We are concerned that the certification schemes that are intended to prove that biomass used in the UK is sustainably sourced may not be fit for purpose.12 DESNZ told us that they and Ofgem have benchmarked these third–party certification schemes to ensure that they are in line with the sustainability criteria.13 We have also received a written submission from Drax setting out how the Sustainable Biomass Programme (SBP), the largest certification scheme, is underpinned by independent audits which conclude on whether suppliers meet the SBP’s standards.14 However, several stakeholders have written to us expressing concern that such schemes are not robust and do not fully account for changes in forest carbon stocks.15 The NAO report concluded that, in the absence of an evaluation of the effectiveness of these arrangements, the government could not demonstrate that its current arrangements are adequate to give it confidence industry is meeting sustainability standards.16