Biofuel: liquid fuel for transport produced from biomass, for example: biogasoline, biodiesel and other liquid biofuels
Advanced biofuel: biofuel which is produced from materials such as algae, waste, residues, non-food cellulosic material and ligno-cellulosic material
Conventional biofuel: biofuel which is produced from food or feed crops
Biogasoline includes bioethanol, biomethanol, bioETBE (ethyl-tertio-butyl-ether produced on the basis of bioethanol; the percentage by volume of bio-ETBE that is calculated as biofuel is 47%) and bioMTBE (methyl-tertio-butyl-ether produced on the basis of biomethanol: the percentage by volume of bioMTBE that is calculated as biofuel is 36%).
The mandatory targets for the use of renewable energy in transport has boosted the use of biofuels in the EU reaching 564 PJ in 2012. The NREAPs forecasted a use of biofuels of about 1216 PJ Mtoe in 2020, representing more than 90% of the renewable energy expected to be used in transport. Today, biofuels are produced largely from food-crops. A recent European Council decision limited the use of conventional biofuels to 7% of the energy use in transport for 2020 (European Council, 2014); the rest should come from 2nd generation lignocellulosic biofuels.
In total, we estimate that about 40 million tonnes of biomass feedstock were used in 2012 to produce biofuels. Significant amounts of by-products of bioethanol and biodiesel were generated; about 3.5 million tonnes of Distillers Dried Grains (DDGs), and about 12 million tonnes of oil meals (which are both generally used for feed). For 2020, about 63 million tonnes of biomass feedstock alone could be used for food crop-based biofuels productions, based on the projections of the NREAPs. In addition about 15 million tonnes of lignocellulosic biomass (wood, straw, etc.) would be needed to produce lignocellulosic biofuels. The production of by-products from bioethanol and biodiesel in 2020 is expected to reach 20 million tonnes of Distillers Dried Grains (DDGs), and about 45 million tonnes of oil meals (some of which produced outside of the EU), respectively ( Scarlat et al., 2015).
Biofuels drivers include:
- Increase of security of energy supply;
- Reduction of dependence on fossil fuels;
- Reduction of greenhouse gas emissions e.g. CO2;
- Reduction local air pollution;
- Protection of soil and groundwater through the use of biodegradable products;
- Reduction of health hazards by using non-toxic products.
There is great political and media attention now focused on biofuels and the issues related to food security, food prices, effects on biodiversity and perceived CO2 emission advantages over fossil fuels. Provided that farmers and plant operators adopt sustainable energy crop production, thoughtful management & planning as well as sourcing (where available) energy needs for biofuel production from waste plant residues, then there should be no negative environmental effect. On the other hand job creation and the development of rural economies is an important benefit of biofuel production. Furthermore, advanced biofuels are starting to be produced in a profitable manner and more research and technological advances will make them more competitive.
The EC has established a set of sustainability criteria in the Energy and Climate Package, which follows on from the Renewable Energy Roadmap. Articles 17, 18 and 19 of Directive 2009/28 EC forbid the use of lands with high biodiversity, land with high carbon stock, or establish the minimum greenhouse gas savings. These criteria apply since December 2010. Moreover, the EC supports the creation of private volunteer sustainability schemes, essential in order to be counted for the national goals and be qualified to receive government support. Currently the Commission has approved 17. The revision of Directive 2009/28/EC shall increase this criteria and take into consideration the issue of Indirect Land Use Change.
European regulatory framework
A precise regulatory framework for biofuel development in Europe exists since the beginning of the 1990s. The first measures date from 1992 with a section of the CAP (Common Agricultural Policy) that gave member States the possibility of growing non-food crops on fallow lands and exempting biofuels from taxes in respect of price competition. The principle of each country being assigned production quotas dates back to this same period and it still in use for some of the member States. In 2003, European texts appeared that reinforced the conditions of development of the biofuels sector. The first was the directive 2003/30/CE of 8 May 2003 that targeted promoting the use of biofuels in transportation. In the end of 2007, the European Commission presented its Climate and Energy package which contained Directives 2009/28/EC on Renewable Energies and 2009/30/EC on Fuel Quality. They stablished a 10% goal of renewable energies share in the final consumption in the transport sector by 2020 and the reduction of greenhouse gas intensity in fuels of a 10% by 2020 too.
In February 2006, the Commission released the EU Strategy for Biofuels which contained further specification following on from the Biomass Action Plan (BAP), released in December 2005. The report is based upon a threefold objective: further promotion of biofuels in the EU and in developing countries, preparation for the large-scale use of biofuels, and heightened cooperation with developing countries in the sustainable production of biofuels. In 2009 Fuel Quality and Renewable Energy Directives enter into force, establishing goals and governance system, setting up sustainability criteria, promoting private schemes and defining the rules that might apply the national support for renewables. Moreover, the EC also proposed a revision of the 2003 Energy Taxation Directive in order to define new rules aim to restructure the way energy products are taxed to remove current imbalances and take into account both their CO2 emissions and energy content. The lack of consensus within the Council has stopped this revision.
Most promising biofuels for transport
- Biodiesel is a methyl-ester produced from vegetable or animal oil, of diesel quality to be used as biofuel. Note the difference with pure vegetable or animal oil, which can be used in adapted diesel engines as well. Application: compression-ignition engines.
- Pure vegetable oil is oil produced from oil plants through pressing, extraction or comparable procedures, crude or refined but chemically unmodified, when compatible with the type of engines involved and the corresponding emission requirements. Applications: direct use in adapted CI-engines.
- Bioethanol is ethanol produced from biomass and/or the biodegradable fraction of waste, to be used as biofuel. Bio-ethanol can be produced from any biological feedstock that contains appreciable amounts of sugar or other matter that can be converted into sugar, such as starch or cellulose. Also ligno-cellulosic materials (wood and straw) are often hinted at, but their processing into bio-ethanol is more expensive. Application: Spark ignition (SI) engines.
- Bio-ETBE (ethyl-tertio-butyl-ether) is ETBE produced on the basis of bioethanol. The percentage by volume of bio-ETBE that is calculated as bio-fuel is 47%. Application: SI-engines (blends with petrol).
- Biogas is a fuel gas produced from biomass and/or the biodegradable fraction of waste, that can be purified to natural gas quality, to be used as biofuel, or wood gas. This definition covers two main gases derived from different processes:
- Methane rich (55-60% by volume) gas produced by means of anaerobe digestion of wet biomass.
- Carbon monoxide rich gas made via thermal gasification. Also some hydrogen and methane are present in this gas type.
- Methane rich gas made via thermal gasification, followed by a methane shift reaction. After desulphurisation, biogas can be used directly to fuel adapted SI and CI engines. Alternatively methane can be separated out from biogas to be fed into the distribution grid for natural gas, and thus it could be used as a transport fuel in the same manner as fossil compressed natural gas. Application: SI-engines.
- Bio-methanol is methanol produced from biomass, to be used as biofuel. Methanol can be produced from syngas (a mixture of carbon monoxide and hydrogen). Virtually all syngas for conventional methanol production is produced by steam reforming of natural gas into syngas. In the case of bio-methanol, a biomass is gasified first to produce a syngas from which the bio-methanol is produced. Application: SI engines (blended with petrol), CI- engines (pure), fuel cells.
- Bio-MTBE (methyl-tertio-butyl-ether) is a fuel produced on the basis of biomethanol. The percentage by volume of bio-MTBE that is calculated as biofuel is 36%. Application: SI-engines (blends with petrol).
- Biodimethylether (DME) is dimethylether produced from biomass, to be used as biofuel. Bio-DME can be formed from syngas by means of oxygenate synthesis. It has emerged only recently as an automotive fuel option. Storage capabilities are similar to those of LPG. Application: CI-engines.
- Synthetic biofuels are synthetic hydrocarbons or mixtures of synthetic hydrocarbons, which have been produced from biomass. This broad definition includes Fischer-Tropsch Diesel which is manufactured from syngas, using a large-scale production process. Syngas is usually produced from coal or natural gas via auto-thermal reforming, but can also be derived via gasification of biomass or gasification of pyrolysis oil. The process was applied in times of mineral oil scarcity. Application: CI-engines.
- Bio-hydrogen is hydrogen produced from biomass, and/or from the biodegradable fraction of waste, to be used as biofuel. Application: fuel cells.
European Commission (2014), Environmental Technologies Action Plan (ETAP), 〈http://ec.europa.eu/environment/ecoap/about-action-plan/etap-previous-action-plan/index_en.htm〉, 2014 .