(2021) Greenhouse gas emissions from burning US-sourced woody biomass in the EU and UK

Report from the Woodwell Climate Research Center

As more and more countries adopt climate targets to achieve net zero greenhouse gas emissions, the relevance of forests as stores of sequestered carbon has increased. However, the growing use of forest biomass to generate electricity and heat has raised concerns over the immediate emissions resulting from burning wood.

Many national and intergovernmental policy frameworks, including those of the EU and UK, currently treat biomass energy as zero-carbon at the point of combustion. Accordingly, they grant it access to financial and regulatory support available for other renewable energy sources. These incentives have driven a rapid increase in the consumption of biomass for energy, even though its combustion may increase atmospheric concentrations of carbon dioxide (CO2) for years or even decades to come.

This report examines the issue in relation to one particular source of woody biomass: wood pellets sourced from the US that are burnt for electricity and combined heat and power (CHP) in the EU and UK. Although wood pellets represent only a proportion of the total woody biomass consumed for energy in the EU – and of forest harvests in the US – the market has grown rapidly in recent years. US-sourced pellets account for the majority of wood pellet imports to the UK and are an important source for the EU.

In 2019, according to our analysis, US-sourced pellets burnt for energy in the UK were responsible for 13 million–16 million tonnes of CO2 emissions, when taking into account emissions from their combustion and their supply chain, forgone removals of CO2 from the atmosphere due to the harvest of live trees and emissions from the decay of roots and unused logging residues left in the forest after harvest. Almost none of these emissions are included in the UK’s national greenhouse gas inventory; if they were, this would have added between 22 and 27 per cent to the emissions from total UK electricity generation, or 2.8–3.6 per cent of total UK greenhouse gas emissions in 2019. This volume is equivalent to the annual greenhouse gas emissions from 6 million to 7 million passenger vehicles.

Emissions from US-sourced biomass burnt in the UK are projected to rise to 17 million–20 million tonnes of CO2 a year by 2025. This represents 4.4–5.1 per cent of the average annual greenhouse gas emissions target in the UK’s fourth carbon budget (which covers the period 2023–27), making it more difficult to hit a target which the government is currently not on track to achieve in any case.

(2021) Greenhouse gas emissions from burning US-sourced woody biomass in the EU and UK.pdf