In the framework of this Carbon Labelling Initiative supportable methodologies for the quantification of carbon life cycle reductions were identified in co-operation with activities and methodologies by European and worldwide expert groups from research, industry and politics involved in carbon life cycle assessments. An application of carbon LCA methodologies within the Carbon Labelling project was necessary in order to define scientifically proven carbon reduction numbers. Therefore, approaches of SenterNovem (NL), ifeu Institute (DE) and Imperial College (UK) were compared to each other and to the methodology proposed by the European Commission.
The following publications summarize different GHG calculation methodologies:
In Germany, the CO2Star label was introduced by the fuel retailor Q1 in July 2007. The label promoted CO2 reductions of 60% for using biodiesel instead of fossil diesel. This reduction number only applied for biodiesel from rapeseed (rapeseedmethylester, RME) produced in Germany and was supported by the Advisory Board.
In the following months, GHG calculation tools have been developed stating considerably lower default and typical values for biodiesel produced from rape seed in Europe, namely a CO2 reduction of 35.8% for the Dutch calculator, and 21.8% for the UK calculator. In the meantime, a simplified approach was also adopted within the proposed EU Renewable Energy Directive in order to limit the burden for the reporting of GHG emissions under biofuel sustainability schemes to be introduced in Europe.
One of the major drivers of biofuel developments worldwide is the concern about global climate change which is primarily caused by burning fossil fuels. There is substantial scientific evidence that accelerating global warming is caused by increasing greenhouse gas (GHG) emissions. Greenhouse gases are carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4) and several other compounds. As their relative potential for causing global warming differs, it has become practice to weight their emissions according to their global warming potentials (GWP) over 100 years and then aggregate them to CO2 equivalents. GWP is an index for estimating relative global warming contribution due to atmospheric emission of one kg of a particular greenhouse gas compared to emission of one kg of carbon dioxide. GWPs calculated for different time horizons show the effects of atmospheric lifetimes of the different gases. For the assessment of GHG impacts of biofuels mainly CO2, N2O and CH4 are relevant. In the Carbon Labelling Project CO2 equivalents are used.
Carbon Life Cycle
As biofuels are produced from biomass, the combustion of these biofuels principally is considered to be CO2 neutral. During the combustion process about the same amount of CO2 is being set free, that has been bound from the atmosphere during photosynthesis and growth of the plants. Therefore the carbon cycle seems to be closed.
But, apart from direct GHG emissions from burning fuels (which are not accounted in the GHG balance of biofuels as they are renewable), there are significant additional emissions which are associated with all stages of the biofuel life cycle. For biofuels these emissions are created during cultivation, transport, conversion process and distribution. Thereby emissions from feedstock production are the largest ones in the life cycle. Nevertheless, it has to be considered, that the life cycle of fossil fuel production produces considerable amounts of emissions, too.
As inputs for the production of biofuels are usually still of fossil origin, the impact on climate of biofuels greatly depends on the fossil energy balance of biofuel production. The combustion and use of fossil sources emit CO2 which was bound for thousands of years in the earth.
In the Carbon Labelling Project the whole life cycle of biofuels is included for calculationg CO2 numbers.
GHG calculator of HGCA/Imperial College
The Biofuels GHG calculator developed by Imperial College London and the Home Grown Cereals Authority (HGCA) is a spreadsheet-based Excel tool for calculating the GHG emissions resulting from the production and use of wheat-based bioethanol and rapeseed biodiesel in the United Kingdom. It uses input data describing the entire production chain for any given batch of these biofuels, calculates the GHG emissions and compares the emissions with those produced from the production and use of an equivalent quantity of petrol or diesel. It is based on standard life-cycle analysis (LCA) principles, using user input or default data to produce inventories of inputs, outputs and GHG emissions for all supply chain stages. The resulting well-to-tank (WTT) emission figures allow appropriate comparisons between different biofuels and between biofuels and fossil fuels. For each WTT calculation, the calculator guides the user through a set of steps in a life cycle inventory, before presenting the results and allowing for examination of the detailed calculations. Each step of the calculations is presented on a separate page, so that users may more easily focus on those steps of most interest to them and simply accept defaults for those steps of less interest or over which they have little control. Thus a farmer can focus on analysing the GHG impacts of farm level choices, while simply accepting suggested defaults for fuel production plant and other supply chain parameters.
If default values are used in this tool, 24.1% reduction in green house gases are calculated for biodiesel from rapeseed. Producers are encouraged to insert actual values in order to increase the reduction number.
Senter Novem and Ecofys, The Netherlands, developed a "CO2 Tool" for determining greenhouse gas emissions from the production of transport fuels, electricity and heat from biomass. The CO2 bioenergy tool allows you to calculate greenhouse gas emissions from the production of electricity, heat and transport fuels made from biomass. This webpage of Senter Novem (http://gave.novem.nl/gave/index.asp?id=47) provides answers to the following questions:
What is the CO2 bioenergy tool?
Why was the CO2 bioenergy tool developed?
How was the CO2 bioenergy tool developed?
How were the stakeholders involved in the development of the CO2 bioenergy tool?
Who uses the CO2 bioenergy tool?
How does this fit in with other activities within the EU?
What are the results?
How do the results compare to the default values defined in Annex VII of the European guideline proposal for renewable energy?
What are the next steps to be taken over the coming period?
Why is the Dutch CO2 bioenergy tool being publicised now?
Where can I find more information on the CO2 bioenergy tool?