A renewable energy company backed by Guy Hands' Terra Firma Investments plans to float on London's main market next month.Infinis Energy, which generates up to 621 megawatts of power from 147 land-fill gas sites, onshore wind farms and hydro-electric power plants around the UK, aims to list at least 30% of its shares in London next month.Majority shareholder Terra Firma will reduce its stake as part of the sale to institutions and individual retail investors.The float will give the company, chaired by the former Chief Executive of SSE, Ian Marchant, more ways to raise capital, it said.Marchant said renewable energy will be crucial in helping the UK to secure its energy supplies and meet environmental targets.He said: "Infinis, with a broad portfolio of power plants delivering clean and affordable electricity, is already a significant player in this."Barclays, Deutsche Bank and RBC Capital Markets are running the offer.PW