The US Energy Secretary, Federico Pena, outlined a proposal from the US administration that will require US utilities to generate 5.5 per cent of their electricity from renewable sources by 2010, Reuters reports.

The proposal, which will need approval from the US Congress, would provide a boost to the US renewable energy industry. At present, renewable sources account for just over 2 per cent of US electricity output.

The proposal recognizes four renewable sources, solar, wind, biomass and geothermal energy. Hydro projects are not included. Renewable power is expected to cost more than conventional power, but the difference will be small, Pena claimed.