Wood-burning power generation, even with carbon capture and storage, may not be the climate-friendly solution governments and energy companies have been promoting. A recent study published in Nature Sustainability reveals that burning wood for power can be worse for the climate than burning gas, even when the resulting carbon dioxide emissions are captured and stored. This finding challenges the notion that bio-energy with carbon capture and storage (BECCS) can provide clean baseload power, substituting for gas and coal, and even resulting in "negative emissions" by growing replacement forests. The research, led by Tim Searchinger from Princeton University, highlights several critical issues with this approach.
One major problem is the time it takes for BECCS systems to become carbon negative. The study found that it could take up to 150 years for these systems to offset their emissions, primarily due to the slow regrowth of forests and the damage caused by converting existing land uses, such as savannah, pasture, or cropland, into biomass production. Even when half of the wood is sourced from waste and fast-growing plantations, the models indicate that it would still take decades to reach "negative emissions".
The study also reveals that most of the emissions from burning wood occur before it reaches the power plant, making them difficult to capture. Wood emits twice as much carbon per unit of energy produced as fossil gas and is far less efficient in generating energy. This means that the initial burning of wood contributes significantly to carbon emissions, which cannot be offset by the eventual carbon capture and storage process.
Searchinger's recommendation is clear: "Governments should not subsidize burning wood from existing forests, with or without carbon capture and storage." He argues that this practice will increase carbon emissions for decades, even compared to doing nothing, and will significantly raise energy prices. The study's findings have sparked a debate among campaigners and environmental organizations, with Greenpeace UK's Douglas Parr stating that burning and burying tree emissions is a "bad idea" and that removing trees from one country to balance carbon budgets leaves the world poorer.
The Natural Resources Defense Council's Matt Williams supports this view, emphasizing the UK's better-off position without BECCS. He advocates for finding other genuinely clean sources of power that do not rely on imported fuels. The controversy surrounding BECCS has led Drax, the main generator of biomass electricity in the UK, to "pause" its investment in BECCS, citing uncertainty over government subsidies. However, the company's spokesperson argues that they source biomass from well-managed, sustainable forests and adhere to strict sustainability requirements.
The debate over BECCS continues, with the UK government's plans to reach net zero by 2050 relying on this technology. The Renewable Energy Association's Trevor Hutchings acknowledges the complexities and risks of BECCS but emphasizes the importance of achieving net zero targets. The Department for Energy Security and Net Zero, however, has rejected the report's findings, stating that no final decisions have been made regarding BECCS projects and that any support would need to meet sustainability criteria and provide value for money.
In conclusion, the study's findings raise significant questions about the effectiveness of BECCS as a climate solution. While the technology holds promise, the long-term challenges and uncertainties associated with wood-burning power generation, even with carbon capture, cannot be ignored. As the world seeks to transition to a low-carbon future, it is crucial to carefully consider the environmental and economic implications of various energy sources and to prioritize genuinely sustainable and efficient alternatives.
