised engine would need to be found.  

The  improvement  potential  of  TTW  GHG  emissions  is  important  but  relatively  small  (<10%) 
compared  to  the  WTT  improvements  that  switching  to  a  low  carbon,  renewable  fuel  would  have 
(>60%).  

For pollutant emissions it is important to understand the difference between engine out and tailpipe 
emissions. Engine out emissions are not only a function of fuel, but also of the combustion process 
and  combustion  system  design.  Exhaust  gas  aftertreatment  systems  are  widely  used  (and  can  be 

41 

 
 
very  effective  as  demonstrated  by  heavy  duty  EURO  VI  compliant  vehicles)  to  control  tailpipe 
emissions to “within” the required limits set for the application. Lowering engine-out emissions will 
therefore  not  automatically  result  in  lower  tailpipe  emissions,  unless  these  are  likely  to  be  lower 
than  any  legal  limits  aimed  at  by  aftertreatment  systems.  Lower  engine-out  emissions  could 
however  enable  OEMs  to  meet  lower  emissions  limits  at  a  lower  cost.  Specifically,  fuels  without 
carbon to carbon bonds inherently demonstrate very low levels of particulates. This effect could be 
utilised  to  reach  a  better  compromise  between  NOx  and  CO2  emissions  in  compression  ignition 
engines. Within the marine sector where currently little or no aftertreament is used, switching from 
residual  fuel  oils  to  alternative  fuels  such  as  LNG  or  methanol  offers  the  possibility  of  significant 
reductions in SOx (>90%), particulates and NOx emissions (>80%).  

Table 11 below summarises promising fuel and powertrain technology combinations with regard to 
TTW GHG emissions and TTW noxious emissions, with a focus on alternative fuel induced technology 
improvements in different transport modes. The options below are derived from a literature review 
and  consultation  with  stakeholders  resulting  in  an  assessment  of  fuel  and  powertrain  technology 
combinations as captured in Appendix 7.3.  

42 

 
 
Table 11 - Summary table of most promising fuel and technology propulsion options by transport mode 

TTW GHG emissions 
Alcohols and ethers in SI engine: 
Use  of  alternative  fuels  with  higher  RON, 
such  as  alcohols,  ethers  and  methane, 
could increase SI engine efficiency by up to 
5%.  This  could  allow  further  downsizing  / 
either 
downspeeding. 
stratified  or  homogeneous  has 
the 
increase  the 
potential  to  significantly 
engines  thermal  efficiency  and  hence 
lower CO2 emissions. 

Enleanment 

Alternative fuels in Fuel Cells:  
Enabling  FC  introduction  based  on  fuels 
such as alcohols could lead to GHG savings 
of  10-20%  compared  to  spark 
ignition 
engines, depending on operating regime.  

Gaseous  (methane  &  LPG)  fuels  in  SI 
engines:  
High  Pressure  Direct  Injection  systems  are 
under  development  by  e.g.  Westport  / 
Prins  that  aim  to  reduce  CO2  by  10% 
relative to the current gas SI systems. 
OEMs  are  engaged  in  Low  Pressure  Direct 
Injection  development,  as  well  as  other 
activities (e.g. GasOn project), with the aim 
to  reduce  CO2  by  20%  relative  to  the 
current best in class SI CNG vehicles. 

SPFs: 
SPFs  from  a  range  of  sources,  including 
Power  to  Liquid  (PTL),  are  considered 
potentially  promising,  but  currently  the 
impact  of  their  specific  properties  on 
engine efficiency are not well researched. 

V
D
L

Significant 
market 
deployment 
expected by* 
2030 

TTW noxious emissions 
Alcohols and ethers in SI engine: 
Replacing  gasoline  and  diesel  with 
shorter HC chains potentially reduces 
engine out PM and NOx which could 
enable  better  engine  optimisation. 
Aldehyde  emissions  would  need  to 
be monitored 

Alternative fuels in Fuel Cells:  
Enabling  FC  introduction  based  on 
fuels  such  as  alcohols  could  lead  to 
emissions 
significant 
pollutant 
in  all 
reductions  of  nearly  100% 
emissions  compared  to  SI  engines. 
Aldehydes might be an issue 

2050 

2030 

Gaseous (methane & LPG) fuels in SI 
engines:  
Replacing  gasoline  and  diesel  with 
shorter HC chains potentially reduces 
engine out PM and NOx which could 
enable better engine optimisation 

SPFs: 
from  a  range  of  sources, 
SPFs 
including  Power  to  Liquid  (PTL),  are 
potentially  promising,  but  currently 
the 
specific 
of 
properties  on  noxious  emissions  are 
not well researched.  

impact 

their 

43 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Alcohols and ethers in CI engine: 
DME  &  ED95  engines  are  commercially 
available  and  meet  Euro  VI.  Engine 
efficiency is similar to diesel currently with 
further scope for improvement. 
High  Pressure  Direct  Injection  (HPDI)  dual 
fuel  systems  currently  being  developed 
would  also  be  suitable  for  alcohols  & 
ethers.  These  engines  have  negligible 
engine-out PM emissions. 

Gaseous  (methane  &  LPG)  fuels  in  CI 
engines: 
HPDI  systems  are  under  development  at 
e.g.  Westport  as  a  dual  fuel  application 
aiming  at  >90%  diesel  substitution  (by 
energy) and meeting current  diesel engine 
characteristics  incl.  efficiency.  Technology 
developers  also  claim  such  engines  would 
minimise methane leakage. 

SPFs: 
SPFs  from  a  range  of  sources,  including 
Power  to  Liquid  (PTL),  are  considered 
potentially  promising,  but  currently  their 
level  of  sustainability,  cost  and  impact  of 
its  specific  properties  on  engine  efficiency 
are not well researched. 
Alcohols and ethers in CI engine: 
DME  &  ED95  engines  are  commercially 
available  and  meet  Euro  VI.  Engine 
efficiency is similar to diesel currently with 
further scope for improvement. 
High  Pressure  Direct  Injection  (HPDI)  dual 
fuel  systems  currently  being  developed 
would  also  be  suitable  for  alcohols  & 
ethers. 

Gaseous  (methane  &  LPG)  fuels  in  CI 
engines: 
HPDI  systems  are  under  development  at 
e.g.  Westport  as  a  dual  fuel  application 
aiming  at  >90%  diesel  substitution  (by 
energy) and meeting current  diesel engine 
characteristics  incl.  efficiency.  Technology 
developers  also  claim  such  engines  would 
minimise methane leakage. 

SPFs: 
SPFs  from  a  range  of  sources,  including 
Power 
(PTL),  are  being 
considered,  but  currently  the  impacts  of 
their 
specific  properties  on  engine 
efficiency are not well researched. 

Liquid 

to 

V
D
H

l
i

a
R

2030 

2030 

2030 

2030 

engines 

Alcohols and ethers in CI engine: 
DME  & 
are 
ED95 
commercially  available  and  meet 
Euro  VI.  No  c-c  bonds  mean  that 
is 
engine-out  particulate  matter 
significantly reduced allowing further 
improvement 
in  NOx.  Aldehyde 
emissions  are  understood  to  be 
minimal.  

Gaseous (methane & LPG) fuels in CI 
engines:  
It  is  anticipated  that  these  systems 
will meet EURO VI limits.  

their 

SPFs: 
SPFs 
from  a  range  of  sources, 
including  Power  to  Liquid  (PTL),  are 
potentially promising, but the impact 
specific  properties  on 
of 
noxious  emissions  are  not  well 
researched. 
Alcohols and ethers in CI engine: 
are 
ED95 
DME  & 
commercially  available  and  meet 
Euro  VI.  No  c-c  bonds  mean  that 
engine-out  particulate  matter 
is 
significantly reduced allowing further 
improvement 
in  NOx.  Aldehyde 
emissions  are  understood  to  be 
minimal.  

engines 

Gaseous (methane & LPG) fuels in CI 
engines:  
It  is  anticipated  that  these  systems 
will meet EURO VI limits.  

2030 

SPFs: 
from  a  range  of  sources, 
SPFs 
including  Power  to  Liquid  (PTL),  are 
potentially  very  promising,  but  the 
impact of their specific properties on 
noxious  emissions  are  not  well 
researched. 

44 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Alcohols and gaseous fuels in (dual fuel) CI 
engine: 
Methanol  and  natural  gas  are  currently 
used in dual fuel engines. Engine efficiency 
is  similar  than  when  operated  on  fuel  oil 
with  further  scope  for  improvement  of  up 
to 5%. 
Engine  operating  fully  on  gas  or  methanol 
development 
are 
promising 
in 
efficiency  of  around  to  5%  under  certain 
conditions 

improvements 

currently 

further 

under 

to 

SPFs: 
SPFs  from  a  range  of  sources,  including 
Power 
(PTL),  are  being 
considered,  but  currently  the  impacts  of 
their 
specific  properties  on  engine 
efficiency are not well researched.  

Liquid 

2030 

Alcohols  and  gaseous  fuels  in  (dual 
fuel) CI engine: 
Methanol  and  natural  gas  dual  fuel 
engines have significantly lower NOx, 
particulate  matter 
and 
SOx 
emissions. 
Engine  operating  fully  on  gas  or 
under 
methanol 
further 
development 
reductions in pollutant emissions 

promising 

currently 

are 

SPFs: 
SPFs 
from  a  range  of  sources, 
including  Power  to  Liquid  (PTL),  are 
potentially promising, but the impact 
of  its  specific  properties  on  noxious 
emissions are not well researched. 

Synthetic hydrocarbon fuels as SPK, SIP or 
ATJ 
Current  synthetic  jet  blended  fuels  are 
promising fuels that would allow very small 
improvements  of  around  2% 
efficiency 
were  mentioned  by  experts  during  the 
workshops.  

Synthetic  hydrocarbon  fuels as  SPK, 
SIP or ATJ 
Synthetic  sustainable  jet  fuels  are 
promising  fuels  that  would  allow 
NOx,  SOx  and  nvPM  improvements, 
especially  linked  with  the  aromatic 
compounds and sulphur content. 

2030 

e
n
r
o
b
r
e
t
a
W

n
o
i
t
a

i
v
A

* please note: Time of implementation is sometimes governed by infrastructure availability 

4.2  EU competitive position 
Europe’s  competitive  position  relative  to  the  rest  of  the  world  is  in  this  context  defined  as  the 
technology leadership of its industry. For alternative fuels this could either mean specific technology 
required to  produce,  refine  and handle the  fuels, or technology that focuses on on-board storage, 
handling, combustion, aftertreatment and control of these fuels. 

Fuel production and infrastructure: 

Europe  has  a  strong  position  in  the  development of LNG  refuelling  infrastructure  for  fleets  (HDVs, 
rail and maritime) with several large companies developing and building new infrastructure e.g. the 
LNG Blue Corridor project. It also has a strong position in bio-methane production technologies via 
biological and thermochemical routes. There is also significant research and industrial activity for the 
production  of  alcohols  and  SPFs  from  biomass.  There  are  several  demonstration  and  early 
commercial  projects  for  the  production  of  ethanol  and  butanol  from  lignocellulosic  biomass, 
methanol from glycerine and from synthesis of H2 and CO2, and SPFs. These activities complement 
the strengths in the traditional refining sector.   

On-board technology: 

Alternative  fuels  can  present  significant  challenges  for  vehicle  manufacturers.  Overcoming  these 
challenges through technological advances would generate new IP which would in turn strengthen 
Europe’s leading position.  

45 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Specifically these would include: 

  On-board  CNG/LNG  storage  and  handling  for  LDVs,  HDVs,  waterborne  inland  and  marine 

transport and rail  

  Gas  or  alcohol  combustion,  fuel  handling  and  injection  systems  for  LDVs,  HDVs  and 

waterborne transport 

  Novel  and  advanced  aftertreatment  systems  taking  into  consideration  alternative  fuel  use 

and the disposal of the resulting residual wastes 

Alternative  fuels  could  also  bring  about  opportunities  especially  for  fuels  with  much  tighter  fuel 
specifications  than  gasoline,  diesel,  marine  oil  and  jet  fuel.  Making  full  use  of  these  properties  by 
increasing engine efficiencies while reducing noxious emissions and reducing cost could potentially 
present  a  significant  number  of  technological  advances  that  Europe’s  industry  is  well  placed  to 
capitalise upon. 

Maintaining  the  traditionally  strong  position  the  Europe  has  in  transport  related  manufacturing 
needs to be maintained, as emphasised by the recent EC Communication on “A European Strategy 
for  Low-Emission  Mobility”.  Research  and  innovation  in  engine  technologies  compatible  with 
alternative fuels could be an important element in maintaining this competitiveness.  

Figure  xx  illustrates  the  importance  of  the  European  automotive  industry  globally  and  in  terms  of 
employment, trade balance, innovation spending and tax income in Europe.  

46 

 
 
 
Figure 14: ACEA key figures on the automotive industry23 

4.3  Low carbon energy diversification 
Increasing  power  requirements  in  different  transport  modes  leads  to  lesser  options  in  terms  of 
alternative  fuels  because  of  difficulties  associated  with  electrification,  high  energy  density 
requirements and, in applications like aviation, stringent fuel specifications. The  lower the number 
of available fuel options to certain transport modes, the lower the number of options to decarbonise 
and to meet  other objectives  such as air quality and energy security. While this may lead to think 
that low carbon alternative fuels suitable for use in modes where options are limited should be used 
in those modes (e.g. biofuels should be used in aviation where there is no alternative to liquid fuel 
use  in  the  foreseeable  future),  this  validity  of  this  argument  will  actually  depend  on  the  relative 
benefits of using alternative fuels in different modes (e.g. are the benefits of using biofuels in road 

23 http://www.acea.be/uploads/press_releases_files/POCKET_GUIDE_2015-2016.pdf 

47 

 
 
 
 
                                                           
transport much greater than for aviation if electrification of road transport cannot be fully achieved 
or progresses slowly).  

On the other hand, it is also argued that using certain alternative fuels in certain modes may lead to 
lock in and slower uptake of preferred options (e.g. use of biofuels in passenger cars or HDVs). Lock 
in  could  also  result  from  the  significant  investment  that  would  need  to  be  made  in  infrastructure 
provision  (e.g.  CNG,  LNG,  as  well  as  hydrogen  and  electric).  Fuel  lock-in  can  be  prevented  by 
maintaining  optionality  through  stimulating  research  into  areas  that  provide  an  alternative  to  the 
current  leading  alternative  fuel  and  engine  technology  combination.  Policy  should  also  stimulate 
options  that  provide  solutions  for  the  longer  term.  This  is  particularly  important  for  some  of  the 
heavy  duty  applications  where  there  are  currently  not  many  alternatives  foreseen,  such  as  HDVs, 
waterborne and potentially aviation. For example the  use of alcohols, ethers and SPFs  in HDV and 
waterborne applications could well provide additional options relative to methane based fuels.   

The  added  advantage  of  optionality  is  that  it  automatically  provides  a  level  of  competition  and 
energy diversification. Invariably developing technology for more than a single fuel will be costly for 
the technology developers and hence some R&I funds could be utilised to cover this.     

4.3.1  Renewable fuel availability 
The production of alternative fuels is outside the mandate of STRIA, however their availability is an 
important  factor  when  assessing  future  option  and  therefore  strategy.  Biofuels  in  this  context  are 
considered to be advanced biofuels24. 

4.3.1.1  Biofuels (BTL, HVO, FAME, bioEthanol, bioMethanol, bioDME, bioLPG) 
The consumption of biofuels in the EU has oscillated in the past few years, mainly due to legislative 
uncertainty and amounted to 14 Mtoe in 2015. However, when referring to the future availability of 
biomass  feedstock  to  meet  the  demand  for  food/feed,  industrial  products  and  energy  (including 
biofuels)  the  recurring  theme  is  "uncertainty".    On  the  one  hand  biomass  supply  potential  is 
conditional  on  the  definition  of  sustainability  criteria  and  dependent  on  many  factors  (e.g 
productivity increases, technology development,  new  resources  such as  marine), and on the other 
hand,  estimating  future  biomass  demand  is  in  any  case  highly  complex  as  it  depends  on  a  great 
number  of  variables.  The  European  Commission  highlighted25 the  need  for  further  research  and 
analysis on whether there is sufficient supply of sustainable and cost-effective biomass feedstock for 
all  energy  uses  post  2020.  On  the  global  scale,  studies  also  highlight  the  great  variability  of 
estimations of future biomass potential26. The JRC is currently carrying out a comprehensive analysis 
on biomass supply and demand, identifying competition/synergies and possible trade-offs between 
various users. 

24 In  line  with  EC  communications  « A  policy  framework  for  climate  and  energy  in  the  period  from  2020  to 

2030” and “A European Strategy for Low-Emission Mobility” 

25 EC SWD(2014) 259 final: “State of play on the sustainability of solid and gaseous biomass used for electricity, 

heating and cooling in the EU” 

26 Saygin  et  al  (2014).  Renewable  and  Sustainable  Energy  Reviews  40,  1153–1167;  Smith  P.et  al.  2014: 
Agriculture, Forestry and Other Land Use (AFOLU). In: Climate Change 2014: Mitigation of Climate Change. 
Contribution of Working Group III to the Fifth Assessment Report of the IPCC 

48 

 
 
                                                           
The  Biomass  Futures  Atlas27 estimates  the  current  bioenergy  resource  in  Europe  at  a  level  of 
314Mtoe, which under a sustainability scenario could increase to 375Mtoe by 2020 and fall slightly 
to  353  Mtoe  by  2030.  A  follow  up  study,  EC  funded  research  project  Biomass  Policies,  which 
considered additional constraints on biomass availability, indicates that the sustainable potential for 
energy  uses  could  be  of  the  order  of  130Mtoe.  Another  study28,  also  estimates  that  agricultural, 
forestry  and  municipal  residues  and  wastes  could  represent  a  major  sustainable  resource  (around 
220 million tonnes, equivalent to around 95 Mtoe) and provide 16% of the transport energy needs 
by  2030,  taking  into  consideration  sustainability  constraints.  The  potential,  however,  might  lower 
due  to  constraints  on  the  accessibility  of  the  resource  and  competition  for  biomass  from  other 
sectors.  .   Currently 75% of  the biomass  used for energy  purposes  is allocated to heat  production, 
13% for electricity and 12% for biofuels29. Despite the potential for significant additional production, 
according to most forecasts, there will not be sufficient sustainable biomass for biofuel production 
to  cover  future  transport  energy  needs.  Even  more  so  considering  that  part  of  the  additional 
advanced biofuel production capacity might be used to replace food- based biofuels. 30 Nonetheless 
the potential for fuel production is significant. 

4.3.1.2  Bio-methane 
In 2013, 0.1 billion m3 of bio-methane were consumed in transport in the EU, which represents 3% 
of  the  CNG/LNG  used  in  transport  (3  billion  m3/year  or  2.5  million  toe).  In  2013,  there  were  282 
upgrading plants in 13 European countries (including Switzerland).  

The  level  of  total  bio-methane  production  foreseen  for  2020  in  the  National  Renewable  Energy 
Action Plans is about 12 billion m3 31 (about 10Mtoe). The Green Gas Grids project32 estimates that 
by  2030  methane-based  fuels  could  contribute  about  25-30  billion  m3 33 (up  to  about  25Mtoe)  to 
transport  energy  demand,  with  a  10%  contribution  from  bio-methane.  Bio-methane  feedstock 
availability is subject to the same considerations as for biofuels. 

4.3.1.3  Electricity 
In  the  past  years  the  share  of  renewable  electricity generation  has  continued to  increase,  nuclear 
production has remained stable and generation from fossil fuels has fallen significantly. In 2013 half 
of Europe’s total electricity came from low-carbon sources and the European electricity industry has 
made  strong  commitments  to  achieve  carbon  neutrality  by 2050.  However,  looking  at  the  current 
trends  the  European  Commission  has  assessed  that  the  52%  share  in  2012  of  carbon  free  gross 
electricity (from renewables and nuclear) could reach 58% by 2020, 66% by 2030 and 73% by 2050. 

27 Biomass Futures (2012) Atlas of EU biomass potentials. Deliverable 3.3: Spatially detailed and quantified 
overview of EU biomass potential taking into account the main criteria determining biomass availability from 
different sources. 
http://www.biomassfutures.eu/public_docs/final_deliverables/WP3/D3.3%20%20Atlas%20of%20technical%2
0 and%20economic%20biomass%20potential.pdf   
28 Malins et al. (2014) “Wasted. Europe’s untapped resource. An assessment of advanced biofuels from waste 
and residues   
29 According to AEBIOM statistical report 2015: http://www.aebiom.org/wp-
content/uploads/2015/10/AEBIOM-Statistical-Report-2015_Key-Findings1.pdf 
30 EC Communication « A European Strategy for Low-Emission Mobility” 
31 Source: EBA 
32 Partners participating in the Intelligent Energy Europe Green Gas Grids Project: www.greengasgrids.eu 
33 Source: EBA 

49 

 
 
                                                           
4.3.1.4  Hydrogen 
Hydrogen can be produced from renewable or nuclear energy by splitting water via electrolysis or by 
bio-methane reforming using organic matter as feedstocks, very low carbon pathways from well to 
wheel.  A  driver  for  hydrogen  production  could  be  the  need  to  store  electricity  from  intermittent 
renewable energy sources. 

5  Research agenda  

In this section we present the research and innovation needs and activities associated with fuel and 
powertrain  combinations  in  different  transport  modes.  The  focus  is  on  gaseous,  alcohols  and  SPF 
fuels  which  would  deliver  benefits  to  Europe  (see  section  4).  Non-technical  challenges  to 
deployment are also discussed where relevant. 

5.1  R&I needs 
5.1.1  LDVs 
Alcohol and ether blending into gasoline is a relatively cost-effective solution and is also relevant in 
vehicles that are partially electrified such as hybrids and range extender vehicles.  A more efficient 
use  of  alcohols,  ethers  and  gases  in  spark  ignition  (SI)  engines  could  be  achieved  by  optimising 
injection, combustion, aftertreatment systems and their control. By substantially increasing today’s 
blending ratios allowed in LDV petrol engines and optimising the engines for such blending, it would 
be possible to take full advantage of the higher octane content of alcohols and ethers. It is estimated 
that by increasing the blends from a 10% v/v maximum as specified in the EN228 standard to E85 it 
would be possible to achieve thermal efficiency improvements of around 5% or more, resulting in an 
equivalent decrease in CO2 emissions. Achieving this result would require the development of a fully 
dedicated  and  optimised  high  alcohol  blend  engine  and  combustion  system.  Further  research  is 
required  to  understand  the  extent,  impact  and  especially  control  of  currently  non-regulated 
emissions such as aldehydes. A research programme led by Ford on the use of ethers (DME & OME) 
has recently started, but it is too early to understand the potential of these fuels for LDVs. 

Similar  synergies  can  be  exploited  in  gas  engines  by  using  compressed  natural  gas  (CNG),  bio-
methane  or  methane  from  PTL.  Direct  injection  in  gas  SI  engines  has  the  potential  to  further 
improve  the  TTW  GHG  emissions  of  such  engines.  The  use  of  Low  and  High  Pressure  Direct 
Injection34 (LPDI  and  HPDI)  of  CNG  in  both  SI  &  CI  gas  engines  can  achieve  higher  efficiencies 
compared to relative incumbent CNG systems and lead to CO2 reductions by up to about 10%.   
Further  improvements  are  possible  in  SI  gas  engines  using  lean  combustion  or  Controlled  Auto 
Ignition  combustion  systems.  These  advanced  combustion  systems  could  make  full  use  of  the 
properties  of  (bio-)methane  and  leverage  even  larger  efficiency  improvements.  These  combustion 
systems  also  lend  themselves  very  well  for  integration  in  hybrid  applications.  More  cost  effective 
and easier to package on-board storage systems are required for all gaseous fuels.  

Synthetic  Paraffinic  Fuels  are  effectively  a  drop-in  fuel,  which  makes  them  very  attractive  and 
potentially easy to adopt even into an existing fleet, but more work is required to understand how 
fuel properties can improve engine efficiency and reduce pollutant emissions.  

34 High Pressure Direct Injection. A technology developed specifically for natural gas, which injects both the alternative fuels and the small 
amount of diesel as pilot fuel directly into the cylinder. The technology maximises the use of alternative fuel while maintaining equal 
horsepower and torque characteristics 

50 

 
 
                                                           
Fuel cells on alcohol, methane  or SPF potentially provide high efficient and low pollutant engines, 
but the technology is currently relatively immature. 

Electrification  through  hybridisation  will  have  an  impact  on  engine  size  and  consequently  on  the 
type of engine and its fuel compatibility. A system approach is required for the development of such 
powertrains. Increased electric propulsion power does mean that engines can be further optimised 
to operate more efficiently and more cleanly within a smaller speed / load operating window as well 
as have lower transient requirements. 

Please note that wherever possible we have aligned the challenges (-) and opportunities (+) with the 
research and innovation needs in the tables below. 

51 

 
 
Table 12 - LDV summary table of R&I needs 

LDV 
Fuel category 

Natural gas 

Fuel 

Powertrain 

Challenges(-) & opportunities(+) 

R & I needs 

Compressed 
natural  gas,  bio-
methane 
or 
methane (CNG) 

engines 
SI 
optimised  for 
gas operation 

- Methane leakage 

+ Potential for efficiency improvements in Low and  High Pressure 
Direct Injection of CNG relative to incumbent CNG systems 
+  Further  engine  thermal  efficiency  improvements  of  around  5% 
through  synergies  of  high  octane  with  downsizing  in  real  world 
driving conditions 

SI lean 

+  Further  reduction  of  tail  pipe  pollutant  emissions  due  to  lower 
engine out emissions.  

+ On-board storage improvements through conformable, cheaper, 
lightweight solutions 
-  Ignition  system  and  control  to  robustly  initiate  combustion  and 
maintain  good  combustion  stability  at  very  lean  conditions  to 
ensure low engine out NOx emissions 

-  Appropriate and cost-effective  aftertreatment  systems to meet 

regulation 

- Effective air handling and  load control  

+ Significantly increase the engine thermal efficiency and therefore 
CO2  emissions  estimated  at  10-20%  relative  to  incumbent  CNG 
systems 
+ Synergies with increased electrification 

Liquid 
Petroleum Gas 

LPG, BioLPG 

SI 

+ High Pressure Direct Injection of LPG 

- Measurement of evaporative emissions to check if there is a 
problem, and research on control measures if necessary 
+ Dedicated gas LPDI and HPDI systems 

+  More  dedicated  CNG  engine  and  combustion  system 
designs 
+  New  components  for  high  efficiency  and  performance  SI 
engines,  such  as  direct  injectors,  electronic  regulators,  gas 
quality sensors and control strategies 
+ Better combustion and after treatment control strategies 
+  Optimised  TWC  chemistries  to  reduce  tailpipe  pollutants 
and methane further 
+  Conformable  CNG  cylinders  development  and  vehicle 
integration 
-  Development  of  advanced  ignitions  systems  such  as  fully 
controllable multiple spark ignition, corona, plasma etc 

lean  burn  gas  engines  with  advanced 

-  Dedicated 
aftertreatment systems  
-  Fast  response  and  variable  air  handling  systems  such  as 
electric  superchargers  with  appropriate  control  systems  to 
ensure good driveability  
+Dedicated  combustion,  fuelling  and  air  handling  system 
design  

+  Fully  optimise  and  integrate  the  engine  with  the  electric 
propulsion system (hybridisation, range extender etc)  

+  Vehicle  with  a  dedicated  High  Pressure  Direct  Injection 
spark ignition engine running on LPG/bioLPG  (with optimized 
compression  ratio,  injection  strategies,  use  of  EGR  and  any 
other measure directed to improve engine efficiency such as 

52 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Esters, ethers & 
alcohols 
Esters, ethers & 
alcohols 

FC 

SI 

Methanol 

Ethanol, 
methanol, 
butanol 
and 
other alcohols or 
blends 

+ Light weighting of the on-board fuel storage equipment  

+ Potential to have FC efficiencies  while using liquid fuels  making 
implementation much simpler than hydrogen 
- Mature technology when within EN228. No issues reported  
- Largely mature technology when used blended with gasoline up 
to E85 equivalent  
-Gasoline substitution worsens current unbalance 
+  Further  engine  thermal  efficiency  improvements  of  around  5% 
through  synergies  of  high  octane  with  downsizing  in  real  world 
driving conditions when optimised for higher blends levels such as 
E85. (Not Flex Fuel Vehicle) 

+  Thermal  efficiency  improvement  through  lean  combustion  with 
appropriate  NOx  control  as  main  powertrain  or  for  hybrid 
application  

lean operation) 
+  Injection  system  for  LPG/bioLPG  direct  injection  which 
prevents vapour lock under hot conditions 
+  Light  weight  fuel  tank  for  LPG/bioLPG  in-vehicle  storage 
with a shape suitable to be integrated as a conventional tank 
(e. g. under the vehicle trunk) 
+ Fuel cells using low carbon synthetic and fossil fuels 

+  Dedicated  fully  optimised  high  alcohol  blend  engine  and 
combustion system designs 
+Improved combustion and after treatment control strategies 
(incl. 
for  currently  non-regulated  emissions  such  as 
aldehydes) 

+  Fully  optimise  and  integrate  the  engine  with  the  electric 
propulsion system (hybridisation, range extender engine) 
+ Bi-fuel SI vehicles (octane on demand) using higher octane 
biofuels  in  conjunction  with  lower  octane  carbon  footprint 
fossil or synthetic fuels 

53 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5.1.2  HDVs 
Methane based gases in either compressed (CNG) or liquefied (LNG) form are currently considered 
as the main alternative fuel for the HDV sector (which is powered by CI engines). Dual fuel CI engines 
(engines  capable  of  running  on  diesel  or  CNG/LPG  with  diesel  pilot  in  this  case),  however,  do  not 
currently  meet  Euro  VI  emission  limits.  Significant  research  effort  into  advanced  injection  systems 
and /or  aftertreatment systems  that can operate under low temperature conditions  is required to 
overcome this issue. There is also potential for a better utilisation of these alternative fuels leading 
to  increased  engine  efficiency  through  the  development  of  high  pressure  direct  injection  (HPDI). 
HPDI  systems  are  under  development  and could  deliver  dual  fuel  engines  with  a  high  substitution 
rate  for  diesel  (90%)  and  characteristics  similar  to  current  diesel  engines  including  efficiency.  
Methane tailpipe emissions, which currently exceed EURO VI limits, are being addressed, but remain 
a concern  for the  rest of the  fuel chain.  Direct  injection in SI gas engines  could improve efficiency 
and tank-to-wheel (TTW) GHG emissions of such engines, approaching CI engine technology, while 
meeting EURO VI emissions limits due to the possibility of significantly reducing methane slip.  

Engine technology is currently commercially available for DME and ED95 combustion systems, which 
provide alternatives to CNG/LNG technology. While these technologies meet EURO VI emission limits 
and have efficiency similar to diesel engines,  further research into engine  efficiency improvement, 
pollutant  control  and  end-fuel  specifications  could  yield  further  improvements.  The  emission  of 
currently non-regulated emissions such as aldehydes needs further research. 

Similarly to LDVs, Synthetic Paraffinic Fuels represent a drop-in solution which could be adopted by 
the  existing  fleet,  however  their  cost  and  benefits  in  terms  of  improved  efficiencies  and  reduced 
pollutants need to be further researched and understood. 

In the longer term fuel cells fuelled by alcohols or other alternative fuels could be of interest, also 
for ancillary power supply. 

Another area for R&I is the development of high efficiency, low pollutant and low cost engines for 
use in hybridisation / range extender applications.  

54 

 
 
Table 13 - HDV summary table of R&I needs 

HDV 
Fuel category 
Natural gas 

Fuel 
Compressed 
of 
liquefied  natural  gas, 
bio-methane 
or 
methane (CNG, LNG) 

Powertrain 
SI 
engines 
optimised  for  gas 
operation 

Challenges(-) & opportunities(+) 
+Mature technology that is commercially available 
- Risk of methane slip / leakage from the fuelling system 

+ Increase engine thermal efficiency, but unlikely to reach 
current diesel engine levels 
+ Further reduction of tail pipe pollutant emissions due to 
lower engine out emissions 

SI lean 

+  On-board  storage  improvements  through  conformable, 
cheaper, lightweight solutions 
- 

Ignition  system  and  control 
initiate 
combustion  and  maintain  good  combustion  stability  at 
very  lean  conditions  to  ensure  low  engine  out  NOx 
emissions 

to  robustly 

R & I needs 

limit 
-  Specific  hardware  and  control  strategies  to 
evaporative  methane  emissions  from  the  fuel  system  and 
crankcase 

+  Dedicated  CNG/LNG  engine  and  combustion  system 
designs  
+ Better combustion and after treatment control strategies 
+  Optimised  TWC  chemistries  to  reduce  tailpipe  pollutants 
and methane further 
+  New  components  for  high  efficiency  and  performance  SI 
engines,  such  as  direct  injectors,  electronic  regulators,  gas 
quality sensors and control strategies 
+ Cheaper and more space efficient (e.g. conformable) LNG 
tanks development and vehicle integration 
-  Advanced  ignitions  systems  such  as  fully  controllable 
multiple spark ignition, corona, plasma, etc 

-  Appropriate and cost-effective aftertreatment systems to 

meet regulation 

- Effective air handling and  load control  

- Advanced aftertreatment systems for dedicated lean burn 
gas engines  
-  Fast  response  and  variable  air  handling  systems  such  as 
electric  superchargers  with  appropriate  control  systems  to 
ensure good driveability  

+  Significantly  increase  the  engine  thermal  efficiency  of 
about  10-20%  relative  to  SI  gas  engine,  reaching  diesel 
levels of efficiency 

+Dedicated  combustion,  fuelling  and  air  handling  system 
design  

+ Potentially well suited to being combined with increased 
electric propulsion (Plug in hybrid, range extender)  

+  Fully  optimise  and  integrate  the  engine  with  the  electric 
propulsion system (Plug in hybrid, range extender)  

CI - Dual Fuel 

-  Methane  tailpipe  emissions  exceed  EURO  VI 

limits 

- Low CH4 combustion system or CH4 catalysis. 

55 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
currently with HPDI in development to solve this issue 
-  Methane  catalysis  at  low  temperatures  experienced  at 
regulated test procedures 
+ HPDI technology 
+ Multifuel capabilities to bridge fuel transition 
+ Further thermal efficiency improvements  
+ Increased gas replacement factors 
+  On-board  storage  improvements  through  conformable, 
cheaper, lightweight solutions  

+ Advanced fuel injection systems (incl. high pressure direct 
injection  –  HPDI),  regulation  components,  gas  quality 
sensing and control strategies 
+ Advanced aftertreatment systems at competitive cost 
+  Cheaper  and  more  space  efficient  (e.g.  conformable) 
zero-vent LNG tanks development and vehicle integration” 

Liquid 
Petroleum Gas 

LPG, BioLPG 

SI 

+  Improved  engine  efficiency  through  dedicated  engine 
design with direct injection systems 

+ Further reduction of tail pipe pollutant emissions due to 
lower engine out emissions 
+  Significant  thermal  efficiency  through  lean  combustion 
reaching diesel levels with appropriate NOx control as main 
powertrain or for hybrid application 
+  On-board  storage  improvements  through  conformable, 
cheaper, lightweight solutions 

Esters,  ethers 
& alcohols 

DME, OME 

CI (incl. LTC etc.) 

technology, 

-  DME  engines  are  mature  EURO  VI 
commercially available through Volvo  
+  Lack  of  PM  allows  further  NOx  reduction  and  /  or 
improved fuel economy 
+  Dedicated  fuel  injection  technology  and  control  might 
allow 
improvements  and 
pollutant emission reduction 
+  On-board  storage  improvements  through  conformable, 
cheaper, lightweight solutions 

thermal  efficiency 

further 

LPG/bioLPG 

running  on 

+  Vehicle  with  a  dedicated  direct  injection  spark  ignition 
engine 
 (with  optimized 
compression ratio, injection strategies, use of EGR and any 
other  measure  directed  to  improve  engine  efficiency  such 
as lean operation) 
+  Injection  system  for  LPG/bioLPG  direct  injection  which 
prevents vapour lock under hot conditions 
+  Advanced  aftertreatment  chemistries  and  systems  at 
competitive cost 
+ Integration of LPG/bioLPG engine in a hybrid vehicle 

+  Light  weight  fuel  tank  for  LPG/bioLPG  in-vehicle  storage 
with  a  shape  suitable  to  be  integrated  as  a  conventional 
tank (e. g. under the vehicle trunk) 

+  Dedicated  and  optimised  DME  combustion,  fuel,  control 
and  aftertreatment  systems  with  the  aim  to  even  further 
improve TTW GHG and pollutant emissions  

+ Light weight fuel tank for DME (similar to LPG) in-vehicle 
storage  with  a  shape  suitable  to  be  integrated  as  a 
conventional tank (e. g. under the vehicle trunk) 

56 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   
Esters, ethers & 
alcohols 

Ethanol,  methanol, 
butanol  and  other 
alcohols or blends 

SI, SI lean 

- Early stage research at MIT, Ghent University  
- Driveability and emissions control 
- Potential for non-regulated aldehyde emissions 

+  Significant  potential  was  demonstrated  during  early 
testing.  Further  more  detailed  testing 
is  required  to 
understand the detailed R&I needs 

Esters, ethers & 
alcohols 

Ethanol, Methanol 

low 

(incl. 

CI 
temperature 
combustion 
systems) 

Methanol 

CI Dual Fuel 

further 

+ Engine thermal  efficiency  matching or  exceeding that of 
CI diesel engines throughout the operating area 
+ Reduction of tail pipe NOx and PM emissions  
+  Dedicated  fuel  injection  technology  and  control  might 
allow 
improvements  and 
pollutant emission reduction 
+ Potentially well suited to being combined with increased 
electric propulsion (PHEV, Range Extender) 
-  Ethanol  with  an  ignition  improver  (ED95)  is  a  mature 
EURO VI technology for HDV applications (Scania) 

thermal  efficiency 

+  Dedicated  and  optimised  alcohol  combustion,  fuel, 
control  and  aftertreatment  systems  with  the  aim  to  even 
further improve TTW GHG and pollutant emissions. 
+  Lean  SI  system  development  with  specific  advanced 
ignition systems, aftertreatment and control systems  

+  Develop  high  efficiency,  low  pollutant  and  low  cost 
engines for use in hybridisation / Range Extender 
-    Suitability  of  other  alcohols.  Methanol  with  an  ignition 
improver (MD95) is under investigation at VTT 

+ Potential to demonstrate an optimised alcohol based fuel 
with appropriate additives in CI engine technology 
+ Reduction of tail pipe pollutant emissions  

+  Dedicated  and  optimised  alcohol  (with  an 
ignition 
enhancer)  combustion,  fuel,  control  and  aftertreatment 
systems  with  the  aim  to  even  further  improve  TTW  GHG 
and pollutant emissions  

+  A  single  liquid  fuel  diesel  alternative  that  makes  the 
infrastructure issue much easier 
- Currently very immature technology in HDV, but principle 
demonstrated  and  commercialised  in  shipping  and  in 
principle similar to NG Dual Fuel  

- Potential corrosion issues 

- Potential for non-regulated aldehyde emissions 

+  Dedicated  fuel  injection  technology  (HDPI)  and  control 
might allow further thermal efficiency improvements  
+  Multifuel  capabilities  to  bridge  fuel  transition  +  Engine 
thermal  efficiency  matching  or  exceeding  that  of  CI  diesel 
engines throughout the operating area 
+ Further reduction of tail pipe pollutant emissions due to 

is 

-  Significant  R&I  requirements  as  this  technology 
immature  
-  Need  for  research  to  assess  suitability  of  this  fuel  and 
technology for HDV sector 
-  Assess  corrosion  issue  and  develop  new  materials  / 
additives 
-  Assess  the  scale  of  aldehyde  emissions  &  aftertreatment 
option 
+ Optimised injection equipment for alcohol dual fuel  
applications 

+ Optimised combustion, aftertreatment & control systems 

57 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
SPF 

SPF 

Other 

lower engine out emissions.  
+ Lack of engine out PM allows further NOx reduction and / 
or improved fuel economy 

+  To  address  the  EU  imbalance  between  gasoline  and 
diesel demand. 

ignition  engines  using 

+ Naphtha or other higher volatility/ less processed fuels in 
compression 
low  temperature 
combustion  for  improved  efficiency  with  lower  emissions 
and WTW CO2 reduction 
+ Low temperature combustion in CI using higher volatility 
synthetic/low  carbon  e.g.  paraffinic  fuels  for  improved 
efficiency and reduced emissions 

58 

 
 
 
5.1.3  Rail 

The use of alternative fuels in ICE technology in rail is considered for those routes where overhead 
line  electrification  is  not  commercially  feasible  and  diesel  engines  are  used.  The  rail  sector  is 
currently  not  a  technology  leader  in  ICE  technology  and  fleet  turnover  is  generally  slow.  As  a 
consequence the sector relies heavily on adapted engines and other technology originally developed 
for  the  on  and  off-road  HDV  sector  and  hence  most  of  the  HDV  considerations  would  also  apply 
here. 

The main alternatives considered are LNG  and the increased use of biodiesel  and  SPFs (e.g. HVO).  
The  uptake  of  LNG  as  an  option  requires  the  engineering  of  new  locomotives  for  dedicated  LNG 
engine  or  dual-fuel  engines  since  this  option  is  not  suitable  for  existing  locomotive  retrofitting. 
Furthermore  significant  efforts  are  required  to  roll  out  dedicated  and  optimised  combustions 
systems for these fuel types as well the required aftertreatment systems meeting NRMM stage V. 

The use of  biodiesel  in engines  with blending up to 20%  (B20) is considered a mature technology, 
and  such  blending  does  not  require  significant  engine  modifications.  This  option  has  the  merit  of 
decreasing  soot  emissions,  but  may  increase  fuel  consumption  and  NOX  emissions,  requiring 
combustion control and aftertreatment systems.   

Increased levels of vehicle electrification enable engines to be optimised for one or a small number 
of  operating  conditions  where  it  is  most  efficient  as  is  the  case  in  range  extender  vehicles  for 
example.  Additional  efficiency  improvements  can  then  be  leveraged  by  utilising  the  unique 
properties such as octane level of alcohol and methane based fuels. 

59 

 
 
 
Table 14 - Rail summary table of R&I needs 

Rail 
Fuel category 
Esters 

Fuel 
Biodiesel 

Powertrain 
CI 

Natural  Gas  / 
alcohol 

LNG / methanol 

CI-DF 

for 

low 

acceptable  without 

Challenges(-) & opportunities(+) 
-  Cold-weather  characteristics  not  suitable 
temperature operation without fuel-line heaters. 
-  Current  knowledge  shows  an  increase  of  NOx  when  using 
biodiesel. 
+ Mature technology (US) - The use of B20 in railway engines 
is 
significant  engine 
modifications. 
+  B20  decreases  the  hydrocarbon  and  soot  emissions,  but 
may  increase  the  fuel  consumption  (engine  type,  tuning 
level).  
- Not suitable for existing locomotive retrofitting 
- Safety issues related to methane leakage  
+  HPDI  technology  developed  in  shipping  and  trucking  for 
both gas and alcohols would be equally suitable for rail 

requiring 

R & I needs 

-  Advanced  combustion  control  and  aftertreatment 
systems 
+  Combining  technologies  (bi-mode  trains)  to  improve 
fuel combustion efficiency and pollution reduction. 
+  Advanced  combustion  technologies  for  managing  NOx 
released during the combustion. 

+ Develop high  energy efficiency locomotive 
+  Engineering  new  locomotive  for  dedicated  LNG-gas 
engine or dual-fuel engines 
+ Combining propulsion system for energy saving 
+  Optimise  the  combustion  system  to  reduce  the  fuel 
consumption (automatic controlling devices) 

60 

 
 
 
 
 
 
 
 
 
 
 
 
5.1.4  Waterborne  
Large  scale  adoption  of  alternative  fuels  within  the  waterborne  sector  offers  the  possibility  of 
significant  reductions  in  airborne  pollutants  compared  to  the  heavy  fuel  oils  used.  The  two  main 
alternative  fuels  that  are  currently  considered  for  waterborne  applications  are  methane  and 
methanol. Both are currently commercially available and mainly used in dual fuel applications with 
gas oil used as a pilot injection to initiate combustion. Both methane-based fuels (LNG/LBG/PTL) and 
methanol could significantly reduce  SOx and PM emissions in particular, as well as NOx emissions. 
The  use  of  methanol  could  reduce  NOx  emissions  by  up  to  60%,  but  not  down  to  Tier-III  level. 
Further  research  should  be  focussed  on  increasing  the  methanol  /  gas  substitution  rates 
respectively,  engine  efficiency  and  further  reducing  pollutant  emissions,  including  eliminating 
methane  slip.  R&I  on  dedicated  high  efficiency  lean  combustion  engines  for  either  methane  or 
methanol  based  fuels  can  potentially  provide  higher  efficiency,  low  pollutant  and  GHG  emission 
solutions. 

Methane slip throughout the fuels chain is a concern for methane based fuels that warrants further 
research.  Technologies  for  methane  slip  reduction  need  to  be  incorporated  in  new  ship  designs. 
Exhaust gas recirculation (which improves combustion stability), the use of aftertreatment systems 
with  methane  oxidation  catalysts,  or  high-pressure  direct  injection  are  techniques  able  to  reduce 
methane slip.   

In the longer term fuel cells fuelled by alcohol, LNG/LBG/PTL or other alternative fuels could be of 
interest, for both propulsion and ancillary power supply. 

Better  storage  and  handling  solutions  and  bunkering  logistics  are  required  for  LNG  and  methanol. 
Wide  scale  uptake  of  either  fuel  is  hampered  by  the  limited  (global)  bunkering  provisions. 

61 

 
 
 
Table 15 - Waterborne summary table of R&I needs 

Waterborne Transport 
Fuel category 
Alcohols 

Fuel 
Methanol 

Powertrain  Challenges(-) & opportunities(+) 
CI-DF 

- Immiscible with marine fuels – cannot be used as blends. 
+  Reduces  emissions  of  PM  by  >80%  and  SOx  by  >90% 
depending on the substitution rate  
+  Already  used  as  main  fuel  in  an  adapted  marine  diesel 
engine with StenaLine. 

R & I needs 

+  Develop  engines  &  injection  equipment  allowing  increased 
methanol  (and  other  alcohols)  substitution  rates  or  have 
dedicated  methanol  engine  technology  that  meets  /  exceeds 
current  marine  oil  engine  efficiencies  at  low  CAPEX  cost  and 
low noxious emissions 

Natural gas 

LNG 

SI 

+ Reduces NOx emissions by up to about 60% 

+ Advanced aftertreatment systems (NOx) at competitive cost 

+  Methanol  and  solid  oxide  fuel  cell  (SOFC)  system  for 
ancillary power. 

-  Fuel  availability,  safety  issues  for  on-board  fuel  storage, 
handling systems. 
-  Possibility  of  abnormal  combustion  (methane  slip)  – 
sensitive to gas composition  
+  Waterborne  engines  using 
low  pressure  LNG  have 
emissions  below  NOx  limit  (IMO  Tier  III)  without  use  of 
exhaust gas treatment system 
+  Possibility  to  use  the  cooling  effect  of  LNG  vaporisation 
for  refrigeration  of  foods  (e.g.  fish  boats),  air  conditioning 
on-board, and other cooling effect carries 

+  Future  research  activities  on  larger  methanol-fuel  cells  on 
marine vessels. 
+  Tests  for  assessment  of  environmental  impacts  of  methanol 
and SOFC technology for shipping. 

+ New engine design for: load efficiency optimisation, reduction 
of methane slip, adaptation to variable gas composition. 
+ Emission control and energy efficiency measures for ships in 
the port area. 
+ Waste heat recovery from  propulsion engine  for overall fuel 
consumption management on ship.  
+ Investigation on ultrafine PM 
+  Fuel  handling  and  storage  (onboard  and  shore):  better 
storage solution (space, cost), bunkering logistics. 

CI-DF 

- Sensitive to gas composition  
- Higher NOx emissions than the lean burn type (SI). 

+  Fuel  flexible  engines  -  able  to  switch  between  fuels  in 

+ Improvement of energy efficiency of large vessels for coastal 
(increase  propulsion  efficiency  – 
and  seagoing  vessels 
combined  electric  propulsion, 
integrated  propeller-rudder 
configuration).  

62 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
sailing 

some  abnormal 
regions  or  when 
different 
combustion  or  leakages  occur.  Less  dependence  on  the 
availability  of  LNG  bunkering  facilities  when  sealing  in 
different regions. 

+  Advanced  injection  (HPDI)  and  combustion  systems  for 
greater efficiency 
+ Advanced optimised cylinder lubrication systems. 
+  Advanced  catalyst  system  for  aftertreatment  (NOx)  at 
competitive cost 
+  Investigation  on  the  impact  of  switching  fuel  on  emissions 
level and engine components.  
+ Numerical models for evaluating case by case the integration 
of energy efficiency systems in new ships designs.  
+ Developments in sensors, condition assessment and adaptive 
control  methods,  materials 
lubrication 
improvements 
+ Waste heat recovery from  propulsion engine  for overall fuel 
consumption management on ship. 

tribology  and 

63 

 
 
 
  
 
5.1.5  Aviation 
Aviation  strongly  relies  on  energy  dense  fuels.  While  radical  redesign  of  aviation  powertrains  is 
progressing, the sector is expected to remain highly dependent on drop-in fuels for at least the next 
30 years. Synthetic Paraffinic Fuels (SPFs) currently seem the most feasible alternative  fuel for the 
foreseeable  future.  Various  routes  to  synthetic  kerosene  are  already  technically  available  for 
commercial  aviation  and  up  to  other  20  are  currently  waiting  to  be  tested  and  approved  for  use. 
Important  areas  of  research  with  regards  to  the  use of  SPFs  in  aviation  include  assessment of  the 
impact on engine components, understanding blending limits and optima, and impact on pollutant 
emissions. In terms of energy efficiency, the gains that can be expected from using drop-in fuels are 
minimal (~2%), but there is an interesting potential for reduction of non-volatile particulate matter 
(nvPM) (up to 60% reduction in mass and 40% on PM number with a 50/50 blend35). Research is also 
focused  on  understanding  the  lower  limits  for  some  aromatics  species  and  sulphur  for  providing 
optimal performance while reducing SOx and PM emissions.  The effect of different blend levels of 
drop-in  fuels  on  parameters  like  combustion  temperature,  efficiency,  unburned  hydrocarbons  and 
black carbon are a subject of research, and could lead to different high altitude effects compared to 
conventional kerosene. Further research on the SPFs is needed in relation to chemical composition, 
allowable and optimal blending levels, and impact on pollutant emissions. Radical aircraft redesign 
could  lead  to  the  consideration  of  liquefied  methane  and  hydrogen  as  fuels  in  the  longer  term.

35 EC funded ITAKA project 

64 

 
 
                                                           
Table 16 - Aviation summary table of R&I needs 

Aviation 
Fuel category 
SPF  

Powertrain 
Turbofan 

Fuel 
FT-SPK, 
HEFA-SPK, 
FT-SKA  

Challenges(-) & opportunities(+) 
-  Unknown  real  blend  limits,  current  limit  related  with 
aromatics and sulphur content 
+ Similar composition to incumbent 
+ Mature technology once blended up to 50% v 
+ Blend ratio likely to be enlarged with better knowledge 
+ Lower pollutants (PMs up to -60%, and S)  
+ Potential (lower?) climate effect at altitude 

SPF 

SIP 

Turbofan 

SPF 

ATJ 

Turbofan 

SPF 

HEFA+ 

Turbofan 

- blend limits, probably cannot go higher 
- fuel composition different to incumbent 
+ Mature technology once blended up to 10% v 
+ Lower pollutants (PMs up to -60%, and S)  
+ Potential lower NOx emissions with better design 
+ Potential (lower?) climate effect at altitude 
- blend limited by fuel gauging system performance 
- fuel composition different to incumbent 
+ Mature technology once blended up to 30% v 
+ Lower pollutants (PMs up to -60%, and S)  
+ Potential (lower?) climate effect at altitude 

- Fit for purpose not certified 
- max (foreseen) blend 10% v 
- Mature (fuel) technology 
+ Lower pollutants (PMs and S)  
+ Potential (lower?) climate effect at altitude 

identical  conditions,  and  the  effects 

R & I needs 
+to  know  what  is  maximum  blend  limit,  particularly  with  regards  to 
minimum aromatics and sulphur content  
+need to know effects on maintenance operations (i.e. in flight water 
generation) with long term use 
+to know the effects on key emissions varying properties of the fuel, 
engines,  operations  and  atmospheric  conditions  to  better  define  the 
extent of the benefits of the use. 
+Integrated,  fuel-centric  research,  investigating  the  effects  of  fuel 
composition  on  operations  and  emissions,  where  fuel  is  varied  for 
identified.  Such 
otherwise 
research should include fuels outside the current experience base for 
fossil fuels, to identify risks and opportunities. 
+Support testing at ASTM for enabling more alternatives. 
+Integrated,  fuel-centric  research,  investigating  the  effects  of  fuel 
composition  on  operations  and  emissions,  where  fuel  is  varied  for 
otherwise 
identified.  Such 
research should include fuels outside the current experience base for 
fossil fuels, to identify risks and opportunities. 
+Support testing at ASTM for enabling more alternatives. 
+Integrated,  fuel-centric  research,  investigating  the  effects  of  fuel 
composition  on  operations  and  emissions,  where  fuel  is  varied  for 
identified.  Such 
otherwise 
research should include fuels outside the current experience base for 
fossil fuels, to identify risks and opportunities. 
+Support testing at ASTM for enabling more alternatives. 
+Needs  to  better  understand  the  blend  limits  and  the  properties  for 
production and distribution  
+Integrated,  fuel-centric  research,  investigating  the  effects  of  fuel 
composition  on  operations  and  emissions,  where  fuel  is  varied  for 
identified.  Such 
otherwise 
research should include fuels outside the current experience base for 
fossil fuels, to identify risks and opportunities. 

identical  conditions,  and  the  effects 

identical  conditions,  and  the  effects 

identical  conditions,  and  the  effects 

65 

 
 
LNG 

LNG 

Turbofan 

ratio 

requires 

-  not  drop-in,  volume/weight/energy 
different aircrafts, logistics facilities 
-  Increased  water  vapour  emission  by  40%  (potential 
climate impact) [AHEAD] 
- uncertain climate effect (balance) at altitude 
+ Decrease of CO2 by 25% [AHEAD] 
+ Decrease of NOx by 80% [AHEAD] 
+ Zero PM emissions  [AHEAD] 
+ better thermal efficiency  

+ Support testing at ASTM for enabling more alternatives 
+  Breakthrough  research  on  airframe  and  combination  with 
electrification.  

66 

 
 
 
 
5.2  Implementation plan 
Reducing GHG emissions in transportation consists of two main elements, namely: 

1.  The  availability of cost-effective  sustainable  low  carbon  alternative  energy /  fuels  (well-to-

tank - WTT); 
Improved efficiency in real world utilisation (tank-to-wheel - TTW).  

2. 

This report deals with the potential impact of alternative fuels on the latter, as well as their potential 
impact  on  emissions  affecting  air  quality.      Decarbonisation  will  depend  on  the  full  well-to-wheel 
implications of alternative fuel use, and will need to rely on low carbon and renewable fuels, while 
alternative fossil-derived fuels could help address in the interim air quality and energy diversification 
issues. 

Figure  15  provides  a  possible  high  level  timeline  for  implementation  of  promising  alternative  fuel 
and  powertrain  combinations.  The  R&I  needs  for  each  transport  sector  supporting  effective 
implementation are summarised below and detailed in Table 12 to Table 16.  

A  number  of  alternative  fuel  options  could  be  deployed  in  each  mode  with  benefits  in  terms  of 
optionality  and  energy  diversification.  LDVs  and  rail  also  have  the  option  of  increased  electrified 
propulsion systems through on-board storage of electricity or hydrogen and overhead electrification 
lines, which are dealt with in the STRIA on electric mobility. 

Figure 15 - Overview and timescales of most promising alternative fuel options 

67 

LDVsHDVsWaterborneAviationTransport ModesImproved use of alcohols, ethers and gases in SI Now20302050SPF in conventional SI/CISPF in LTC engine for hybrid tech Gaseous fuels in HPDI –mono fuelAlcohols + other AFs in Fuel CellsAlcohols and ethers in CI & LTC systems -> HPDI (DF)Alcohols and gaseous in DF CIIntegration with hybridisation tech Gases in SI engines -> HPDI (DF)  high eff gas enginesIntegration with hybridisation tech RailIncreased biofuels, SPFs Integration with hybridisation tech Dedicated high eff gas & methanol enginesAlcohols + other AFs in Fuel CellsBiodiesel & SPF in CI & LTCHEFA+ and SPFs in TurboFans 
 
 
 
 
5.3  Synthesis of R&I agenda 
The main alternative fuels are gases, alcohols, ethers and drop-in SPFs with specific technology R&I 
requirements highlighted in the tables and text in section 5.1 for each transport mode. The rest of 
this section provides a synthesis of the R&I agenda in support of the implementation plan above. 

LDVs 

Increase  the  uptake  of  alcohols,  ethers  and  gases  in  spark  ignition  (SI)  engines  (taking  into 
consideration  their  potential  for  GHG  savings),  while  improving  their  use  by  optimising  injection, 
combustion,  aftertreatment  systems  and  their  control.  For  compression  ignition  (CI)  engines  the 
uptake of more biodiesel and especially SPF (again taking into consideration their potential for GHG 
savings) would benefit from optimisation of the engine and related technology. 

Direct  injection  in  gas  SI  engines  has  the  potential  to  further  improve  the  TTW  GHG  emissions  of 
such  engines.  Both  SI  &  CI  gas  engines  can  achieve  higher  efficiency  combustion  systems,  such  as 
lean combustion, controlled auto-ignition (CAI) for SI engines and homogeneous charge compression 
ignition  (HCCI)  and  all  manner  of  low  temperature  combustion  (LTC)  systems  for  CI  engines. 
Implementation of such systems would significantly benefit from narrower fuel specifications, which 
alternative fuels could provide. 

Furthermore, these combustion systems tend to be best suited to and most efficient at a narrower 
operating window both in terms of speed/load as well as their transient capability. Increased levels 
of electrification can facilitate this by effectively filling in the operating window gaps. A strong R&I 
focus  on  optimisation  of  the  complete  system  with  increased  levels  of  electrification  is  therefore 
required. 

 In the longer term fuel cells fuelled by alcohols or other alternative fuels could be of interest.  

HDVs 

Alcohol and ether based CI combustion systems are commercially available, but not widespread in 
part due to lack of infrastructure. There is further development potential in the better utilisation of 
these fuels with a particular focus on high efficiency  high pressure direct injection (HPDI) dual fuel 
systems as well as LTC systems.  

Direct injection in SI gas engines could improve efficiency and tank-to-wheel (TTW) GHG emissions of 
such engines, approaching CI engine technology, while meeting EURO VI emissions limits due to the 
possibility of significantly reducing methane slip. 

High efficiency combustion systems that operate in a narrower window both in terms of speed/load 
as well as their transient capability could be developed for HDVs for lighter duty cycles i.e. shorter 
distances, lower speeds and lower carrying capacity. Increased levels of electrification can facilitate 
this  by  effectively  filling  in  the  operating  window  gaps.  A  strong  R&I  focus  on  optimisation  of  the 
complete system with increased levels of electrification is therefore required for these vehicles.  

In the longer term fuel cells fuelled by alcohols or other alternative fuels could be of interest, also for 
ancillary power supply.  

68 

 
 
For road transport the immediate R&I needs are summarised comprehensively in ERTRAC’s ”Energy 
carriers for Powertrains” [6]. 

Rail 

Where overhead  line  electrification  is  not  commercially  feasible  the  rail  sector  could  benefit  from 
the  increased  use  of  blended  biofuels  and  SPFs.  Typically  this  sector  relies  heavily  on  adapted 
engines  and  other  technology  originally  developed  for  the  on  and  off-road  HDV  sector  and  hence 
most of the HDV considerations above would also apply here, including gas engines that could be of 
interest  in  future  locomotives.  The  availability  of  an  (overhead)  charging  infrastructure  and  well-
known  duty-cycles  suggests  that  the  interaction  between  ICE  and  electrification  technology  is 
particular  promising.  In  the  longer  term  fuel  cells  fuelled  by  alcohol,  LNG/LBG/PTL  or  other 
alternative fuels could be of interest.  

Waterborne 

Large  scale  adoption  of  alternative  fuels  within  the  waterborne  sector  offers  the  possibility  of 
significant  reductions  in  airborne  pollutants  compared  to  heavy  fuel  oils.    Methane-based  gas 
(LNG/LBG/PTL)  and  methanol  in  dual  fuel  applications  are  commercially  available  and  would  be 
adopted more widely if greater fuelling infrastructure were available, and supply chains, storage and 
engines could be further optimised to eliminate methane slip, improve efficiency and emissions.  

High  efficiency  combustion  systems  that  operate  on  a  single  fuel  in  a  narrower  window  both  in 
terms of speed/load as well as their transient capability could be developed for some ship engines.  

In the longer term fuel cells fuelled by alcohol, LNG/LBG/PTL or other alternative fuels could be of 
interest, for both propulsion and ancillary power supply.    

Aviation 

SPFs are the most feasible alternative fuel for the foreseeable future for aviation. Various end-fuels 
are  under  consideration,  and  research  will  focus  on  assessing  impact  on  engine  components, 
understanding blending limits and optima, and impact on pollutant emissions. 

5.3.1  Roles and resources 
The automotive industry and its suppliers are major investors in innovation, to the tune of around 40 
billion  Euros  according  to ACEA36.  Much  innovation  and  related  spending  has  gone  into  improving 
vehicle efficiency to meet lower vehicle CO2 emissions limits. 

Alternative fuels should play a major role in reducing CO2 emissions from transport by substituting 
fossil  fuels,  but  the  role  they  can  play  in  reducing  tailpipe  CO2  emissions  by  allowing  engine 
efficiency  improvements  and  more  efficient  hybridisation  also  need  to  be  recognised  for  these 
benefits  to  be  realised.    Recognising  and  realising  these  benefits  requires  a  greater  interplay 
between fuel suppliers and the automotive industry, so that emissions reduction from fuel use and 
from  vehicle  operation  are  no  longer  seen  as  separate  and  the  synergies  between  the  two  are 
exploited. 

36 http://www.acea.be/uploads/press_releases_files/POCKET_GUIDE_2015-2016.pdf 

69 

 
 
                                                           
Integration will  be  a  feature  of  future  research  and  innovation,  stressing  the  importance of  cross-
industry  and  cross-country  collaborations.  European  Framework  programmes  are  therefore  ever 
more relevant in this context. So, is also the continued development of industry research roadmaps 
that specifically incorporate alternative fuel and vehicle interactions. Harmonisation too has a role to 
play  in  effectively  delivering  a  clean  transport  system  in  Europe,  for  example  through  fuel 
specifications  that  enable  higher  levels  of  alternative  fuels  to  be  delivered  to  the  market.  The 
European  Commission  and  cross-industry  groups  will  continue  to  be  instrumental  in  this  area. 
Research will however also need to deliver technologies which are able to deliver best results under 
variable conditions e.g. varying blend levels across Europe. 

Policy  will  need  to  play  an  important  role  in  steering  the  research  towards  meeting  specific 
environmental objectives, as it has successfully done in the case of vehicle CO2 emissions and HDV 
noxious emissions.  So, the role of policy will be  critical in sending signals to the  market  about  the 
expected  importance  of  alternative  fuels.  This  will  drive  the  private  sector  to  allocate  research 
resources  to  alternative  fuels,  which  will  be  complemented  by  national  and  European  funding  to 
support innovation in the area. 

70 

 
 
6  References 

DG 

[1] 
http://ec.europa.eu/taxation_customs/index_en.htm# 

“Excise 

TAXUD 

(2015) 

duty 

tables”. 

Available 

at: 

[2]  COWI  for  DG  MOVE  (2015)  “State  of  the  Art  on  Alternative  Fuels  Transport  Systems  in  the 
European  Union”.  Available  at:  http://ec.europa.eu/transport/themes/urban/studies/doc/2015-07-
alter-fuels-transport-syst-in-eu.pdf 

[3] IEA (2014) “Ethanol and biodiesel consumption in road transport by region in the New Policies 
Scenario”.  

EurObserv'ER 

[4] 
er.org/category/all-biofuels-barometers/ 

(2015) 

“Biofuels  barometer”.  Available 

at:  http://www.eurobserv-

[5] EC (2015) “EU energy in figures - Statistical pocket book 2015” 

ERTRAC 

[6] 
http://www.ertrac.org/uploads/documentsearch/id32/2014-03-
12_Roadmap_Energy_Carriers_for_Powertrains.pdf   

“Energy 

carriers 

for 

powertrains”, 

27/2/2014, 

[7]  ERTRAC  “Future 
http://www.ertrac.org/uploads/documentsearch/id42/2016-06-
09_Future%20ICE_Powertrain_Technologies_final.pdf  

light  and  heavy  duty 

ICE  powertrain 

technologies”,  9/6/2016, 

 [8]  EMSA  (2015)  “Study  on  the  use  of  ethyl  and  methyl  alcohol  as  alternative  fuels  in  shipping”. 
Available  at:  http://www.emsa.europa.eu/news-a-press-centre/external-news/item/2726-study-on-
the-use-of-ethyl-and-methyl-alcohol-as-alternative-fuels-in-shipping.html 

[9]  European  biofuels    (2014)  “European  Biofuels  Technology  Platform  (EBTP)  -  -  an  Overview”. 
Available at: http://biofuelstp.eu/overview.html 

[10]  EC  (2013)  “Clean  Power  for  Transport:  a  European  alternative  fuels  strategy”.  Available  at: 
http://eur-lex.europa.eu 

2015”. 
[11] 
http://www.iea.org/topics/transport/publications/railwayhandbook2015/ 

Handbook 

“Railway 

(2015) 

IEA 

Available 

at: 

[12]  EEA  (2013)  “EMEP/EEA  emission  inventory  guidebook  2013  –  Navigation”.  Available  at: 
www.eea.europa.eu/publications 

[13]  Clean  North  Sea  Shipping  Project  (2013)  “LNG  fuelled  ships  for  clean  air  in  harbours  Greener 
Shipping in the Baltic Sea”. Available at: http://cnss.no/ 

[14]  Clean  North  Sea  Shipping  Project  “Cleanship  –  final  report”.  Available  at:  http://www.clean-
baltic-sea-shipping.com/uploads/files/CLEANSHIP_final_report_for_download.pdf 

[15]  DNV  GL  –  Maritime 
https://www.dnvgl.com/maritime/ 

(2016) 

“Engines 

for 

gas-fuelled 

ships”.  Available  at: 

71 

 
 
[16]  DNV  GL  –  Maritime  (2014)  “LNG  as  ship  fuel.  Alternative  fuels  for  shipping”.  Available  at: 
https://www.dnvgl.com/maritime/    

[17] TEN-T Projects (2013) “LNG infrastructure of filling stations and deployment in ships”. Available 
at:  https://ec.europa.eu/inea/en/ten-t/ten-t-projects/projects-by-country/multi-country/2010-eu-
21112-s 

[18] EU (2016) “Significant LNG fuelled Ships”. Available at: https://lngforshipping.eu 

[19]  EC  (2015)  “Consultation  on  an  EU  strategy  for  LNG  and  gas  storage”.  Available  at: 
https://ec.europa.eu/energy 

[20]  JRC  (2016)  “Alternative  Fuels  for  Waterborne  and 
http://publications.jrc.ec.europa.eu/repository/bitstream/JRC100405/inland%20and%20Waterborn
e%20waterways%20exploratory%20work%20on%20alternative%20fuels_kamaljit%20moirangthem_
final.pdf 

Inland  Waterways”.  Available  at: 

EC 

[21] 
http://ec.europa.eu/clima/policies/transport/shipping/index_en.htm 

“Reducing 

emissions 

(2016) 

from 

the 

shipping 

sector”.  Available 

at: 

[22]  EPA 
http://www.epa.nsw.gov.au/ 

(2014)  “Reducing  Emissions 

from  Non-road  Diesel  Engines”.  Available  at: 

[23] UIC (2012) “Moving towards sustainable mobility”. Available at: http://www.uic.org 

[24]  Railway  Technology  (2013)  “Hydrail  and  LNG:  the  future  of  railway  propulsion”.  Available  at: 
http://www.railway-technology.com/ 

[25]  Railway  Technology  (2013)  “Russian  railways:  connecting  a  growing  economy”.  Available  at: 
http://www.railway-technology.com/ 

[26] IMO (2015) “Third IMO GHG Study 2014”. Available at: http://www.imo.org/ 

IEA  (2015)  “CO2  Emissions  From  Fuel  Combustion  Highlights  2015”.  Available  at: 

[27] 
https://www.iea.org/publications/freepublications/publication/co2-emissions-from-fuel-
combustion-highlights-2015.html 

[28]  EMSA  (2016)  “Study  on  the  use  of  ethyl  and  methyl  alcohol  as  alternative  fuels  in  shipping”. 
Available  at:  http://www.emsa.europa.eu/news-a-press-centre/external-news/item/2726-study-on-
the-use-of-ethyl-and-methyl-alcohol-as-alternative-fuels-in-shipping.html 

[29]  IEA  (2013)  “Alternative  Fuels  for  Marine  Applications”.  Available  at:  http://www.iea-
amf.org/app/webroot/files/file/Annex%20Reports/AMF_Annex_41.pdf 

[30]  ATAG 
http://www.atag.org/component/downloads/downloads/203.html 

(2012)  “A  sustainable 

flightpath  towards  reducing  emissions”.  Available  at: 

[31]  ICAO  (2013)  “ICAO  environmental  report  2013.  Aviation  and  climate  change”.  Available  at: 
http://cfapp.icao.int/Environmental-Report-
2013/files/assets/common/downloads/ICAO_2013_Environmental_Report.pdf 

72 

 
 
[32]  Steve  Csonka  (2016)  “CAAFI  –  CORE-JetFuel  Cooperation  Workshop”.  Available  at:  www.core-
jetfuel.eu 

[33]  ASTM  (2016)  “ASTM  D7566-16,  Standard  Specification  for  Aviation  Turbine  Fuel  Containing 
Synthesized Hydrocarbons”. Available at: http://www.astm.org/Standards/D7566.htm 

[34] ITAKA project (2016) “Press release. ITAKA provides sustainable fuel for worldwide’s first biojet 
http://www.itaka-
supply 
project.eu/Shared%20Documents/20160122_ITAKA_airportusage_start.pdf 

at  Oslo 

Available 

Airport”. 

hydrant 

system 

via 

at: 

[35]  Greenaironline  (2016)  “United  begins  regular  use  of  commercial-scale  volumes  of  AltAir's 
at: 
flights 
biofuel 
renewable 
http://www.greenaironline.com/news.php?viewStory=2208 

Available 

LAX”. 

from 

jet 

on 

[36]  Ecofys 
http://www.ecofys.com/files/files/ecofys-2015-accounting-methods-for-biojet-fuel.pdf 

(2016)  “Accounting  methods 

fuel.  Final 

for  biojet 

report”.  Available  at: 

[37] EU Biofuels Flightpath (2016) “2 million tons per year: A performing biofuels supply chain for EU 
at: 
aviation”. 
https://ec.europa.eu/energy/sites/ener/files/20130911_a_performing_biofuels_supply_chain.pdf 

Available 

Road 

[38] 
https://www.fuelseurope.eu/uploads/images/update2016/Graphs_FUELS_EUROPE%20_2016_WEB
%20(9)_756.jpg 

demand 

fuel 

the 

in 

EU, 

[39] EC communication (2014), A policy framework for climate and energy in the period from 2020 
to 
http://eur-lex.europa.eu/legal-
at: 
content/EN/TXT/PDF/?uri=CELEX:52014DC0015&from=EN 

Available 

2030, 

as 

at: 
report, 
[40]  Methanol 
http://methanol.org/getdoc/a9af8c29-e199-4854-b1c7-4e869991aaa7/FCBI-Methanol-Marine-Fuel-
Report-Final.aspx  

(2015).  Available 

a  marine 

energy 

FCBI 

fuel 

73 

 
 
 
 
 
 
 
 
 
7  Appendix 

7.1  Table of acronyms 
BEV 

Battery Electric Vehicle  

LPG 

Liquefied Petroleum Gas 

BTL 

CAI 

CI 

Biomass-to-Liquid 

MGO 

Marine Gas Oil 

Controlled Auto Ignition 

MTBE 

Methyl Tert-Butyl Ether 

Compression Ignition 

NEDC 

New European Drive Cycle 

CI-DF 

Compression Ignition Dual Fuel 

NG 

Natural Gas 

CNG 

Compressed Natural Gas 

NOx 

Nitrogen oxides 

CO2eq 

Carbon Dioxide equivalent 

OEM 

Original Equipment Manufacturer 

CO 

DF 

Carbon monoxide 

Dual Fuel  

DME 

Di-Methyl Ether  

ETBE 

Ethyl Tert-Butyl Ether 

FAME 

Fatty Acid Methyl Ester 

FC 

FT 

Fuel Cell 

Fischer-Tropsch 

GHG 

Greenhouse Gas 

GTL 

Gas-to-Liquid 

HCCI 

Homogeneous 
Charge Ignition 

Compression 

HDV 

Heavy Duty Vehicle 

(nv)PM 

(non-volatile) Particulate Matter 

PN 

Particulate number 

PHEV 

Plug-in Hybrid Electric Vehicle 

RDE 

RED 

REx 

SI 

SI lean 

STRIA  

SIP 

SPK 

Real Driving Emissions 

Renewable Energy Directive 

Range Extender engine 

Spark Ignition 

dedicated  spark  ignition  engine 
running with excess air 

Strategic  Transport  Research  and 
Innovation Agenda 

Synthetic Iso-Paraffinic 

Synthetic Paraffinic Kerosene 

HEFA 

Hydrotreated  Esters  and  Fatty 
Acids 

TWC 

Three-Way Catalyst 

HFO 

Heavy Fuel Oil 

HVO 

Hydrotreated Vegetable Oil 

LBG 

LDV 

LNG 

Liquefied BioGas 

Light Duty Vehicle 

Liquefied Natural Gas 

TTW 

WTT 

Tank To Wheel 

Well To Tank 

WTW 

Well To Wheel 

74 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7.2  Technical glossary 

Description 

Technology  and 
fuels 
Ethanol and derivatives 
Ethanol 

fuel,  which  can  be 
Alcohol 
produced 
renewable 
from 
agricultural  feedstocks.  Can  be 
blended  to  very  high  levels  into 
gasoline 
internal 
for  use 
combustion engine vehicles. 

in 

ETBE 

ED95 

Ethyl Tert Butyl Ether 
fuel 
An  ether  used  as  a 
the 
oxygenate,  produced  via 
chemical reaction of ethanol and 
isobutylene.  Most  often  used  as 
oxygenate to gasoline. 
An  ethanol-based  blend  of  95% 
ethanol 
ignition 
improving  additives  for  adapted 
diesel engines.  

and 

5% 

Methanol and derivatives 
MTBE 

Methyl Tert Butyl Ether 
An  ether  used  as  a 
fuel 
the 
oxygenate,  produced  via 
chemical reaction of ethanol and 
isobutylene.  Most  often  used  as 
oxygenate to gasoline. 
Di-Methyl Ether 
Produced 
by 
methanol for use in CI engines  

hydration 

of 

DME 

MD95 

Other Biofuels 
FAME 

is 

Why 
it 
developed? 

is  being 

Benefits 

Bioethanol  is  a  way  to 
propel  vehicles  on  a 
renewable, 
more 
environmentally-
friendly 
fuel  without 
resorting  to  alternative 
drivetrains and changing 
driver behaviour. 
as 
a 
It 
is 
sustainable 
octane 
enhancer with minimum 
distillation curve impact. 

used 

A sustainable propulsion 
fuel  for  use  in  engines 
using 
inherently 
high  efficiency  diesel 
cycle.  

the 

used 

as 
a 
It 
is 
(sustainable) 
octane 
enhancer with minimum 
distillation curve impact. 
It  is  currently  cheaper 
than ETBE. 
similar 
DME  has  a 
and 
cetane  number 
therefore 
combustion 
properties than diesel. It 
can  be  derived  from  a 
variety 
sources, 
of 
either 
renewable  or 
fossil,  which  makes  it  a 
versatile  and  possibly 
low carbon fuel. 
See  ED95,  if  produced 
sustainably. 

Can have lower WTW GHG 
emissions  as 
long  as 
sustainably  sourced,  no 
driver 
to 
changes 
behaviour, 
high-octane 
fuel. 

octane 

Sustainable 
enhancer. 
Little 
gasoline properties. 

impact  on  other 

engine 

out 
Lower 
emissions  of  PM  and  NOx 
comparing to diesel . 

Sustainable  or  cheaper 
fossil octane enhancer. 
Little 
gasoline properties. 

impact  on  other 

Similarity  to  diesel.  No 
carbon  to  carbon  bonds 
mean  no  engine  out  PM 
emissions.  

see ED95.  

Can have lower WTW GHG 
long  as 
emissions  as 
sustainably sourced. 

75 

Similar 
methanol. 

to  ED95  but  with 

Fatty Acid Methyl Ester 
from 
Type  of  ester  derived 
transesterification  of  fats  with 
methanol.  Can  be  blended  to 
high  levels  into  diesel  for  use  in 
CI combustion engines. 

FAME,  often  referred  to 
as  biodiesel,  is  a way to 
and 
relatively 
cheaply 
the 
renewable  content  of  a 
diesel fuel . 

easily 
increase 

 
 
Technology  and 
fuels 
FT 

Description 

Fischer-Tropsch synthesis 
Liquid  biofuels  can  be  produced 
from  syngas,  which  can  be 
derived from a variety of biomass 
feedstocks, using FT synthesis. 

HVO 

SPK 

to  esterification 

Hydrotreated Vegetable Oil 
Hydrotreating  is  an  alternative 
to 
process 
produce  diesel  from  biomass. 
HVOs  are  commonly  referred  to 
as renewable diesel. 
Synthetic  Paraffinic  Kerosene  or 
iso-paraffins 
There  are  5  major  fuel  routes 
in  civil 
approved  for 
aviation:  FT-SPK,  HEFA-SPK,  HFS-
SIP,  FT-SPKA/A  and  ATJ-SPK. 
There  are  other  seven  routes 
currently under approval process, 
plus other 15 waiting to enter the 
process.  Sustainability  of  those 
pathways  depends  upon 
the 
feedstock and way of production.  

its  use 

Natural gas, propane and derivatives 
CNG 

Compressed Natural Gas 
Methane  rich  gas  stored  at  high 
pressure,  used  as  fuel  in  internal 
combustion engines. 

LNG 

LPG 

Liquefied Natural Gas. 
Methane 
as 
used 
combustion engines. 

fuel 

in 

rich  cryogenic 

fluid 
internal 

Liquefied Petroleum Gas 
light  gaseous 
A  mixture  of 
hydrocarbons.  LPG  is  stored  as  a 
liquid 
5bar 
pressure  predominantly  for  use 
in SI engines. 

approx. 

under 

is 

is  being 

it 
Why 
developed? 
Biofuels  are  a  relatively 
easily 
cheaply 
and 
increase  the  renewable 
content of a diesel fuel. 

Biofuels  are  a  relatively 
easily 
cheaply 
and 
increase  the  renewable 
content of a diesel fuel. 

Benefits 

long 

Can have lower WTW GHG 
emission 
as 
as 
sustainably  sourced,  no 
changes 
driver 
to 
behaviour,  higher  quality 
conventional 
fuel 
diesel. 
Lower 
emissions 
sustainably sourced. 

GHG 
when 

WTW 

than 

Reduced GHG emissions. 

In the absence of radical 
re-designs  of  aviation 
powertrains, 
aviation 
biofuels  are  considered 
to 
the  primary  way 
carbon 
reduce 
footprint 
the 
industry. 

the 

of 

Favourable 
fuel  duty 
relative  to  gasoline  & 
tailpipe 
diesel.  Lower 
CO2  emissions  due  to 
higher H/C ratio.  

Can be used in dual-fuel 
operation  with  heavy 
engines, 
duty  diesel 
such as ships, trains and 
large trucks. 
Can  replace  gasoline  in 
combustion 
internal 
engines  with 
retro-fit 
technology. 

No 

slip 

reduce 

slightly 

GHG 
if 
can  be 
PM 

Can 
emissions 
methane 
avoided. 
emissions.  
Could  be  used  as  interim 
fuel to bio-methane. 
See  CNG.  Higher  energy 
density  by  volume  than 
CNG. 

Lower 
pollutant 
emissions,  relatively  small 
GHG  emissions  benefits, 
lower  cost  to  drivers  if 
taxes kept low. 

76 

 
 
Technology  and 
fuels 
GTL 

Description 

Gas To Liquids 
A process by which natural gas is 
converted  in  liquid  fuels  such  as 
gasoline,  diesel  or  jet  fuel.  Most 
commonly done through Fischer-
Tropsch (FT) synthesis. 

is 

is  being 

it 
Why 
developed? 
GTL  liquids  can  be  used 
as  direct  replacement 
for conventional fuels. 

Benefits 

Possible  way  of  making 
use  of  stranded  gas  and 
that  would 
methane 
otherwise be flared. 

Electricity 
BEV 

PHEV 

Fuel Cells 
Hydrogen  Fuel 
Cell vehicles 

Battery Electric Vehicles. 
Vehicles  propelled  by  electric 
motors  using  electrical  energy 
stored in on-board batteries. 

BEVs  are  an  alternative 
to  conventional  internal 
combustion vehicles. 

Plug-in Hybrid Electric Vehicles 
Vehicles  with  two  propulsion 
systems on-board (electric motor 
and  internal  combustion  engine) 
that  can  work  simultaneously  or 
in isolation. 

PHEVs  are  transitional 
between 
conventional 
and electric vehicles or a 
vehicles 
for 
solution 
with 
full 
to 
limits 
electrification. 

Low 
and 

No  pollutant  or  CO2 
emissions  on  a  Tank-To-
Wheels  basis,  and  high 
GHG 
efficiency. 
emission 
OPEX 
depend  on  the  electricity 
source. 
Working  in  electric  mode 
provides 
same 
benefits as EVs, but PHEVs 
offer flexibility and reduce 
factors  such  as 
range 
anxiety. 

the 

cells 

electric 
produce 
Fuel 
current 
chemical 
through  a 
reaction,  which  propels  a vehicle 
using  electric  motors.  Hydrogen 
is  the  most  common  fuel, stored 
on  board  in  pressurised  tanks. 
Other 
technology  using 
gasoline, natural gas or alcohol is 
also  being  developed,  but  less 
common. 

FC 

Fuel  cell  vehicles  emit  no 
GHGs and pollutants Tank-
to-Wheel.  Hydrogen  as  a 
fuel can be generated in a 
variety  of  ways,  which 
include renewable routes. 

to 

Second  most  common 
alternative  powertrain 
the 
solution 
internal 
conventional 
combustion 
engine, 
after  EVs.  They  could 
have  a  higher  range 
than EVs as well as allow 
quicker  recharge  times 
depending  on  on-board 
storage  and  refuelling 
infrastructure. They also 
have 
similar 
a 
infrastructure  model  to 
conventional  oil 
the 
industry. 

Diesel 
CI 

Dual-Fuel 

Compression Ignition. 
fuel  by  high 
Combustion  of 
compression  of  the  air  inside  a 
cylinder. 
Co-combustion  of  diesel  with 
another  fuel.  A  small  proportion 
of  Diesel 
is 
(pilot 
required to ignite the second fuel 

injection) 

High  efficiency  and  cost-
effective technology. 

Allows using other types 
of  fuel  in  diesel  cycle 
engines. 

High  diesel  like  efficiency. 
Same  benefits  as  offered 
by  the  alternative 
fuel 
used (e.g. LPG, CNG, LNG). 

77 

 
 
 
Technology  and 
fuels 
HPDI 

HCCI 

MGO 

HFO 

Gasoline 
SI 

CAI 

Aftertreatment 
TWC 

EGR 

Description 

injects  both 

High Pressure Direct Injection. 
A 
technology  developed  by 
Westport  specifically  for  natural 
gas,  which 
the 
alternative  fuels  and  the  small 
amount  of  diesel  as  pilot  fuel 
directly into the cylinder. 
Homogeneous 
Compression Ignition. 
A  type  of  internal  combustion 
process  in which  fuel  and  air  are 
compressed to the point of auto-
ignition. 
Marine Gas Oil 
Oil  made  from  distillate  only, 
roughly  equivalent  to  No.  2  fuel 
oil. 

Charge 

Heavy Fuel Oil. 
Pure  or  nearly  pure  residual  oil, 
roughly  equivalent  to  No.  6  fuel 
oil. 

in 
is 

Spark Ignition. 
Internal  combustion  engine 
which  combustion  process 
initiated by a spark plug. 
Controlled Auto Ignition. 
Essentially  a  HCCI  for  gasoline, 
where 
ignition 
thermal 
conditions  are  achieved  at  the 
end of compression. 

a 
(oxidation 

Three way catalyst. 
An  emissions  control  device 
redox 
through 
catalysing 
reaction 
and 
reduction). 
Exhaust Gas Recirculation 
Engine  technology  that  takes 
some  exhaust  gas  and  feeds  this 
back  into  the  engine.  This  has  a 
dilution  effect  that  lowers  the 
combustion 
temperature 
ensuring lower levels of NOx. 

is 

is  being 

it 
Why 
developed? 
The 
technology 
maximises  the  use  of 
fuel  while 
alternative 
maintaining 
equal 
horsepower  and  torque 
characteristics. 

Benefits 

Overall  benefits  the  same 
as  with  the  use  of  natural 
gas. 

High  efficiency  at 
low 
engine  out  emission 
levels. 

Achieves very low levels of 
NOx  emissions  without  a 
catalytic converter. 

Much 
emissions than HFO. 

less 

pollutant 

With  restrictions  put  on 
pollutant  emissions  for 
inland  maritime, 
low 
emission  fuels  allow  to 
avoid  expensive  retrofit 
costs. 

The  cheapest 
fuel 
marine applications. 

for 

see HCCI 

See HCCI 

Increasingly 
stringent 
pollution  limits  require 
to 
manufacturers 
research 
novel 
into 
catalytic solutions. 

Decreased  amounts  of  HC 
to 
and  CO 
carbon 
and 
water). 

(reduced 

dioxide 

Decreased amount of NOx 
pollutant emissions. 

78 

 
 
 
 
 
Technology  and 
fuels 
DOC 

SCR 

DPF / GPF 

LNT 

Description 

is 

it 
Why 
developed? 

is  being 

Benefits 

Diesel Oxidation Catalyst 
A  device  utilising  a  chemical 
process to break down pollutants 
into less harmful components. 
Selective Catalytic Reduction 
An  advanced  active  emissions 
control  technology  that  injects 
urea 
into  the  exhaust  of  the 
diesel engine. 
Diesel  /  Gasoline  Particulate 
Filter.  A 
traps 
filter 
particulate  matter.  When  full  it 
needs 
through 
regeneration 
to 
retarding 
generate  enough  heat  to  oxidise 
the PM.  
Lean NOx Trap 
Stores the NOx temporarily when 
in the correct temperature range, 
but  requires  regeneration.  This 
run 
the  engine 
requires 
stoichiometric  or  rich  to  allow 
the NOx to be converted to N2. 

the  combustion 

that 

to 

Decreased  amount  of  HC 
and 
pollutant 
emissions. 

CO 

Breaks down NOx into less 
harmful N2. 

Decreased  amount  of  PM 
emissions. 

Breaks down NOx into less 
harmful N2. 

7.3  Impact of alternative fuel deployment and development  
In this section  alternative fuel  and powertrain  combinations are  scored on their potential to meet 
key EC objectives by 2050 using the following scoring criteria.  

Criteria 

Definition 

Low 

Medium 

High 

GHG 

TTW 
emissions  

TTW noxious 
emissions 

improvement 
Engine  efficiency 
potential  to  2030  relative  to  the 
incumbent  technology  (e.g.  40% 
now  to  45% 
is  5% 
improvement) 

in  2030 

Contribution 
to  TTW  noxious 
(specifically  NOx  &  PM)  emissions 
reduction  potential 
2030 
to 
incumbent 
to 
compared 
technology  (incl.  after  treatment) 
on a vehicle basis  

Under 5% 

5 to 10% 

Above 10% 

material 

No 
change 

Less  than  an 
order 
of 
magnitude 
improvement 

More  than  and 
order 
of 
magnitude 
improvement 

EU 
competitive
ness 

On  balance,  contribution  to  a 
competitive  advantage  for  the  EU 
industry  

Low potential 

Medium 
potential 

High potential 

79 

 
 
 
 
This  is  repeated  for  each  transport  mode.  The  tables  have  been  compiled  based  on  expert 
knowledge, survey responses, and discussions held at a stakeholder workshop on 24 May 2016 (see 
list of stakeholders consulted in Annex 7.4).  

80 

 
 
 
Powertrai
n 
technology 
SI 

CI 

FC 

CI 

SI 

CI 

7.3.1  LDV 

Fuel 

TTW GHG emissions 

TTW noxious emissions 

EU competitiveness 

Alcohols, ethers 
& esters 

Slight  efficiency  improvements  of  up  to  5% 
through  higher  RON.  Fuels  to 
include  are 
ethanol,  methanol  and  other  alcohol  mixtures, 
but 
ETBE  
MTBE 
This could allow further downsizing / speeding / 
enleanment. 

also 

and 

High  Alcohol  blends  significantly  reduce  engine 
out 
NOx.  
Note:  the  emission  of  non-regulated  aldehyde 
emission could increase.  

and 

PM 

Optimised  engine  and  fuel  technology  would 
increase 
industry 
EU 
competitiveness..  

automotive 

Alcohols, ethers 
& esters 

Engine  efficiency  similar  to  current  CI  diesel 
engines. 

Significant 
DME and ED95. FAME less so. 

improvement  demonstrated  from 

Alcohols, ethers 
& esters 

FC  has  typically  a  higher  engine  efficiency 
especially at part load (real world) conditions. 

 Very low emissions from FC systems. 

Optimised  engine  and  fuel  technology  would 
increase 
industry 
EU 
competitiveness  

automotive 

Optimised  engine  and  fuel  technology  would 
industry 
EU 
increase 
competitiveness.  

automotive 

gasoline/napht
ha 

Liquid 
petroleum  gas 
(LPG) & bioLPG 

For use of naphtha rather than diesel. 

Specifically particulates reduction. 

Improvement  from  compression  ratio  increase 
and direct injection. 

Three  way  catalyst  already  very  effective 
Reduction in PM. 

in  direct 

injection  engines  fits  well 

LPG 
in 
European engine designs and bioLPG production 
fits with HVO production. 

Natural  gas  / 
bio-methane 

Efficiency  improvement  relative  to  the  CI  diesel 
engine 
difficult.  
is 
A dual fuel system using a CI combustion process 
would need to utilised here. 

DF  systems  should  significantly  reduce  PM. 
Engine  out  NOx  might  be  reduced  by  finding  a 
better 
trade-off  with  CO2.  Aftertreatment 
systems could be optimised further. 

European  countries  have  developed  very  up  to 
date  technologies  for  natural  gas  vehicles,  for 
which Europe still has a leading role. 

81 

 
 
 
 
 
 
  
 
 
 
Powertrai
n 
technology 
SI 

Fuel 

TTW GHG emissions 

TTW noxious emissions 

EU competitiveness 

Natural  gas  / 
bio-methane 

Higher  efficiency  of  SI  engines  through  the  use 
of  gas  is  possible  in  the  form  of  downsizing  or 
enleanment  New  technologies  such  as  HPDI, 
high  pressure  direct  injection,  downsizing  with 
turbo-charging,  etc.  can  lead  to  higher  energy 
efficiency, and sharp decrease of CO2 emissions: 
even  to  40%  compared  to  the  present  gasoline 
engines is possible in prospect. 

Natural gas engines emit extremely low PM, and 
low  regulated  pollutants,  even  without  the 
complex  treatment  systems  used  with  other 
fuels.  Very  low  or  absent  are  also  other  non-
regulated  noxious  substances, 
in  particular 
unburned  carcinogenic  substances  such  as 
aromatics. 

European  countries  have  developed  very  up  to 
date  technologies  for  natural  gas  vehicles,  for 
which Europe still has a leading role. 

CI 

SPFs 

additional 
Difficult to improve CI engine efficiency. 

tuning 

possible 

Potentially  very  beneficial  for  existing  fleet 
CI engine aftertreatment very effective already. 

Opportunity  for  EU  to  develop  new  innovative 
fuel technology. 

SI 

SPFs 

depends on final product quality (eg RON). 

Depends on final quality (eg aromatics content).  Opportunity 

for  EU  to  develop  new 

fuel 

innovative technology. 

Powertrai
n 
technology 
CI 

SI 

7.3.2  HDV 

Fuel 

TTW GHG emissions 

TTW noxious emissions 

EU competitiveness 

Alcohols, ethers 
& esters 

Engine  efficiency  similar  to  current  CI  diesel 
engines. 

Significant 
DME and ED95. FAME less so. 

improvement  demonstrated  from 

Liquid 
petroleum  gas 
(LPG) & bioLPG 

Improvement  from  compression  ratio  increase 
and direct injection. 

Three  way  catalyst  already  very  effective 
Reduction in PM. 

automotive 

Optimised  engine  and  fuel  technology  would 
increase 
industry 
EU 
competitiveness. 
in 
LPG 
European engine designs and bioLPG production 
fits with HVO production. 

injection  engines  fits  well 

in  direct 

82 

 
 
 
 
 
 
 
 
 
Powertrai
n 
technology 
CI 

Fuel 

TTW GHG emissions 

TTW noxious emissions 

EU competitiveness 

Natural  gas  / 
bio-methane 

Efficiency  improvement  relative  to  the  CI  diesel 
engine is difficult. Lower PM & NOx would allow 
for improved fuel eff. 

DF  systems  do  significantly  reduce  PM.  Engine 
out  NOx  might  therefore  be  reduced  and 
aftertreatment systems optimised. 

European  countries  have  developed  very  up  to 
date  technologies  for  natural  gas  vehicles,  for 
which Europe still has a leading role. 

SI 

Natural  gas  / 
bio-methane 

New  technologies  such  as  HPDI,  high  pressure 
direct  injection,  etc.  can  lead  to  higher  energy 
efficiency, and sharp decrease of CO2 emissions, 
thus increasing the CO2 saving compared to HD 
diesel engines. 

CI 

SPFs 

Difficult to improve CI engine efficiency. 

Natural gas engines emit extremely low PM, and 
low  regulated  pollutants,  even  without  the 
complex  treatment  systems  used  with  other 
fuels.  Very  low  or  absent  are  also  other  non-
regulated  noxious  substances, 
in  particular 
unburned  carcinogenic  substances  such  as 
aromatics. 
Euro  VI  SI  &  CI  engines  already  have  very  low 
TTW noxious emissions.  
SCR+DPF aftertreatment very effective. 

Turbine 

SPFs 

Turbo-engines are not efficient in small scale. 

Other 

SPFs 

Composite  piston-turbo  cycle  allows  for  very 
high pressure ratios. 

Lean operation. 

European  countries  have  developed  very  up  to 
date  technologies  for  natural  gas  vehicles,  for 
which Europe still has a leading role. 

Europe leading fuel production technology. 

Patent priority and proprietary technology. 

Patent priority and proprietary technology. 

Powertrai
n 
technology 
CI 

7.3.3  Rail 

Fuel 

TTW GHG emissions 

TTW noxious emissions 

EU competitiveness 

Biodiesel 

For B20, engine efficiency similar to current fuel.  
For  higher  ratio,  the  performances  of  existing 
locomotive deiesel engine can been affected. 

No change. 

Developing  new  engine  able  to  run  with  more 
than  20%  biodiesel 
increase  EU 
competitiveness. 

could 

83 

 
 
  
 
 
 
 
 
Powertrai
n 
technology 
SI 

Fuel 

LNG 

TTW GHG emissions 

TTW noxious emissions 

EU competitiveness 

Energy  efficiency  is  in  the  same  range  as  the 
diesel engine. 

NOx and PM emissions are by 70% lower. 

Developing  new  locomotive  offers  alternative 
for  the  transport 
decarbonisation  pathway 
sector. 

7.3.4  Waterborne transport 

Fuel 

TTW GHG emissions 

TTW noxious emissions 

EU competitiveness 

Powertrai
n 
technology 
CI 

Biodiesel 

CI, DF 

Methanol 

Pressurizing  the  cylinder  helps  to  reduce  the 
emissions  (NOx)  and  optimise  the  combustion 
process.  
Electronic  control  injection  will  improve  the 
degree of fuel atomisation. 

Methanol  has  high  octane  number  -  very 
efficient engine performance. 
Tests run by different engine designers indicated 
that  the  fuel  efficiency  is  the  same  or  better 
when running on methanol. 
Advanced  injection  systems  potentially  provide 
further improvements in terms of efficiency. 

No Significant change. 

Optimised  engine  technology  and  fuel  handling 
techniques would increase EU competitiveness. 

Global reduction of noxious emissions proved by 
Motorways of the Seas project. 
NOx  emissions  during  combustion  are  reduced 
by  approximately  60  %  when  running  on 
methanol 
Significant 
reduction in SOx. 
Advanced  injection  systems  potentially  provide 
further 
improvements  in  terms  of  pollutant 
emissions. 

compared 

to  HFO. 

World’s  first  methanol  powered  ferry  was 
launched through an EU project. 

84 

 
 
 
 
 
 
Powertrai
n 
technology 
SI  

Fuel 

TTW GHG emissions 

TTW noxious emissions 

EU competitiveness 

Natural  gas  / 
bio-methane 

SI 
lean  burn  gas  engine  has  high  energy 
efficiency only at high loads. For the entire load 
range,  energy  efficiency  can  be  in  the  same 
range  as  the  diesel  engine,  but  the  emissions 
(NOx) are kept low. 

Using LNG gaseous emissions meet IMO Tier III. 
SOx emission is  eliminated. PM is close to zero. 
NOx  is  reduced  by  80-90%  due  to  low  flame 
temperatures during lean burning. 
SI marine engines emit ultrafine PM. 

It Is sensitive to gas quality and not suitable for 
retrofit existing engine. 

European  manufacturers  are  world  leaders  in 
developing robust engines for LNG-fuelled ships. 
Bio-methane can be produce locally, offering the 
perspective 
energetic 
reducing 
dependency. 

EU 

of 

CI, DF 

Natural  gas  / 
bio-methane 

DF  has  diffusion  burning  which  ensure  better 
capability of burning gases. MAN states that its  
dual-fuel  LNG  engine  achieves  50  %  peak 
thermal  efficiency,  compared  to  diesel  engines, 
with lower fuel consumption. 
Conversion  of  existing  engines  with  rebuilding 
work. 
Sensitive to gas quality. 
Advanced  injection  systems  potentially  provide 
further improvements in terms of efficiency. 

DF  systems  have  very  good  influence  on  PM 
reduction. Aftertreatment (EGR, SCR) of exhaust 
gases is needed to comply with IMO Tier III-NOx 
emission limits. 
Advanced  injection  systems  potentially  provide 
further 
improvements  in  terms  of  pollutant 
emissions. 

European  manufacturers  are  world  leaders  in 
developing robust engines for LNG-fuelled ships. 
Bio-methane can be produce locally, offering the 
perspective 
energetic 
reducing 
dependency. 

EU 

of 

Powertrai
n 
technology 
Turbofan 

7.3.5  Aviation 

Fuel 

TTW GHG emissions 

TTW noxious emissions 

EU competitiveness 

SPK (FT,HEFA) 

SPK  is  less  energy  dense  than  conventional  jet, 
but it has higher specific energy 
Small gain.  

Lower nvPM  as much as related with a relatively 
lower aromatics and S content.  

As  there  are  CO2  global  reduction  targets  for 
aviation,  having  available  and  affordable  ways 
for 
sector 
be 
competitiveness. 

aviation  will 

key 

for 

85 

 
 
 
 
 
Fuel 

TTW GHG emissions 

TTW noxious emissions 

EU competitiveness 

Powertrai
n 
technology 
Turbofan 

SIP 

Higher  energy  content  per  volume,  lower  per 
weight. Small gain.  

Lower nvPM  as much as related with a relatively 
lower aromatics and S content. 

Turbofan 

ATJ 

Higher  energy  content  per  volume,  lower  per 
weight. Small gain.  

Lower nvPM  as much as related with a relatively 
lower aromatics and S content. 

Turbofan  HEFA+ 

Higher  energy  content  per  volume,  lower  per 
weight. Small gain.  

Lower nvPM  as much as related with a relatively 
lower aromatics content. 

Turbine 

LNG 

Lower PM and NOx.  

for 

key 

aviation  will 

As  there  are  CO2  global  reduction  targets  for 
aviation,  having  available  and  affordable  ways 
for 
sector 
be 
competitiveness. 
As  there  are  CO2  global  reduction  targets  for 
aviation,  having  available  and  affordable  ways 
for 
sector 
be 
competitiveness. 
No 
but 
technology 
significant 
decarbonisation  is  a  key  for  competitiveness  in 
aviation. 

aviation  will 

change, 

key 

for 

86 

 
 
 
 
 
7.4  Stakeholders consulted 

  ACI 
  Airbus 
  Bauhaus 
  Becker Marine Systems 
  Biochemtex 
  British Airways 
  CLEPA 
  CONCAWE 
  Daimler 
  DNV/GL 
  ENI 
  ERTRAC 
  FIAT 
  Honeywell 
 
ICCT 
 
IDIADA 
 
Italian Ministry of Transport (CPT/IMO) 
 
JRC  
 
Lufthansa 
  MIT 
  Renault 
  Repsol 
  Rolls-Royce 
  SAFRAN 
  Scania 
  SENASA (Services and Studies for air navigation and aeronautical safety) 
  T&E 
  Toyota Europe 
  UIC 
  Volkswagen 

 
 
 
 
 
 
 
 
 
 
 
 
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Studies and reports