Giant solar energy balloons floating high in the air may be a cheap way to provide electricity to areas lacking the land and infrastructure needed for traditional power systems, researchers in Israel say.

The world is racing to find renewable energy sources to replace fossil fuels, and entrepreneurs are scrambling for a slice of a clean energy market that analysts estimate was worth nearly $150 billion last year.

Edison International's Southern California Edison utility has announced plans to build the largest photovoltaic solar system in the US at 250 megawatts, enough for 162,000 homes.

With many of the earth's sunniest spots falling in the middle of the ocean or desert, the balloons, designed by a team from the Technion Institute of Technology, could be used to harness the sun's energy in those remote areas.

However, the application may turn out to have strictly niche appeal given the vast area available in remote locations to park solar panels on rooftops in cities, and on cheap scrub land.

"The idea is to take advantage of the height dimension. When you do that, you save a lot of land resources and can get to places otherwise hard to reach," said Pini Gurfil, the concept's developer.

The helium-filled balloons, covered with thin solar panels, hover as high as a few hundred metres in the air, and are connected via a wire cable to an inverter, which converts the electricity into a form households can use.