System analysis of a bio-energy plantation: full greenhouse gas balance and energy accounting (POPFULL)

One of the strategies for mitigation of anthropogenic greenhouse gas emissions that is receiving a lot of attention in this post‐Kyoto era, is the use of bio‐energy as a replacement for fossil fuels. Among the different alternatives of bio‐energy production the use of biomass crops ‐‐ such as fast‐growing woody crops under short rotation coppice (SRC) regimes ‐‐ is probably the most suited, in particular in the EU.

Two issues need to be addressed before the efficacy of bio‐energy for carbon mitigation can be conclusively assessed, i.e. (i) a full life cycle analysis (LCA) of the global warming contribution of SRC, and (ii) and an assessment of the energy efficiency of the system.

The objectives of this project are: (i) to make a full LCA balance of the most important greenhouse gases (CO2, CH4, N2O, H2O and O3) and of the volatile organic compounds (VOC's), and (ii) to make a full energy accounting of a SRC plantation with fast‐growing trees.

The project will involve both an experimental approach at a representative field site in Belgium and a modelling part. For the experimental approach a SRC of poplar (Populus) will be monitored during the course of 1+3 years, harvested and transformed into bio‐energy using two alternative techniques, i.e. a small‐scale gasification and co‐combustion in a large‐ scale electricity plant. Eddy covariance techniques will be used to monitor net fluxes of all greenhouse gases and VOC's, in combination with common assessments of biomass pools (incl. soil) and fluxes.

For the energy accounting we will use life cycle analysis and energy efficiency assessments over the entire life cycle of the SRC plantation until the production of electricity and heat. A significant process based modeling component will integrate the collected knowledge on the greenhouse gas and energy balances toward predictions and simulations of the net reduction of fossil fuel greenhouse gas emissions (avoided emissions) of SRC over different rotation cycles.