The US electric grid is outdated and needs a major overhaul if it is to carry electricity generated by renewable energy sources, a senior official with Southern California Edison told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

The Obama administration has called for doubling the amount of US electricity produced by renewable sources, such as wind and solar power, during the next three years to reduce greenhouse emissions that cause global warming.

However, a so-called "smart" grid will be needed to transmit those power supplies from where they are generated in remote areas to consumers and businesses in cities.

"The electricity infrastructure delivering power from a variety of generating sources to our homes, businesses and communities is not suitable for today's needs," said Paul De Martini, SCE's vice president for advanced technology.

"The challenges that face our nation's energy future simply cannot be met by our aging electric grid," Mr Martini said at a House Science subcommittee hearing on how to update the grid.

SCE is a subsidiary of Edison International, one of the largest US electric utilities that serves nearly 14 million people.

Subcommittee chairman Republican Brian Baird pointed out that parts of the US electric infrastructure are almost 100 years old and America's growing demand for electricity, to run computers for example, is straining the system. "In order to improve efficiency of power delivery and incorporate renewable energy technologies we need to modernise our grid," he said.

The problem hit home for Texas oil billionaire T. Boone Pickens, who said earlier this month he was delaying plans to build the world's biggest wind farm in the Texas Panhandle because of the difficulty in building the transmission lines that would carry the power supplies.