If I told you that the US military has just unveiled plans to fire a beam of high-energy microwaves to Earth from space, you might well hide under your bed. But this is no "death ray". In fact, it's not even a weapon. It's a formula for world peace and the end of climate change.

Now I know what you're thinking. "Hang on, I know what the US military really means when they talk about bringing peace' to the world."

True, I admit that if you were hoping to save the planet, the Pentagon might not be the first door you would knock on. So it comes as a pleasant surprise that, from the offices of the US Department of Defense, an elegant and inspiring blueprint for peace on Earth has emerged, in the form of a giant microwave beam.

Ever since the Sputnik satellite was launched 50 years ago, scientists have dreamed of building "orbiting power stations", by launching acres of solar panels and beaming electricity back to Earth. Putting "solar factories" in space would allow them to operate 24 hours a day, offering a consistent, limitless supply of green energy.

These dreams were always shot down by the costs - exorbitant when compared with the plentiful reserves of fossil fuels. Now, with spiralling oil prices and the threat of runaway climate change, the balance has tipped, according to the National Security Space Office, part of the Department of Defense. Its study claims that space-based solar power (SBSP) could be economically competitive in the near future. In just a year, it calculates, satellites orbiting in a continuous sunlight could generate energy nearly equivalent to all of the energy available in the world's oil reserves. Not only might that put the brakes on global warming, it says, it could help to stifle the wars and political tension that the oil trade creates. The result - a peaceful world.

"This is a solution for mankind," said former astronaut Buzz Aldrin, chairman of the spaceflight advocacy group, ShareSpace Foundation, at the unveiling of the report in Washington. The report urges the US government to invest £5bn in a pilot project, to spur private investment in the concept. It argues that SBSP could generate so much power it could transform the gas guzzling United States into an energy-exporting nation.

The power plant would beam its energy in a microwave beam, which would hit a receiving antenna complex, known as a "rectenna", which would convert it into electricity. But the platforms would be much larger than anything yet constructed in space - requiring an enormous growth and advancement in space transport. Then there's the timescale. It would take at least 10 years before energy could be produced in significant quantities. Finally, what about the possibility that the beam could be attacked, captured and used as a weapon?

Ah well, say the authors, this is the clever part. If the US invites other space powers to get involved, they'd have no reason to object. Clean energy for everyone and not a sniff of a war anywhere.

Bring on the death rays, I say.