GAVE
Climate neutral gaseous and liquid energy carriers
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GAVE is a government programme that supports the development and introduction of climate-neutral fuels in the Dutch transport sector.
The programme's most important task is to support the implementation of the European Renewable Energy Directive into Dutch national legislation with respect to biofuels.
This EU Directive states that, by the year 2020, 10% of the energy used in the transport sector must be derived from renewable energy.
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| GAVE news |
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How green are biofuels?
Date published: Jul 18, 2005 |
An interesting question confronting many researchers and governments is 'Exactly how green are the various biofuels'. The Flemish research group ENVOC, led by Prof. Jo Dewulf, has developed a new method of critically evaluating the sustainability of biofuels. This is based on a so-called exergy-analysis, which results from the second law of thermodynamics. The method was published in the May 2005 edition of Environmental Science and Technology magazine.
ENVOC has developed a scientific method of critically evaluating the sustainability of biofuels. Biofuel production is partially based on non-renewable energy.
Scientific analysis by Dewulf shows that biofuel production requires up to one-third non-renewable energy. This amount varies from one biofuel to another. This result means we should look specifically and realistically at biofuels as a green or renewable energy.
Dewulf carried out three case studies: Italian bioethanol production from corn, Swedish biodiesel production based on rapeseed, and American biodiesel production from soja. The first remarkable definition concerns the low efficiency of the production chains: the fraction of solar energy that is eventually used in biofuels is only something in the order of 0.5%. This means that considerable (bio) technical research is required in order to produce better results. In comparison: converting solar energy into electricity via photovoltaic cells results in 10-15% efficiency.
A second result of this new evaluation method concerns estimating the use of non-renewable energy sources to produce 'renewable' biofuels. Apparently it takes 1 kWh of non-renewable energy to produce 3-4 kWh of biofuel energy. This 1 kWh of non-renewable energy is required, e.g. to produce pesticides, fertilisers and chemicals. Bioethanol scores better than biodiesel: 4 kWh of bioethanol can be produced using 1 kWh of non-renewable energy, whereas biodiesel production would only result in 3 kWh. In order words: it takes one quarter (bioethanol) and one-third (biodiesel) of non-renewable energy to produce 'renewable' biofuel energy.
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