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| There are various substitutes for diesel fuel ranging from biodiesel (e.g. oil esters from rape seed) to "synthetic" fuels. The following evaluation refers to rape oil methyl-ester (RME). Biodiesel can be used on all diesel engines with slight or no modification. Blending with conventional diesel is possible. |
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| Technology field: Optimisation of traction technologies |
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General information | ||||
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Description | ||
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Diesel substitutes There are several diesel substitutes available: Liquid bio-fuels:
"Synthetic" fuels (not treated here):
Rape oil methyl-ester (RME) The following evaluation refers to biofuels, particularly to rape oil methyl-ester (RME). RME is esterified rape-oil. The esterification process uses the catalytic impact of methanol and heat for producing RME. Fields of application: All fields of application of diesel fuel. Manufacturer: There are numerous RME suppliers including
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General criteria | ||||
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Status of development: test series | ||
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Biofuels were tested by German DB AG (tests with RME in DMUs), Czech CD and Hungarian MAV and possibly others. | ||
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Time horizon for broad application: 5 - 10 years | ||
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Due to high barriers to be overcome and problems to be resolved, broad application will hardly be realised in the next five years. Broad application is however generally doubtful due to economic and environmental drawbacks. | ||
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Expected technological development: basically exploited | ||
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cf. Technological potential outside railways | ||
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Motivation: | |||
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The main motivation for the use of biodiesel lies in fuel availability, regenerativity (and consequent CO2 reduction) and lower toxic emissions. Some railways may consider biofuels if fuel cells fail. | ||
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Benefits (other than environmental): small | ||
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Compared to natural gas In contrast to natural gas, biodiesel can be used on the same motors as conventional diesel. Land use Planting rape may be a reasonable alternative to make use of fallow land. |
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Barriers: high | ||
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Costs The production of biodiesel is very expensive and can currently only subsist with subventions. Infrastructure Biodiesel would require a parallel supply infrastructure (at least during parallel use with conventional diesel). Wear Due to its chemical properties, RME increases motor wear (especially on gaskets etc.). In many cases RME resistant motor components are required. Lubricant dilution Combustion temperature has to be carefully controlled, since low temperature may lead to the dilution of oil lubricant. Smell The exhaust of biodiesel has an unpleasant smell (similar to french fries!). Storage Being a natural product, biodiesel can be affected and destroyed by bacteria infestation. This may be a problem for fuel storage. Legislation CD (Czech Railways) carried out tests, but legislation prevents introduction into fleet. Environmental balance Cultivation of rape implies the use of toxic substances like pesticides and extensive area consumption. |
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Success factors: | |||
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The production of rape depends to a certain extent on EU regulations (including limits for oil-seed cultivation). The European Commission plans a program for funding alternative fuels including biodiesel. | ||
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Applicability for railway segments: medium | ||
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Type of traction: diesel | |||
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Type of transportation: passenger - main lines, passenger - regional lines, passenger - suburban lines, freight | |||
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Virtually all diesel vehicles can run on biodiesel. | ||
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Grade of diffusion into railway markets: | |||
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Diffusion into relevant segment of fleet: < 5% | ||
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Share of newly purchased stock: (no data) | ||
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RME or vegetable oil do not play any role in European rail operation yet. | ||
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Market potential (railways): low | ||
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In principle, railway diesel fleets could operate on biodiesel but limitations make a wide-spread use unlikely. | ||
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Example: | |||
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No in-service use at present. | ||
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Environmental criteria | ||||
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Impacts on energy efficiency: | ||
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Energy efficiency potential for single vehicle: not applicable | ||
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Energy efficiency potential throughout fleet: not applicable | ||
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Energy content of biodiesel is about 10% lower than for ordinary diesel. Energy efficiency is difficult to assess in the case of alternative fuels since there is no reasonable point of reference. An energy balance of biodiesel has to take into account the energy input needed to produce the rape and process it to obtain RME. This is best be done by a CO2 balance. CO2 balance A CO2 comparison between RME and fossil diesel has to take into account CO2 emissions from the whole energy chain (i.e. caused by the production and processing and transport of the respective fuel). A very thorough environmental balance by the German IFEU institute revealed a specific CO2 advantage of RME over diesel between 30 and 80 % per kilogram of fuel (depending on the energetic use of the by-products). However, the total possible savings in CO2 are seen as very modest due to the limited agricultural capacity to grow rape. |
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Other environmental impacts: ambivalent | ||
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Toxic emissions Toxic emissions from the combustion of RME as compared to diesel:
Pollution effects of rape cultivation The cultivation of rape causes the emission of N2O (laughing-gas) which is also a greenhouse gas. Furthermore the large extent of land use and the extensive utilization of fertilizers and pesticides are negative from an environmental point of view. Eco-balance A thorough study by the German IFEU institute concluded that RME “holds no distinct advantages for the environment” (Umweltbundesamt 2001). |
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Economic criteria | ||||
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Vehicle - fix costs: low | ||
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There are some minor costs for modifying diesel engines (replacing non-RME-resistant components). The experiences from the automotive sector (bus fleet of German KWH – Kreiswerke Heinsberg) show refitting costs that are appreciably lower than for a refit necessary for natural gas use: about 3.500 EURO compared to 35.000 EURO per vehicle. These figures may not be transferable to railways. | ||
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Vehicle - running costs: not applicable | ||
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According to EU Commssion, price for biodiesel is currently about 0.30 EURO higher than diesel price (also depends on mineral oil taxation). German DB AG calculates about 0,50 to 0,60 EURO/litre for RME, 20-25% more than for diesel. | ||
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Infrastructure - fix costs: medium | ||
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There will be costs for RME supply infrastructure (additional tanks in service stations etc.). Since a complete transition of the diesel fleet to RME is extremely doubtful, this infrastructure would be additional. | ||
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Infrastructure - running costs: increased | ||
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Parallel (RME diesel) infrastructure involving fuel supply and storage etc. would cause additional running costs. | ||
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Scale effects: low | ||
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Limitations for a wide-spread introduction will impede major scale effects. | ||
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Amortisation: not applicable | ||
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No amortisation due to increased running costs! | ||
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Application outside railway sector | ||||
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Status of development outside railway sector: in use | ||
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Biodiesel is already used in the automotive and truck sector. An example is Kreiswerke Heinsberg KWH, Germany, which migrated the whole fleet of busses to biodiesel by 1998. The production of rape-oil-methylester (RME-biodiesel) doesn’t hit upon substantial obstacles. | ||
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Time horizon for broad application outside railway sector: in 5 - 10 years | ||
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Broad application is doubtful due to economic and environmental drawbacks. Furthermore, agricultural capacity for rape production is a limiting factor. A rapid diffusion into the diesel fleet will be impeded by limited agricultural areas in Europe. Most rape is planted on fallow land. In the EU there is a limit for the production of oil-seed (Blair-House-Agreement) motivated by trade policies. Current capacities allow for a biodiesel production of 1,4 million tons. The potential may be considerably greater in Eastern Europe, especially Poland, Hungary, the Czech Republic and Bulgaria, due to big stretches of fallow land. In Germany, the substitution of conventional diesel by biodiesel is much less than 1% (2000/2001). Even if all the areas permitted for rape cultivation were used, the degree of substitution would not exceed 0.5 %. | ||
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Expected technological development outside railway sector: basically exploited | ||
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There is some potential in the production of RME:
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Market potential outside railway sector: small | ||
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A wide-spread introduction in the automotive sector is doubtful due to limitations set out in Time horizon for broad application. | ||
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Overall rating | ||||
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Overall potential: not promising | ||
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Time horizon: (no data) | ||
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At first sight, rape oil methyl-ester (being a regenerative fuel) promises substantial environmental advantages over diesel fuel from fossile sources. However, a thorough environmental assessment shows that the effects of biodiesel are ambivalent. In view of additional economic problems such as high price and lack of production capacity for generalised use, the potential of biodiesel for railway applications is very doubtful. | ||
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| References / Links: Bünder 2001; DB AG, Zentralbereich 1996; Hörl et al. 2001; IFEU 2000; Institute of Transport... 2001; Nolte et al. 1998; Umweltbundesamt 2000; UNDP 1997; Pfretzschner (1997) |
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| Attachments: |
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| Related projects: Energy chains of alternative fuels |
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| Contact persons: |
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 date created: 2002-10-09 |
| © UIC - International Union of Railways 2003 |
