Konferensartikel

Most quantitative assessments of biomass fuels or biofuels assume that bioenergy is inherently carbon neutral; that biogenic emissions of carbon dioxide should be excluded from a carbon footprint. This ‘carbon neutral’ assumption makes an enormous difference in carbon accounts and in the policies that those accounts would suggest. For instance; if harvested logs burnt as fuel are considered carbon neutral; their carbon footprint is far lower than that of natural gas. However; if the logs’ biogenic carbon emissions are counted; then their carbon footprint is much higher than gas’s. Moreover; this can lead to absurd conclusions. If carbon neutrality is presumed; it makes no difference to a carbon footprint if a forest is standing or if it has been chopped down for fuel wood. Since the mid-1990s; some researchers have contradicted the ‘carbon neutral’ assumption; and their view that biogenic emissions should be counted has begun to attract significant attention of policy makers. This paper reviews the history and current state of biogenic-carbon accounting rules; including the ISO/CEN rules being developed under the EU Renewable Energy Directive. Without taking sides; it will define the debate for researchers and policy-makers; reflect on its significance and suggest possible means of resolution.

Biofuels; carbon accounting; carbon neutral