Green taxes will cost the average household almost £150 from next year, according to energy firms.
Prof Helm said this was “significantly higher than it needs to be” to meet the Government’s objectives of cutting down on the use of fossil fuels and promoting renewable energy.
He was asked to undertake the research after Theresa May, the Prime Minister, vowed to tackle “rip-off” bills. However, the industry expert placed the blame on the Government’s own policies.
“Significant institutional reform” should be brought in to reduce the Government’s role and allow the market to function efficiently, Prof Helm said.