Energy from the Sun is only 8 minutes from Earth, but harvesting it is many years away.

A space-based solar power system would require building large solar energy collectors in Earth's orbit. Outside the atmosphere, in constant daylight, the panels would harvest more energy than land-based units.

O. Glenn Smith, a former manager of science and applications experiments for the International Space Station at NASA's Johnson Space Center, wrote an op-ed about space energy in today's Times.

Once collected, the solar energy would be safely beamed to Earth via wireless radio transmission, where it would be received by antennas near cities and other places where large amounts of power are used. The received energy would then be converted to electric power for distribution over the existing grid. Government scientists have projected that the cost of electric power generation from such a system could be as low as 8 to 10 cents per kilowatt-hour, which is within the range of what consumers pay now.

As PV modules get more efficient and lighter, the cost of launching a MW into orbit will decline. Companies involved in NASA's public-private Commercial Orbital Transportation Services initiative are working on precisely that.

Smith recommends that the test of this concept should be energy beamed from the International Space Station to Earth.