Influence des bilans énergétiques et CO2 sur les filières d’approvisionnement en biomasse pour des projets d’énergie verte

Influence of energy and CO2 balances on the biomass supplying methods for green energy projects

Context

The setting up of policies aiming to reduce fossil CO₂ emissions, codified in the protocol of Kyoto leads to the recent development of many green energy projects. Among those, contrary to the wind or hydro-electricity, biomass plays a specific role as it is not considered as totally neutral. Indeed, bioenergy causes emissions during the production, harvesting, transportation and conditioning.
The relative advantages of bioenergy projects are therefore subjected to a lever effect influenced by CO₂ balances. It appears that these have a great variability that still amplifies the lever effect.
Therefore, it seems that the choice of a green energy project, of its biomass source and of its supplying method can be strongly influenced by these balances. This study aims at proving this assumption and at analysing its mechanisms.

Objectives

To bring forward the influence of energy balances and CO₂ on the choice of biomass supplying methods for green energy projects by modelling the supply chains and their CO₂ balances.

Description of tasks

- Assessment of the biomass resource - modelling ;
- determination of mobilization methods – techno-economic strategies ;
- Energy and CO₂ balances of the supplying methods - modelling ;
- optimisation and economic sensibility analysis of the supplying methods within the framework of the carbon market.

Expected results

This work is the subject of a doctoral thesis supervised by Professor Rolf Bjorheden of the Polytechnic University of Vaxjö (Sweden).
The Centre invested in a new wood harvesting pilot unit for energy (this station often plays an essential part in the balance and is eminently variable). Various measuring equipment as well as a software specially developed for the occasion make it possible to analyse with a great precision the energy flows and CO₂ at play.

Results obtained

The study and optimisation of supplying chains of wood power units in Wallonia made it possible to define optimal strategies of mobilization. Among the three type methods obtained, it was calculated that the less mechanized one had an emission rate of CO₂ of 64,4 kg per ton of dry matter while the most intensive in capital produced 43,5 kg. Experiments on test rigs showed an influence of the initial diameter of the biofuel on the emissions, being lower than 7 cm of diameter.

Partners

International Energy Agency, Texas A&M University (USA), Växjö University (Sweden), Canadian Forest Service (Canada), CSIRO Forestry and Forest Products (Australia), Danish Forest and Landscape Research Institute (Denmark), Norwegian Forest Research Institute (Norway), USDA Forest Service (USA), Vandaele

CRAW off coordinator

VAN_BELLE Jean-François (Attaché scientifique)
Département Génie rural
Chaussée de Namur, 146
B-5030 Gembloux
Téléphone direct :62 71 77
Téléphone département :+ 32(81) 61 25 01
Fax département :+ 32(81) 61 58 47
E-mail :van_belle@cra.wallonie.be