Importing biomass involves long supply chains, which make it difficult to be sure that it is produced from genuinely sustainable sources.50 We are also concerned that recent international developments may undermine the system of carbon accounting that underpins the current supply of 39 C&AG’s Report, para 3.2 40 C&AG’S Report, para 1.4 41 C&AG’S Report, para 3.3 42 Climate Change Committee, The Seventh Carbon Budget, February 2025, Section 7.7 43 Bio0012 44 Climate Change Committee, The Seventh Carbon Budget, February 2025, page 272 45 Q 49 46 Q 57 47 Q 57 48 C&AG’s Report, para 3.4 49 Bio0003, Bio0005, Bio0008 50 C&AG’s Report, para 9 13 sustainable biomass.51 Under current carbon accounting rules, emissions from the burning of biomass are accounted for by the country from which the fuel was sourced, an approach we were very critical of in our report on the government’s carbon capture usage and storage programme. The bulk of wood pellets burnt in biomass power generation in the UK come from the US, which has removed itself from the Paris Agreement.52 In written evidence received after our evidence session Drax set out that the US remains party to the United Nations Framework Convention Climate Change which requires that countries submit national greenhouse Gas Inventories in line with international standards.53 51 Q 65 52 Qq 62, 63 53 Letter from Drax, 17 March 2025 14 2 Future interventions Transitional support for Drax, 2027–2031