Task 29, Task 38 and Task 40 Expert Consultation on the sustainability of bioenergy held in Dubrovnik, 25 – 26 October, 2007, and Task 38 workshop on direct and indirect land use change held in Helsinki 30 March-1 April 2009
Prepared by Annette Cowie, Neil Bird and Susanne Woess-Gallasch
The bioenergy industry is expanding rapidly around the globe in response to climate change and rising oil prices. But serious concerns about sustainability of production, off-site environmental and social impacts, and true greenhouse gas balances need to be addressed.
Some so-called “first generation” biofuel systems, such as ethanol from corn, and biodiesel from canola, deliver minor greenhouse gas mitigation benefits when the direct and indirect emissions associated with crop production, processing, and transport are considered. Other biofuel systems such as oil palm grown in South East Asia for biodiesel have apparently greater greenhouse benefits due to efficient high-yielding production systems. However, when indirect impacts of offsite deforestation and loss of soil carbon, especially in peatlands, are brought into the equation the net effect can be negative compared with fossil fuel systems. In addition, expansion of bioenergy systems, involving direct or indirect land use change, can have negative impacts on other environmental attribute, such as catchment water yield and biodiversity.
Furthermore, some current biofuel systems have negative socio-economic consequences, such as increased food prices and displacement of traditional land uses.
Nonetheless, there are some bioenergy options that are environmentally-friendly, can contribute significantly to mitigation of greenhouse gas emissions, and deliver positive social and economic impacts.
Biofuels based on perennial lignocellulosic (woody) feedstocks generally show more promise, both in terms of net greenhouse benefit and other environmental and socio-economic impacts, than many first generation options based on starch and oilseed crops.
The systems with the greatest benefit are those that utilise residues as feedstock, and employ efficient energy conversion technologies such as combustion for heat or co-generation of heat and power.
There is an urgent need for policy development and operational guidelines to support improved sustainability in the bioenergy industry.