Space-based solar power has been studied since the 1970s but the U.S. Department of Defense is giving it a new look, according to an article at Space.com (19 September 2007).
The deployment of space platforms that capture sunlight for beaming down electrical power to Earth is under review by the Pentagon, as a way to offer global energy and security benefits – including the prospect of short-circuiting future resource wars between increasingly energy-starved nations.
A proposal is being vetted by U.S. military space strategists that 10% of the U.S. baseload of energy by 2050, perhaps sooner, could be produced by space-based solar power (SBSP). Furthermore, a demonstration of the concept is being eyed to occur within the next five to seven years.
A demo of the technology is a critical first step (to prove it can be done and to identify the remaining challenges), says the director of the SBSP study, Col. (Select) Michael “Coyote” Smith, chief of the Future Concepts Branch in the National Security Space Office. (Smith’s shop is known as the “Dream Works” of the National Security Space Office.)
Smith says he sees the Defense Department as a customer of the resulting clean energy — not as the deep-pocketed financial backer of the project.
The U.S. Department of Defense has an “absolute urgent need for energy,” Smith said, underscoring the concern that major powers around the world – not just the United States – could end up in a major war of attrition in the 21st century. “We’ve got to make sure that we alleviate the energy concerns around the globe,” he said.
Proponents of the technology are looking at this scenario:
[B]y 2050 the goal is to have forty or so concentrator-photovoltaic space-based solar power (SBSP) satellites in geostationary orbit, each broadcasting via microwave between 2-5 gigawatts of power to terrestrial electrical power grids, with 1-to-5 broadcast antennas that can beam power to as many locations.
Gigawatts! Reminds me of the great movie Back to the Future (1985), where wacky scientist Dr. Emmett Brown discovers — back in 1955 — that he needs 1.21 gigawatts to ignite his Flux Capacitor for time travel.
Brown: “1.21 gigawatts? 1.21 gigawatts? Great Scott!”
Marty McFly: “What the hell is a gigawatt?”
According to the movie, it requires either nuclear energy (via plutonium) or a bolt of lightning.
But I digress. Back to the future of solar power satellites…
On the positive side, there have been technical advances in “micro- and nano-electronics, lightweight inflatable composite structures, ultra-small power management devices, as well as laboratory demonstration of photovoltaic arrays that are close to 68% conversion efficiency.”
But, of course, there’s no shortage of challenges, such as:
- extreme complexity and scalability issues
- a cost of hundreds of billions of dollars
- the need for a long-term political commitment (i.e., budget)
- the need for technology breakthroughs, such as “wireless power beaming”
- the need to manufacture the satellites in space using lunar materials
- legal issues
- and did I mention the need to scrounge for hundreds of billions of dollars?
By the way, as one proponent acknowledged, “the microwave beams will heat the atmosphere slightly and the frequency must be chosen to avoid cooking birds.”
Personally, I put solar power satellites in the same category as the space elevator: Fascinating, ambitious, but ultimately so gigantic and expensive and fraught with complexity that it’s hard to imagine it really happening.
The Space Frontier Foundation’s discussion blog on Space Solar Power