The use of wood for electricity generation and heat has grown rapidly in recent years, but its real impact on the climate and on forests is controversial. Like the debate around transport biofuels a few years ago, this has become a highly contested subject with very few areas of consensus. This paper provides an overview of the debate around the impact of wood energy on the global climate, and provides recommendations for policymakers on the appropriate way forward.

Although most renewable energy policy frameworks treat biomass as though it is carbon-neutral at the point of combustion, in reality this cannot be assumed, as biomass emits more carbon per unit of energy than most fossil fuels. Only residues that would otherwise have been burnt as waste or would have been left in the forest and decayed rapidly can be considered to be carbon-neutral over the short to medium term.

One reason for the perception of biomass as carbon-neutral is the fact that, under international greenhouse gas accounting rules, its associated emissions are recorded in the land use rather than the energy sector. However, the different ways in which land use emissions are accounted for means that a proportion of the emissions from biomass may never be accounted for.

In principle, sustainability criteria can ensure that only biomass with the lowest impact on the climate are used; the current criteria in use in some EU member states and under development in the EU, however, do not achieve this as they do not account for changes in forest carbon stock.

Also see The Impacts of the Demand for Woody Biomass for Power and Heat on Climate and Forests, a short synthesis paper including an overview of global patterns of demand and supply for woody biomass for energy, and summarising the impacts of its use on the climate.

Response to Critique

IEA Bioenergy published a critique of Woody Biomass for Power and Heat: Impacts on the Global Climate to which the author provided a written response.