In principle, sunlight is a near-ideal energy source since it’s essentially free, ubiquitous, and surprisingly powerful. In practice, however, even vast arrays of the most sophisticated photovoltaic cells, which convert sunlight to electricity, seem incapable of meeting all our energy needs. This is largely because they’re confined to the ground, where the Earth’s rotation and atmosphere eliminate and attenuate sunlight.
During the heyday of the Space Age in the late 60s, researchers conceived of solutions to this problem that relied on placing solar arrays, or “powersats,” in orbit. The powersats would beam the collected power down to Earth as microwaves, which can easily penetrate the atmosphere with scarcely any energy lost. Space-based solar power (SBSP) seemed feasible, except for one thing: Launching the necessary infrastructure into high orbit would be prohibitively expensive, especially when cheaper fossil fuels were readily available.
Today, as with many other alternative energy proposals, interest in SBSP has been rejuvenated by the rising direct and indirect costs of fossil fuels, and several SBSP companies have formed. Earlier this year, Pacific Gas & Electric, a major California utility company, signed an agreement to purchase hundreds of megawatts of power from Solaren, an SBSP company, beginning in 2016. Last month, another SBSP company, PowerSat Corporation, filed two patents for technologies that the company claims can shave billions of dollars off the launch costs for an SBSP system. Seed’s Lee Billings spoke with PowerSat’s CEO, William Maness, about the company’s technology and the revival of SBSP.
Seed: How is space-based solar power different than solar power on the ground?
William Maness: Terrestrial solar power has some irksome limitations: It doesn’t work at night, it works poorly when it’s cloudy, and it’s really only cost-effective in a few places in the world. It works better in places like Phoenix than in places like Seattle. So the idea is to harvest the solar energy in high orbit where the sun shines 24/7. That constant sunlight is a big deal when you’re trying to supply power to utility companies for their customers.
Seed: What makes it superior to other forms of alternative energy?
WM: The way power is actually generated and handled in the world involves something called “dispatchable” power. Alternative energy is generally intermittent, and thus not dispatchable. Dispatchable means a utility can make a contract with someone that says, “On December 21st of 2011, I want you to carry 1,000 megawatts of my load for six hours.” So they make a financial contract, and these things are traded back and forth. This economic system behind [power generation] is the cornerstone of what keeps our lights on.
SBSP gives you a continuous source of electricity that you can lay down independent of geography. You can put a receiver in New Jersey and a receiver outside of Seattle, and you can switch the power between those from our orbital system with essentially a flip of a switch.
Seed: Ideas for SBSP have been around since the late 60s. So why is it only commercially viable now?
WM: The costs of deploying powersats are falling, and the costs of fossil fuels are rising. When powersats were first envisioned, solar cells were these huge monolithic crystalline beasts that weren’t very efficient in weight per watt. Now, we’re printing thin solar cells on sub-micron aluminum and titanium. Solar cells have gotten much more efficient per unit at converting sunlight to electricity, and the weight’s gone way down. Weight—or, really, mass—is everything in space.
Meanwhile, the base cost and the burdened cost of fossil fuel is rising fast. The base cost is just how much it costs to extract and distribute fossil fuels, pretending that carbon emissions don’t mean anything and that there’s no penalty whatsoever for warming the entire world. Burden cost is when the political system says, “Wait a minute. You can’t do that!” and spanks you in terms of taxations and carbon-curbing measures.
Seed: Are you worried about fluctuations or manipulations in the price of fossil fuels causing problems for PowerSat?
WM: There will surely be further price manipulations. You see OPEC doing it all the time. But the market can only support this in the short term. The fossil fuel price cycle is fairly regular, but the cycle’s tightening every time it occurs, getting shorter and shorter in duration. We could easily weather another artificial lowering because we know what’s coming on the other side of it. The market’s fundamental feedstock is inflexible; there’s only so much fossil fuel. Powersats, once established, will always win over the long term because there’s essentially no cost for fuel—you get it for free from the Sun.
