U.S. start-up Joule Biotechnologies hopes to make commercial amounts of motor fuel by feeding engineered organisms high concentrations of carbon dioxide and sunlight, its top executive said.

The United States could save about $600 billion in energy costs by 2020 if it hiked annual efficiency spending about five-fold, business consultants McKinsey and Co said in a report on Wednesday.

The U.S. electric grid is outdated and needs a major overhaul if it is to carry electricity generated by renewable energy sources, a senior official with Southern California Edison told Congress on Thursday.

Alternative energy jobs can provide vocations across many sectors of the economy but policy to spark them can take years to develop, U.S. governors told a Senate committee on Tuesday.

China has launched an unprecedented plan to offer hefty subsidies to independent solar power projects, a move that sparked a rally in the sector on Tuesday.

Shares of Suntech Power Holdings Co Ltd soared 9 percent, Yingli Green Energy Holding Co Ltd climbed 10 percent, Trina Solar Ltd rose nearly 9 percent and JA Solar Holdings Co Ltd was trading nearly 8 percent higher.

The Environmental Protection Agency on Thursday said it was extending the comment period on a draft rule that aims to cut greenhouse gases emitted by biofuels.

The proposed changes to the 2007 U.S. Renewable Fuel Standard attempt to make production of corn-based ethanol more efficient and increase output of advanced biofuels.

The dramatic growth in wind turbines around the British Isles may lead to huge spikes in power prices by 2030 and threaten the viability of backup plants needed for calm periods, according to Poyry Energy Consulting.

Norway's government proposed a new law on Friday to develop sea-based wind power as part of a plan to diversify from offshore oil and gas toward renewable energy.

"Offshore wind energy may become the next adventure for the Norwegian industry and energy sector," Oil and Energy Minister Terje Riis-Johansen said in a statement of a draft bill presented by the center-left government.