Future Transport Fuels and Decarbonisation

Barcelona, September 18, 2018.- The sources of energy / combustion that drives the truck engine in the transport of goods are the most sensitive variable. Diesel is the king fuel, but there are other sources that can be interesting for very specific routes and specific merchandise. Below we summarize a report of the European Union on all fuels and the tendency to avoid the most polluting.

Transport fuel supply today, in particular to the road sector, is dominated by oil  which has proven reserves that are expected to last around 40 years. The combustion of mineral oil derived fuels gives rise to CO2 emissions and, despite the fact the fuel efficiency of new vehicles has been improving, so that these emit significantly less CO2, total CO2 emissions from transport have increased by 24% from 1990 to 2008, representing 19.5% of total European Union (EU) greenhouse gas emissions.

The EU objective is an overall reduction of CO2 emissions of 80-95% by the year 2050, with respect to the 1990 level [3]. Decarbonisation of transport and the substitution of oil as transport fuel therefore have both the same time horizon of 2050. Improvement of transport efficiency and management of transport volumes are necessary to support the reduction of CO2 emissions while fossil fuels still dominate, and to enable finite renewable resources to meet the full energy demand from transport in the long term.  Alternative fuel options for substituting oil as energy source for propulsion in transport are:

  • Electricity/hydrogen, and biofuels (liquids) as the main options
  • Synthetic fuels as a technology bridge from fossil to biomass based fuels
  • Methane (natural gas and biomethane) as complementary fuels
  • LPG as supplement

Electricity and hydrogen are universal energy carriers and can be produced from all primary energy sources. Both pathways can in principle be made CO2 free; the CO2 intensity depends on the energy mix for electricity and hydrogen production. Propulsion uses electric motors. The energy can be supplied via three main pathways:

Battery-electric, with electricity from the grid stored on board vehicles in batteries. Power transfer between the grid and vehicles requires new infrastructure and power management. Application is limited to short-range road transport and rail. The development of cost- competitive high energy density batteries and the build-up of charging infrastructure are of the highest priority.

Fuel cells powered by hydrogen, used for on-board electricity production. Hydrogen production, distribution and storage require new infrastructure. Application is unlikely for aviation and long-distance road transport. The development of cost-competitive fuel cells, on- board hydrogen storage, and strategic refuelling infrastructure is of the highest priority.

Overhead Line / Third Rail for tram, metro, trains, and trolley-buses, with electricity taken directly from the grid without the need of intermediate storage.

Biofuels could technically substitute oil in all transport modes, with existing power train technologies and existing re-fuelling infrastructures. Use of biomass resources can also decarbonise synthetic fuels, methane and LPG. First generation biofuels are based on traditional crops, animal fats, used cooking oils. They include FAME biodiesel, bioethanol, and biomethane. Advanced and second generation biofuels are produced from ligno-cellulosic feedstock and wastes. They include bioethanol, HVO, higher alcohols, DME, BTL and biomethane.

The production of biofuels from both food and energy crops is limited by the availability of land, water, energy and co-product yields, and sustainability considerations, such as the life-time accountancy of CO2 emissions. Second generation biofuels from wastes and residues are also limited by the availability of these materials.

The development of feedstock potential and of optimised production processes is of the highest priority. A supportive policy framework at the EU level and harmonised standards for biofuels across the EU are key elements for the future uptake of sustainable biofuels.

Synthetic fuels, substituting diesel and jet fuel, can be produced from different feedstock, converting biomass to liquid (BTL), coal to liquid (CTL) or gas to liquid (GTL). Hydrotreated vegetable oils (HVO), of a similar paraffinic nature, can be produced by hydrotreating plant oils and animal fats. Synthetic fuels can be distributed, stored and used with existing infrastructure and existing internal combustion engines.

They offer a cost-competitive option to replace oil- based fuels, with the perspective of further improved system performance with engines specifically adapted to synthetic fuels. The development of industrial scale plants for the production of cost-competitive synthetic fuels derived from biomass is of the highest priority, while efforts should be continued to improve the CO2balance of GTL and particularly CTL. DME (Di-Methyl-Ether) is another synthetic fuel produced from fossil or biomass resources via gasification (synthesis gas), requiring moderate engine modifications.

Methane can be sourced from fossil natural gas or from biomass and wastes as biomethane. Biomethane should preferentially be fed into the general gas grid. Methane powered vehicles should then be fed from a single grid. Additional refuelling infrastructure has to be built up to ensure widespread supply. Propulsion uses internal combustion engines similar to those for liquid hydrocarbon fuels. Methane in compressed gaseous form (CNG) is an unlikely option where high energy density is required. Liquefied methane gas (LNG) could be a possible option in these cases. Harmonised standards for biomethane injection into the gas grid and the build-up of EU- wide refuelling infrastructure are of the highest priority.

LPG (Liquefied Petroleum Gas) is a by-product of the hydrocarbon fuel chain, currently resulting from oil and natural gas, in future possibly also from biomass. LPG is currently the most widely used alternative fuel in Europe, accounting for 3% of the fuel for cars and powering 5 million cars. The core infrastructure is established, with over 27,000 public filling stations.

Single-fuel solutions covering all transport modes would be technically possible with liquid biofuels and synthetic fuels. But feedstock availability and sustainability considerations constrain their supply potential. Thus the expected future energy demand in transport can most likely not be met by one single fuel. Fuel demand and greenhouse gas challenges will require the use of a great variety of primary energies. There is rather widespread agreement that all sustainable fuels will be needed to resolve the expected supply-demand tensions.

The main alternative fuels should be available EU-wide with harmonised standards, to ensure EU-wide free circulation of all vehicles. Incentives for the main alternative fuels and the corresponding vehicles should be harmonised EU-wide to prevent market distortions and to ensure economies of scale supporting rapid and broad market introduction of alternative fuels.

The main alternative fuels considered should be produced from low-carbon, and finally from carbon-free sources. Substitution of oil in transport by these main alternative fuels leads then inherently to a decarbonisation of transport if the energy system is decarbonised. Decarbonisation of transport and decarbonisation of energy should be considered as two complementary strategic lines, closely related, but decoupled and requiring different technical approaches, to be developed in a consistent manner.

The different transport modes require different options of alternative fuels:

  • Road transport could be powered by electricity for short distances, hydrogen and methane

up to medium distance, and biofuels/synthetic fuels, LNG and LPG up to long distance.

  • Railways should be electrified wherever feasible, otherwise use biofuels.
  • Aviation should be supplied from biomass derived kerosene.
  • Waterborne transport could be supplied by biofuels (all vessels), hydrogen (inland waterways and small boats), LPG (short sea shipping), LNG and nuclear (maritime).

Transport has been the sector most resilient to efforts to reduce CO2 emissions due to its strong dependence on fossil energy sources and its steady growth, offsetting the considerable vehicle efficiency gains made. Energy efficiency, transport efficiency, and effective transport demand management, can substantially contribute to reduce emissions. But the ultimate solution to near full decarbonisation of transport is the substitution of fossil sources by CO2-neutral alternative fuels for transport.

Oil, the main energy source for transport overall, supplying nearly 100% of road transport fuels, is currently expected to reach depletion on the 2050 perspective. Substitution of oil therefore needs to start as soon as possible and increase rapidly to compensate for declining oil production, expected to reach a peak within this decade. Climate protection and security of energy supply therefore both lead to the requirement of building up an oil-free and largely CO2-free energy supply to transport on the time horizon of 2050.

Increased energy efficiency is not an alternative to oil substitution but a bridge to alternative fuels. More efficient use of energy in transport stretches the potential for supply from finite oil reserves, contributes to curbing greenhouse gas emissions from the combustion of fossils, and facilitates full substitution by alternative fuels, which will be production limited rather than reserve limited, as fossil resources.

Therefore, a consistent long-term strategy should aim at fully meeting the energy demand of the transport sector from sustainable and secure largely CO2-neutral sources by 2050.

Decarbonising transport is a core theme of the EU 2020 strategy [4] and of the common transport policy. The long-term perspective for transport in Europe has been laid out in the Commission Communication on the Future of Transport of 2009 [5]. The long-term objective of the European Union on CO2 emissions is an overall reduction of 80-95% by 2050 [3].

The next 10 years are crucial for this 2050 vision. The upcoming White Paper on the European transport policy for the next decade should outline a transport action programme until 2020. It should define the overall framework for EU action over the next ten years in the fields of transport infrastructure, internal market legislation, technology for traffic management and decarbonisation of transport through clean fuels and vehicles.

Strategic initiatives that the European Commission is considering in this context should further develop the technology part. The initiative on Clean Transport Systems, foreseen for the end of 2011, should present a consistent long-term alternative fuel strategy and possible measures to take in the short and medium term. The Strategic Transport Technology Plan, foreseen for mid 2011, should set the priorities for research and technological development of key transport technologies, with an approach similar to the Strategic Energy Technology (SET) Plan launched for the energy sector [6].

The Commission is also reviewing the TEN-T Guidelines. The TEN-T Guidelines are the general reference framework for the implementation of the European transport network and for identifying projects of common interest. They focus on roads, railways, inland waterways, airports, seaports, inland ports and traffic management systems, serving the entire EU territory. The possible future integration of new infrastructure required for alternative fuels in all transport modes has been considered by the “Expert Group on Intelligent Transport Systems and New Technologies within the framework of the TEN-T” [7].

In this context of revising existing policies and launching new strategic initiatives for more sustainable transport in the EU, the Commission established in March 2010 a stakeholder Expert Group on Future Transport Fuels (members in Annex 1), with the objective of providing advice to the Commission on the development of political strategies and specific actions aiming towards the substitution of fossil oil as transport fuel in the long term, and decarbonising transport, while allowing for economic growth.

The Expert Group followed up on the work of the previous Contact Group on Alternative Fuels, which published a comprehensive report in 2003 [8].

The Expert Group on Future Transport Fuels, according to its mandate, should consider the mix of future transport fuels to have the potential for:

  • Full supply of the transport energy demand by 2050
  • Low-carbon energy supply to transport by 2050
  • Sustainable and secure energy supply to transport in the longer term, beyond 2050.

Alternative fuels are the ultimate solution to decarbonise transport, by gradually substituting the fossil energy sources, which are responsible for the CO2 emissions of transport. Other measures, such as transport efficiency improvements and transport volume management, play an important supporting role.

Energy carriers as transport fuels should be given particular attention, as they can be produced from a wide range of primary energy sources. They allow transport to take full advantage of the expected gradual decarbonisation of the energy system, resulting from a steady increase in the share of non-CO2emitting energy sources. Energy carriers as fuels also ensure the security of energy supply to transport by providing diversification of energy sources and suppliers, whilst allowing for a smooth transition from fossil to renewable energy sources.

Compatibility of new fuels with current vehicle technology and energy infrastructure, or alternatively the need for disruptive system changes should be taken into account as important determining factors influencing the introduction of alternative fuels. The Expert Group on Future Transport Fuels was allocated the following main tasks:

  • Assess market potential, technological issues, economic viability, industrial implications, social and demographic aspects, environmental impacts, and safety of the different fuels considered as part of a long term oil substitution for transport fuels
  • Consider factors that could affect long term viability of alternatives, including security of supply, availability of feedstock, resources required for the fuel chain
  • Design scenarios towards full substitution of fossil energy sources for transport fuels
  • Devise a development and field testing programme and identify needs for public support
  • Recommend actions and policy measures towards full substitution of oil as transport fuel.

Sources of information consulted: European Expert Group, EU, ACEA. Wall2born.com (Photo).

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