Solar Power from Space

One possibility is to convert stored solar energy to microwave radiation and beam it down to a combination rectifier-antenna, called a rectenna, located in an isolated area. The rectenna would convert the microwave energy back to DC (direct current) power. According to Marzwell, the dangers of being close to the microwave beam would be similar to the dangers of cell phone transmissions, microwave ovens or high-power electrical transmission lines.

"There is a risk element but you can reduce it," said Marzwell. "You can put these small receivers in the desert or in the mountains away from populated areas."

Lasers are also under consideration for beaming the energy from space. Using lasers would eliminate most of the problems associated with microwave but under a current treaty with Russia, the US is prohibited from beaming high-power lasers from outer space.

All in all, the positive aspects of such a system appear to outweigh the negative ones. Space-based solar power offers energy from an unending source with no emissions and very little environmental impact.

According to Marzwell, using today's technology a space solar power system could generate energy at a cost of 60 to 80 cents per kilowatt-hour. This estimate includes construction costs for the first system.

"We believe that in 15 to 25 years we can lower that cost to 7 to 10 cents per kilowatt hour," said Marzwell. The market price today is around 5 to 6 cents per kilowatt-hour.

"With funding and support, we can continue developing this technology," said Marzwell. "We offer an advantage. You don't need cables, pipes, gas or copper wires. We can send it to you like a cell phone call -- where you want it and when you want it, in real time."

Mankins agreed. With a dedicated effort and resources, he says, space solar power --just a dream today-- could become a reality in the decades ahead.