- Why Biofuels?
- What are biofuels?
- Which biofuels are available (and what are their associated manufacturing process)?
- What are 1st-generation and 2nd-generation biofuels?
- Where do vehicles run on biofuels?
- What is the current policy within the European Union?
- What else would I need to consider when changing to biofuels?
- Further Information
1. Why biofuels?
In the EU, transport is responsible for an estimated 21% of all greenhouse gas emissions, which contribute to global warming, and this percentage is rising. In order to meet sustainability goals, in particular the reduction of greenhouse gas emissions agreed under the Kyoto Protocol, it is therefore essential to find ways of reducing emissions from transport.
With this in mind the EU has set out policy objectives, namely an efficiency policy influencing the use of vehicles and a policy for climate-neutral transport fuels. Biofuels are fuels that are potentially climate-neutral, i.e. plants and trees are used as an energy source. The CO2 naturally absorbed by plants and trees is released when these are used as fuel. This results in no extra CO2 emissions, so we call this a climate-neutral fuel. However, energy is required to grow feedstock and to produce biofuels, which does have an effect on the CO2 emission levels. The current generation of biofuels achieves a 30-50% reduction in CO2 emissions, when compared with fossil fuels. In the future, biofuels will be developed in such a way that they can potentially achieve a reduction of around 90% or even higher. By promoting the use of biofuels the EU hopes to contribute to the reduction of greenhouse gas emissions in the transport sector.
In addition to reducing CO2 emissions, the security of our energy supply and support for the agricultural sector are also important considerations for this EU directive.
2. What are biofuels?
Biofuels are liquid or gaseous fuels that are manufactured from biomass, such as agricultural crops and the biodegradable parts of waste. Biofuels can replace fossil fuels, such as petrol or diesel, either totally or partially in a blend. The concept of using biofuels in combustion engines dates back to over 100 years ago. At the end of the 19th century the inventor of the diesel engine, Rudolf Diesel, created engines running on peanut oil, while at the beginning of the 20th century, Henry Ford observed that bioethanol would be the best fuel for his Model T Fords.
There are many types of biofuels (see also point 3). Only pure plant oil (PPO), biodiesel, bioethanol and biogas are currently commercially available, but massive research is currently being conducted into advanced production methods, such as a more efficient way of manufacturing bioethanol and Fischer Tropsch diesel. Whether or not a car engine needs to be modified to run on biofuel, depends on the type of biofuel used. For example, biodiesel is a diesel fuel which can be made from plant oil. The viscosity of biodiesel is higher than conventional diesel and the fuel does not ignite as easily in the engine. It is often possible to blend 20% biodiesel with the fossil-based diesel without engine modifications of any kind, however higher blending percentages require the engine to be modified.
Ethanol is another example of a biofuel, generally produced from sugar cane or grain. Ethanol is currently the most popular biofuel around the world. In Brazil, ethanol is manufactured from sugar cane and is available at almost all filling stations, either in pure form or blended with conventional petrol. Ethanol is an alcohol that can be blended (up to 5%) with petrol, without any engine modifications required. Higher percentages, e.g. E85 (85% ethanol) require vehicle engines to be modified. Various car manufacturers, are launching special models of their cars on the EU market. These are the so-called flexi-fuel cars that can run on both E85 and conventional petrol, or a mixture thereof. Current EU regulations for fuel specifications do not (as yet) allow blending percentages of over 5%. For bio-ethanol these specifications are currently being adapted to allow percentages of 10%. It is not known when this will come into effect.
3. Which biofuels are available (and what are their associated manufacturing process)?
Only pure plant oil (PPO), biodiesel, bioethanol and biogas are commercially available at this time and will be discussed first.
Bioethanol is the most popular biofuel. It is produced by fermenting plant-based raw materials, such as sugar cane (Brazil), corn (USA) or wheat or sugar beet. Other grains, such as barley and by-products from the food-processing industry (e.g. molasses) are also suitable.
Ethanol is created by the fermentation of plant-based raw materials, whereby yeast converts the sugars into alcohol. This alcohol is then concentrated through distillation, followed by processing via rectification and purification. New techniques are currently being researched for manufacturing bioethanol from cellulose (see also cellulose-ethanol). In Europe ethanol has until now primarily been blended in petrol, in the form of Ethyl Tertiary Butyl Ether (ETBE), which consists of around 50% bioethanol. When blending 5% ETBE in petrol, as happens in France, for example, the percentage of biofuel is thus around 2.5%. During 2006, around 1.56 billion litres of ethanol were produced in the EU. Germany was the largest European manufacturer in that year (431 million litres), followed by Spain (402 million litres).
Pure plant oil (PPO) is made from plant-based oils, just like biodiesel. The production process for PPO is also similar to that of biodiesel (see next section), except that the oil is not subjected to an esterification process. The hot/cold-pressed oil can also be used as a biofuel, but is not suitable for use in an ordinary diesel engine. The engine needs to be modified to allow it to run on PPO. Currently, pure vegetable oils are often used in agricultural machines, particularly in Germany. The use of pure vegetable oil as fuel for adapted private passenger cars or trucks is also most advanced in Germany, with an estimated number of 20,000 adapted passenger vehicles at the end of 2006.
Biodiesel (also fatty-acid methyl ester, FAME) is a diesel fuel with very similar characteristics to conventional diesel. However biodiesel is a methyl ester made from raw materials, such as plant-based oil. In Europe, rapeseed oil (rape oil methyl ester, or RME) is used the most, but other oils, such as sunflower , palm and soy oils, can also be used. Recycled frying fat and animal fats also form good raw materials. The production process consists of the following steps: The oil from the seed is first crushed. The raw oil produced is then purified and then undergoes an esterification process to finally form biodiesel and glycerine. In 2006, the biodiesel production in the EU rose by over 50% compared to 2005 to around 4.9 million tons. In Germany, hundreds of thousands of diesel vehicles are running on pure biodiesel.
Biogas is a flammable gas produced through anaerobic (without oxygen) fermentation of biomass, or the biologically degradable fraction of waste. The raw gas consists primarily of methane (CH4) and carbon dioxide (CO2). After removing the carbon dioxide and further compaction, it is ready to be used as fuel for natural-gas-fueled cars. Most car combustion engines required some modification in order to run on natural gas and/or biogas. At this point in time, much of the commercially available biogas in Europe comes from landfill waste sites. A number of natural-gas filling stations have recently opened up in the Netherlands, and these can also be used to distribute biogas. Several European countries, e.g. Sweden and Switzerland, are already using biogas as a transport fuel, though on a limited scale.
Although not yet commercially available, it is worth noting that other biofuels exist. These are currently still in the research phase. It is expected that such biofuels will perform better with respect to environmental impact and costs.
Cellulose-ethanol is ethanol that is produced from the woody (cellulose) part of crops. A trial plant has been established at Örnsköldsvik (Sweden), where woody residue material will eventually be used to manufacture liquid ethanol. It has a capacity of 300-400 litres of ethanol per 24 hours. The current raw material used in the development process is wood chips from pine trees, but other raw materials such as bagasse from sugarcane, wheat and corn stover, energy grass and recycled waste are also of future interest for the project. Preheating the woodchips via steam up to a temperature of 170-200°C results in a sugar-like hemicellulose, which is then placed in a reactor where enzymes break down the cellulose. The lignin a complex chemical compound which is an integral part of the cell wall of plants is then filtered out, forming a peat-like odourless substance that can be used as a solid fuel. The remaining sugar-like solution flows via a pipeline to large reactor tanks, where the sugar is fermented into ethanol. The yeast is then separated and distilled, thus creating pure ethanol. The difference between bioethanol, from, for example, sugar beet and grain, is that cellulose-ethanol scores better from an environmental point of view, as it reduces CO2 emissions by 80-90%, compared to 30-50% for bioethanol.
This technology was developed by a Canadian biotech company which has built the first demonstration plant for cellulose-ethanol in Ottawa.
The USA has also started a large demonstration programme and, over the next few years, a number of cellulose-ethanol demonstration plants will be built there. The objective of this programme is further development and thus cost reduction of the chemical enzyme-based processes involved in manufacturing cellulose-ethanol.
Bio-FT-diesel, also known as ‘green diesel’ or BtL (Biomass to Liquid), is created by gasification of biomass using the so-called Fischer Tropsch (FT) procedure. The FT process was developed in 1923 by the German researchers Franz Fischer and Hans Tropsch. BtL is still being developed, although the similar processes of GtL (Gas to Liquid, based on natural gas) and CtL (Coal to Liquid, based on pit coal) are already being used commercially in large factories, for example in the Middle East and South Africa.
After pre-treatment, the biomass is placed in a gasification system – this creates a synthetic gas (biosyngas) that, after a cleaning and modification process, is placed in the FT reactor. The released FT waste gas can be used, for example, to generate electricity and after further treatment, the liquid FT products can produce petrol or diesel. In Germany, a trial plant for FT diesel based on biomass has been set up.
Biomethanol used to be known as wood-alcohol. It is a liquid fuel that can be manufactured from synthetic gas, a mixture of carbon monoxide (CO) and hydrogen (H2) that is released during gasification of biomass. A catalytic process can produce methanol from this ‘syngas’. Syngas, and thus methanol, can also be made from fossil fuels, such as natural gas or coal.
A dutch company has converted a methanol production plant that previously ran on natural gas into a plant that (partially) manufactures methanol from biomass.
Like bioethanol, biobutanol is created by fermenting plant-based raw materials (including corn, grain, sugar cane or lignocellulose). Butanol can be widely used in the energy, transport and chemical sectors, and has a number of advantages compared to ethanol. Butanol is easier to blend with petrol, can be transported in existing distribution networks. It also has a volumetric energy content similar to that of petrol. However, with conventional fermentation methods, the amount of butanol produced from glucose is low. This is due to the fact that butanol is toxic for the bacteria, thus it is not possible to achieve high butanol concentrations in the bioreactor. Currently work is being done to improve the methods used in this process technology. In Russia a first Biobutanol Plant is planned to start work by September 2008.
Pyrolysis-oil, also known as bio-oil, is created through pyrolysis of biomass. Heating the woody material with limited oxygen results in the woody molecules being broken down. There is a slow method, where the temperature stays below 280°C, and a fast method with temperatures reaching 1300°C. Several companies have been using the process commercially for a number of years.
Pyrolysis oil is not immediately suitable as a transport fuel, as it needs to be processed to a suitable quality. This process is still in the development phase.
DME, (dimethyl ether), is an organic compound that contains high levels of hydrogen. DME has only recently been viewed as a transport fuel, and until now has mostly been used as a propellant in aerosols. The chemical industry produces DME from methanol, which in turn is obtained from coal, natural gas or biomass. DME is mainly suitable as a diesel fuel, since a diesel engine does not require spark ignition for combustion. Diesel engines are relatively easy to modify. A disadvantage of DME is that it is too aggressive for most plastics and rubbers. As a consequence, connections need to be made of other materials.
Transport, storage and distribution of DME occurs in the same way as LPG. DME is stored under pressure (9 bar). The energy content of DME is almost half that of diesel, which means that motorists need to tank up more often, or install a larger fuel tank.
Hydrogen is an energy carrier used in fuel cells to generate heat and electricity.
There are various techniques available for manufacturing hydrogen from biomass, such as separating the hydrogen from the product gas after biomass gasification (a mixture of H2, CO and CH4) using a ceramic membrane. The hydrogen needs to be cleaned before being used in a fuel cell. Another promising technique for large-scale hydrogen production concerns the gasification of biomass combined with reforming and CO2 removal. In the long term, the so-called supercritical gasification (at high pressure and relatively low temperature) of biomass (residues) offers the best prospects for small-scale production. This is a route that, compared for example to bio-FT-diesel and biomethanol, will require a longer development period.
Like FT-diesel and methanol, hydrogen is also produced from fossil fuels such as natural gas and crude oil. Hydrogen is, thus, not necessarily biohydrogen – this term only applies if it is manufactured from biomass rather than from a fossil fuel.
SNG – synthetic natural gas
Synthetic natural gas contains mostly hydrogen (H2) and carbon monoxide (CO) and is created through gasification of biomass with limited oxygen or (in a two-step process) using steam. After cleaning, the synthetic gas can be upgraded to synthetic natural gas, or SNG. Cars that have been modified to run on gas can also run on SNG.
A Dutch research institute has a trial HTU (Hydro Thermal Upgrading) installation. With its capacity of 100 kilo biomass per hour this HTU plant can produce heavy organic liquid at a temperature of 300-350°C under high pressure. After further processing, this could replace fossil-based diesel. One of the advantages to this HTU process is that it can process wet biomass. It will probably take another few years before the procedure is sufficiently tested and developed enough to produce commercial biodiesel.
4. What are 1st-generation and 2nd-generation biofuels?
Although there is no set definition of 1st and 2nd generation biofuels, these terms are generally used to indicate biofuels that are produced from various types of biomass. Biofuels made from sugar, starch or oil-based crops or residues – such as biodiesel from rapeseed oil or sunflower oil, and alcohol from sugar beets or corn – are known as 1st-generation biofuels. These are already commercially available on a large scale in countries such as France, Germany, Spain, the USA and Brazil. Most 1st-generation biofuels achieve CO2 emission reductions of around 30-50% compared to fossil fuels.
Biofuels that are produced from cellulose and hemicellulose parts of plants or, in simple terms, the woody parts of plants or trees are known as 2nd-generation biofuels. These 2nd-generation biofuels can achieve CO2 emissions reductions of around 90%. In general these biofuels are based on a more advanced production technology (such as Fischer-Tropsch (FT) and cellulose fermentation). Even relatively simple production technologies can result in biofuels with a higher CO2 emission reduction. These, therefore, no longer refer to a pure 1st-generation biofuel, but a 2nd-generation biofuel.
The technologies to produce these biofuels are still in development. Biofuels that can reduce CO2 emissions by around 90% are expected to be available in the next decade.
5. Where do vehicles run on biofuels?
Bioethanol is currently the most popular biofuel in the world. In Brazil, almost all cars run on a blend of petrol with 30-100% alcohol produced from sugar cane. American bioethanol is primarily made from corn or grain. In 2006, the USA used around 19 billion litres of ethanol for the transport sector. The number of filling stations selling ethanol continues to increase. In Sweden, all petrol contains 5% bioethanol. Additionally, there is a network of around 320 petrol stations across the country where motorists can tank their cars on E85 (petrol with 85% ethanol). Several car manufacturers are launching so-called flexi-fuel models of their vehicles, which run on 100% petrol or E85, and everything in between. The engine software automatically adjusts according to the mixture in the fuel tank. Petrol in France contains up to 5% bioethanol or ETBE. A recent legislative change also allows for ethanol to be directly added to petrol. The city of Stockholm has been using modified diesel buses running on 95% ethanol for some time, and the running costs for these special buses are now almost down to the same level as conventional diesel buses.
Currently, pure vegetable oils are most often used for agricultural machines, especially in Germany. The use of pure vegetable oil as fuel for adapted private passenger cars or trucks is also most advanced in Germany, with an estimated number of 20,000 adapted vehicles in use at the end of 2006. Other examples are road-sweeping vehicles in Venlo and Leeuwarden, Netherlands, which run on PPO.
In Europe, the biodiesel blends (especially in France) and biodiesel (particularly in Germany) already have a reasonable market share. In Germany, the infrastructure has also been dramatically changed by the presence of 1,900 filling stations selling biodiesel. Germany also has around 50 trains and over 100 buses running on B100. Since 1997, Vienna has had two household refuse collection lorries, a crane lorry and a bus running on rapeseed. Graz, Austria was the first local authority in the world to have all the buses from the town council transport company running on 100% biodiesel. In Friesland, the Netherlands a holiday company has run all its recreational boats on biodiesel since the summer of 2003. In the USA there are already over 400 car fleets running on biodiesel, and there are over 1000 distributors. For instance, the fleet of the city San Francisco consisting of 1500 vehicles, is running on biodiesel. A large number of car manufacturers are supplying models that can run on biodiesel, without any modifications being necessary. However, the manufacturer’s warranty often imposes conditions such as a maximum percentage of biodiesel.
Many towns have buses running on biogas, Linköping, Sweden for example. A trial project, using six buses, began there in 1991. The positive results from this trial led in 1998 to all 50 public transport buses being converted to biogas. The world’s first biogas train also runs between Linköping and Västervik. Other European towns are now also using buses that run on biogas: in Lille, France, where biofuels have been used since the 1990s. The objective is to eventually convert the entire fleet to run on biogas. Lille has also started a large-scale project to produce biogas by fermenting organic waste at a location alongside the new bus terminal. This biogas will be processed into green natural gas, and will be sufficient for 100-120 buses.
In 2007, the Dutch province of Gelderland started a project where, by the year 2010, 26 buses and over 80 other vehicles will run on biogas, with eight filling stations being built to distribute the fuel.
6. What is the current policy within the European Union?
European policy with respect to the use of biofuels was defined on 8 May 2003 in the EU Directive 2003/30 and will stay in effect untill the proposed new EU Renewable Energy Directive is accepted.
The EU Directive (2003/30) actually contains two directives: A directive to encourage biofuels, and a change in the existing directive concerning excise duty for biofuels (2003/96/EC).
National indicative targets for the amount of biofuels (percentage), 2006-2010
Source: national report under the
EC "biofuels directive".
According to the directive, in 2005 biofuels should replace 2% of the nationally used transport fuels, and from 2010, this should increases to 5.75%. The guideline states that Member States must indicate every year if and how they expect to achieve this target at a national level. In order to achieve this target in 2010, the European Commission has presented a strategy that includes the following seven policy focus points:
1. Encouraging the demand for biofuels.
2. Trying to gain environmental advantages.
3. Developing the production and distribution of biofuels.
4. Expanding the stock of raw materials.
5. Widening the trade options.
6. Supporting developing countries.
7. Research and development.
The European Commission published its ‘Energy Package’ on 10 January 2007. This is an extensive set of measures that together form a new energy policy for Europe. The Renewable Energy Road Map states how the EU countries should achieve 20% lower CO2 emissions. In addition, the Commission also received the support of the EU Member States on 15 February 2007, to challenge the rich European countries to jointly achieve a 30% emissions reduction by 2020. In order to achieve this lower emissions level, politicians are focusing on energy savings and sustainable energy.
According to the proposed new Renewable Energy Directive made public January 2008 by the European Commission, EU Member States will be given a new and binding target (to be met by 2020) to replace 10% of their transport fuels with biofuels. In contrast to the previous Directive (2003/30/EC), the proposed directive sets minimum criteria for the sustainability of biofuels. According to the proposed directive, the minimum requirement for reducing greenhouse gas emissions via biofuels will be 35%. Biofuels that do not meet these criteria will not be counted towards the national target and/or requirement for biofuels, and also ineligible for financial support schemes. In the case of biofuels and other bioliquids the criteria would apply to all installations that are operational on or following the 1 January 2008. For installations commissioned before this date, the minimum criteria will apply from 1 April 2013.
Not only must greenhouse gas emissions meet minimum criteria, preconditions have also been proposed for the type of land on which biomass may be cultivated. These sustainability criteria will apply to biofuels for transport as well as bioliquids in the heating or electricity sectors.
7. What else would I need to consider when changing to biofuels?
First of all, make sure you are well informed about the various types of biofuels. Each biofuel has its own price tag and its own advantages and disadvantages..
For most biofuels - particularly those in the pure form - your car engine will need to be modified. For blends of biodiesel and bioethanol, the engine will need to be modified if:
- there is more than 20% biodiesel in the diesel (due to the viscosity of the biodiesel) or
- blends with more than 10% bioethanol (due to the volatility of the fuel).
Your car will always need to be modified to run on PPO. A conversion kit costs around 800 euro. If you ask an expert to convert the car for you, this will cost between 2,000 and 4,000 Euro. NB: Converting the engine invalidates the car manufacturer's warranty. In many cases the conversion company takes over this warranty. We recommend that you discuss this point beforehand with your car dealer or conversion company.
In short, the amount of modification required, and the costs involved, depend on the biofuel used.
Flexi-fuel cars offer a solution: the car software recognises whatever fuel is in the fuel tank, and runs on a biofuel without problems.
When calculating the environmental impact, the government bases this on the entire production chain, the so-called Well to Wheel (WTW). This means that the calculation does not only consider the environmental impact of the fuel itself, but also the entire production process, up to and including the use of the biofuel. This is necessary to ensure a correct comparison between biofuels and fossil-based fuels and between the various types of biofuels. This may mean that the government uses different figures to the manufacturers. For example, the government includes the cultivation of rapeseed when calculating the environmental impact of PPO, which includes taking into account the land being used and the processing of the fertiliser and the fact that a machine (plus fuel) is required for sowing seeds and harvesting etc.
8. Further information
Biofuel Cities Info Leaflet
Biofuel Cities Background document
Biofuels for Transport ( IEA Bioenergy: T39:2004:01)
Login to access the Biofuel Cities Resource Database
Latest Directive texts
Directive 2003/30/EC from the European Parliament and the Council, dated 8 May 2003, to encourage the use of biofuels and other renewable fuels in the transport sector, 17 May 2003. [PDF 120KB]
Directive 2003/96/EC from the Council, dated 27 October 2003, regarding the restructuring of the community regulations for taxation of energy products and electricity, dated 31 October 2003. [PDF 196KB]