The plan put forward by Drax to fit its wood-burning power plant with carbon-capture technology could cost British energy bill payers £31.7bn over 25 years, or £500 a household, according to research. The climate thinktank Ember said that Drax was already on track to earn £10bn in subsidies through energy bills by burning wood chips, and warned that the cost of supporting its future bioenergy plans could climb to more than the cost of subsidising Hinkley Point C nuclear power plant. Ember’s report was based on research commissioned by the government into the cost of bioenergy combined with carbon capture, and assumes that Drax could clinch a subsidy contract to run four generating units at its North Yorkshire plant for the full 25-year lifetime of the project. The report has emerged as the latest point of dispute between the FTSE 100 company and green groups over the UK’s divisive bioenergy strategy. Drax plans to become a “carbon negative” power generator by retrofitting its giant power plant with carbon-capture technology that traps emissions from burning wood chips. It claims that biomass is already carbon neutral because trees absorb as much CO2 to grow as they do when they are burnt. But dozens of green groups have warned government ministers and Drax shareholders against supporting the company’s controversial plans over fears that burning biomass will not deliver “negative emissions” and could prove to be an expensive misstep in the UK’s path to a carbon-neutral economy. Drax has dismissed Ember’s findings because the government study on which it was based used cost estimates for developing a new power plant, rather than retrofitting an existing plant, which it claims would be cheaper. The company added that the report inflated the total potential cost to bill payers by assuming that the subsidy contract would run for 25 years, which is 10 years longer than the period currently envisaged by government officials for carbon-capture projects. The spokesperson said the project “will save the UK more than £4.5bn over the coming decade, as well as removing millions of tonnes of CO2 from the atmosphere and supporting tens of thousands of jobs”. A government spokesperson declined to comment directly on Drax’s plans ahead of a formal planning process. “At every step on the path to net zero, we will put affordability and fairness at the heart of our reforms. The UK only supports biomass which complies with strict sustainability criteria,” the they said.