The sun doesn’t always shine on Earth, but in space, it shines all the time. That’s why some scientists say that, instead of putting solar panels on the ground—where passing clouds, the day-and-night cycle, and the Earth’s latitude all affect the strength of the sun’s rays—we should launch them into orbit and beam the energy back down to Earth. Solar panels in space aren’t as improbable as they sound: Solaren Corp., a California company, plans to deliver the first-ever electricity from space starting in 2016.
The idea for space-based solar power has been around since 1968, when Peter Glaser, a solar energy pioneer, ﬁrst proposed it. According to Space Canada, a non-profit group that formed in 2008 to promote space-based solar power, solar panels in orbit around Earth could absorb 10 times as much energy as the ones on the ground. The sun’s rays would be converted into a focused microwave or laser beam, and zapped down to receiving stations here. In Canada, we only get so much sunlight to use as solar power, says George Dietrich, president of Space Canada; other energy sources, like nuclear power or hydrocarbons, “have long-term difficulties.” With concerns about global warming—and our growing demand for energy—space-based solar power is an increasingly attractive option, and Space Canada insists it could more than meet our needs.
But many hurdles remain, including what technology historian Jonathan Coopersmith calls “the giggle factor” of launching solar factories into space. Convincing the public that beaming a microwave at Earth is safe—the “Death Star factor,” he says—could be a challenge, too. But John C. Mankins, a former NASA executive and expert in space-based solar power, says the technology exists. In 2008, he led a team that captured solar energy from a Maui mountaintop and zapped it almost 150 km to Hawaii’s main island, proof it could be done. (Data travels to Earth from communications and direct broadcast television satellites in a similar fashion, Mankins notes.) “We don’t want the beam to be too intense, for safety reasons,” he says, adding that it would be “a fraction of the intensity of noontime sunlight.”
According to Cal Boerman, vice-president of electricity sales and delivery at Solaren, the beam—which is about two miles wide—would have a heating effect on humans or animals, like being out on a hot sunny day, minus the sunburn. “Airplanes can fly through it. Birds will be able to transit it,” he says. “It’s not like a death ray.” (The beam will travel down to a fenced-in receiving station, where it will be converted to electricity; workers carrying out tasks inside the beam would be shielded from it, Boerman says.)
But the biggest challenge, says Coopersmith, a professor at Texas A&M University, is cost. Today, space launches cost roughly $20,000 per kilogram, he says. To send up a solar-power satellite, which might weigh 3,000 tonnes, could cost $60 billion. But Solaren says its design is lightweight enough to work. The company recently signed a contract to sell California utility Pacific Gas & Electric 1,700 gigawatt hours per year, for 15 years, from a space-based solar array. That’s enough to power “thousands of homes,” Boerman says. As far as the cost, “our first plant will take four launches of the biggest rockets in the world,” he says. “It’s not lightweight by any means. But it’s affordable.”
Others are working toward it, too. Japan, a country with few energy resources of its own, announced plans to install a one gigawatt system—roughly equivalent of a medium-sized nuclear power plant—in geostationary orbit by the year 2030, and has already hired companies and researchers to make it happen. In the wake of the Louisiana oil spill, astronaut Buzz Aldrin was also talking it up. “The timing of the oil catastrophe,” he recently said, “is a great opportunity for re-evaluating solar energy from space.”