It’s straight out of a Bond villain’s fantasy: an orbiting satellite outfitted with solar panels converts the sun’s energy into a microwave or laser beam that sizzles through thousands of miles of space and strikes a ground target. But instead of wreaking destruction to promote the goals of an evil genius, this energy is converted into electricity to power thousands of homes.

Clean, efficient and available 24-7, space-based solar power is the Holy Grail of renewable energy to a dedicated cadre of scientists. By 2035, oil giant ExxonMobil estimates the world will demand 35 percent more energy per year than it did in 2005. This energy will need to come from power sources other than the carbon-intensive fuels that have powered societies since the industrial revolution.

Space solar proponents claim that our current renewable technologies can’t be scaled up fast enough to meet the anticipated demand. As such, space is the answer.

“The truth is we don’t have anything else,” said Martin Hoffert, an emeritus professor of physics at New York University. “We need to go through a revolutionary transformation away from fossil fuels.”

David Criswell, the director of the Institute for Space Systems Operations at the University of Houston, who proposes a system of moon-based solar arrays that would bounce energy off satellites then down to Earth, is more direct about our need for space: “I simply do not see any other reasonable options.”

But space-based solar still requires enormous technical breakthroughs and billions in up-front capital. Will it remain the pet project of space agencies and buccaneering entrepreneurs or will the coming years bring a breakthrough?

‘The Science Is Done’

Space-based solar was first proposed by aerospace engineer and consultant Dr. Peter Glaser in 1968 and the basic outlines of the plan have remained largely unchanged since then.

Here’s the theory behind it: The sun is roughly seven times more intense in space than on the Earth’s surface and shines constantly, which eliminates the problems of cloud cover, precipitation and night that create “intermittency” problems for ground-based arrays.  A satellite roughly 36,000 km (about 22,000 miles) above the earth – called “geostationary orbit” because it appears from the ground to be fixed – can collect the sun’s energy using a large solar array and then send a beam to a “rectenna,” or ground-based antenna. The energy would then be converted into electricity.

It’s not an unheard-of idea: Government and private industry have been doing something similar for decades with communications satellites.

“The science of space-based solar power is done. We know how to do it,” said U.S. Air Force Colonel M.V. “Coyote” Smith, who is one of the military’s leading authorities on the idea. “The question is, can we do it commercially at an affordable price?”

Smith directed a 2007 study for the National Security Space Office (it is now known as the Department of Defense Executive Agent for Space), which concluded that the U.S. government should facilitate the creation of space-based solar power and become an early tester of the technology.

Smith concedes that space-based power requires researchers to make progress on technological challenges that have not yielded in decades. The cost of lifting thousands of kilograms of equipment into orbit makes space solar almost prohibitively expensive right off the bat. In 2008, it cost about $21,000 to launch a kilogram of payload into space, though the price has dropped steadily and space solar enthusiasts point to innovations by space entrepreneurs like Elon Musk and Richard Branson as evidence that prices will drop.

There are two competing methods of transmitting power, each with drawbacks. Microwave transmission requires a rectenna several miles in diameter because the beam spreads out by defraction. Lasers can focus the energy much more narrowly but the operation would require an extremely large and powerful device to achieve the necessary energy intensity.

Public Scrutiny

Whatever the means of transmission, critics argue that an energy-rich beam from outer space would be subject to endless conspiracy theories and withering scrutiny – despite a 2009 NASA study that concluded microwaves from space would be slightly less intense than the sun’s rays and would pose no danger to people.

“I have great confidence that the public will have a problem with it,” said Dr. Joseph Romm, a senior fellow at the Center for American Progress and writer of the popular Climate Progress blog. “People have a problem with noise from wind turbines and carbon dioxide bubbling up from carbon capture and storage near their homes.”

Moreover, Romm said, space-based solar is only useful if competing forms of energy, like earth-based solar, do not progress in the coming years. But most renewables have been making huge leaps. He noted that photovoltaic solar power could get down to 15 cents per kilowatt hour by the middle of this decade (coal costs about 5 cents per kilowatt hour, though this figure does not account for its environmental effects) and concentrated solar power, which uses large mirrors to concentrate sunshine to heat liquid, can store the sun’s energy overnight. To Romm, too many things have to go right for space-based solar to have a future.

Then there are the startup costs. David Criswell’s plan to manufacture solar panels on the moon, beam the power to a satellite and, finally, to Earth is technically feasible but widely considered to be outside the realm of the possible – not least because it carries a half-trillion dollar pricetag. Colonel Smith also notes that winning approval to beam energy from regulators who control the airwaves, such as the Federal Communications Commission, could present greater challenges than the technical issues.

The United States government has shown little sustained interest in space-based solar. “It’s not in anyone’s job description, nor is it in anybody’s budget path,” Smith said. A spokeswoman from the Department of Energy said the department has no space-based solar program.

Enthusiasm Overseas and in California

Still, in recent years, there has been a steady stream of announcements from private companies and international space agencies seeking to be the first to master space solar. JAXA, the Japan Aerospace Exploration Agency, announced its program in 2008 and Astrium, the space-exploration subsidiary of the European Aeronautics and Space Exploration Company (EADS) followed in 2010.

A JAXA representative said researchers are currently working on parallel programs to use both ground-based microwaves and, separately, lasers to transmit 1 kilowatt of power within the next four years. They hope to have a demonstration program in orbit within eight years. The agency is aiming for a price of 10 cents per kilowatt hour when the technology is commercialized. Astrium did not respond to questions about the progress of its programs.

The giant California utility company Pacific Gas & Electric notably contracted with solar startup Solaren Corp. in 2009 to deliver 200 megawatts of power from space by 2016. The power would be beamed from space via microwave to an enormous rectenna in Fresno County. But Solaren has released few details of its plans, leading some to wonder about its viability. Cal Boerman, the company’s vice president for electricity sales, said the company is working through the necessary approvals and lining up investors. He estimated the startup costs are in “the billions.”

The bold announcements about space solar are generally followed by silence from the companies, prompting questions about whether the programs are publicity stunts . Hoffert took particular exception to Solaren’s plans, claiming on Romm’s Climate Progress blog in 2009 that the company could not possibly reach its goals and the plan’s inevitable failure would “be a major setback for space solar power.”

His opinion today remains unchanged: “I just don’t take them seriously,” he said of Solaren. He believes that Astrium’s research into high-powered lasers is more promising.

Supporters believe the key to establishing the credibility of the concept is simple: Do a demonstration. In 2009, Hoffert and his son, who run a private space-based solar company called Versatility Energy, pitched the Department of Energy on a three-phase plan, which would culminate in beaming power to earth from a laser on the International Space Station. His idea was rejected. Several teams of private and government researchers are working on beaming energy between two points on earth and at least one group has succeeded, though with only with small amounts of energy.

Hoffert argues that government leaders today lack the ambition that drove the space race.

“In the 1960s there was a very positive view of the future,” he said. “Now, I think most people believe that future is going to be apocalyptic.”

A successful demonstration of space-based solar could be the jolt that people need to get them excited about the future again.

Top image: An artist’s rendering of a solar panel-equipped satellite. Courtesy ©Mafic Studios, Inc.