There has been a growing interest in the use of bioenergy with carbon capture and storage (BECCS) to achieve a net reduction in greenhouse gases. BECCS involves the combustion of biomass to generate energy, using trees and grasses grown on both agricultural land and marginal land unsuitable for food crops. The resulting CO2 emissions are captured, compressed, and transported to suitable underground storage sites. BECCS is an example of a Negative Emission Technology (NET), with others including the direct capture of CO2 from the air, afforestation and carbon capture by trees, and pulverization of rocks to enhance the natural weathering process and CO2 uptake. These are controversial technologies because they are largely untested at scale and because we have limited understanding of their wider impacts on society and the environment.
Achieving the Paris Agreement targets requires nations to reach net zero emissions later this century, but this is challenging because some economic sectors are very difficult to fully decarbonize. This is why the UK, along with a number of other nations, will deploy NETs in order to achieve their commitment to a net zero economy by 2050. BECCS features heavily in the energy scenarios designed to meet these net zero targets and the UK is unlikely to reach net zero without significant deployment of BECCS, estimated to be as high as 15 GW (capturing 67 Mt of CO2 per year) by the UK Committee on Climate Change. However, the models used to generate these BECCS scenarios do not address environmental and social implications of BECCS at the regional scale and rarely consider the environment. One way to address this question is to quantify the consequences of BECCS deployment on a basket of ecosystems services – the benefits derived from the environment that make human life possible and worth living.
In this new publication, Donnison and colleagues show that positive ecosystem service benefits of BECCS using domestic biomass do exist and include increased flood protection and carbon sequestration, depending on location, with Drax identified as one of the most positive UK sites for the delivery of ecosystem service benefits. However, these benefits decline with size with 1 GW BECCS being significantly less beneficial to the environment than 500 MW, suggesting that future BECCS requires site-specific ecosystem service valuations to assess trade-offs and co-benefits of this NET and that smaller power plants are preferred over large infrastructures.
“The novelty of this study is that for the first time we have managed to quantify the impact of BECCS at a regional scale, on the environment – showing perhaps surprisingly that BECCS can have significant positive impacts because long-lived trees are good for soil carbon and flood protection. However, this net benefit depends very much on where the BECCS power station is sited and consistently, in our study, declined as the capacity of the power station increased. These are very significant findings for policy makers if BECCS, as predicted, is to play a big role in the UK strategy to get to net zero by 2050,” said PI Gail Taylor.