www.reuters.com
Jun 16, 2009
Solar from space: It may sound like a bad sci-fi movie, but a growing number of companies think it could solve the world's energy crisis. Among them is Everett, Wash.-based PowerSat Corp., which said today it's filed a provisional patent for two technologies it claims could help make the transmission of solar energy from space more cost-effective. CEO William Maness also told us that the 8-year-old company has received commitments for $3-$5 million in angel funding, which it's using to develop wireless power demonstrations on Earth, and is currently in negotiations for a first venture round in the single-digit millions.
The PowerSat news comes after Manhattan Beach, Calif.-based Solaren, another space solar company, in April signed a deal to provide power to northern California utility PG&E. And Swiss startup Space Energy recently said it's working to launch a prototype satellite into space in 2-3 years.
Solar In Space
Space solar promises virtually unlimited power, with no carbon dioxide emissions. Undiminished by atmosphere or cloud cover, the sun's energy is five times more powerful than can be found on even the brightest desert on the planet, according to PowerSat's web site. And since the sun shines at full power all the time, solar energy-capturing satellites — called powersats — can receive more than 25 times as much power as a ground-based system of the same size, the company says.
Here's how space solar would work: Power satellites armed with solar arrays would generate direct-current electricity, then convert that electricity into radio-frequency energy, which they would transmit the same way that radio travels to your car. But instead of using electricity to transmit information, as a radio signal does, these satellites would be sending the electricity itself. The radio frequency would get converted back into DC electricity at the receiver on the ground.
The huge potential has been apparent for decades, but space solar faces plenty of challenges. The biggest challenge so far, says Maness, is that it's considered a risky investment. Nobody wants to invest billions of dollars to launch unproven technology into space, but it's hard to prove the technology works without trying it out on location. Those billions of dollars represent another major hurdle. Even SpaceX's target price of $500 per pound, with its Falcon 9 spaceship, is about 20 percent too high to make a commercial space-solar project viable, and other launch estimates "aren't even in the ballpark," Maness said.
PowerSat’s Innovation
Now, PowerSat has come up with two technologies that it claims could shave off roughly $1 billion in launch and operation costs for a 2.5-MW power station. The first of these is called BrightStar. Instead of one large satellite, Brightstar uses a cluster of hundreds of small ones, which work together — similar to cloud computing — to transmit the power as a group.
The second technology, called Solar Power Orbital Transfer or SPOT, uses the same solar array needed for wireless power transmission to power the electronic thrusters that boost the satellites from what's called "low Earth orbit," which is 300-1,000 miles up, to "geosynchronous Earth orbit," which is 22,236 miles up. Other satellites use a chemically fueled "space tug" to get to the geosynchronous level, and eliminating that power source reduces the weight of a satellite by 67 percent, dramatically decreasing launch costs, Maness said.
The company is developing a 10-kW demonstration project with unnamed potential clients. In about three years, PowerSat hopes to launch a low-earth-orbit project, which will cost about $100 million. And within five years, the startup plans to look for a partnership with a utility, a public-private partnership involving the government or an initial public offering to raise the money for a full-sized project.
PowerSat plans to launch a prototype project into geosynchronous orbit in 2015 and to reach full power production between 2019 and 2021. It expects the smallest economically viable project, with a capacity of 2.5 gigawatts, to cost between $4-$5 billion.
Raising that kind of money, even with proof in place, will be a colossal task. And a long path — the company hasn't even raised its first single-digit million venture round, although it has closed angel funding. It's clear that while space solar may be flying closer, it still has a long way to go.
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