Residents of California! Prepare to open your grids to endless, plentiful electricity -- generated by solar panels in outer space and beamed down to your planetary surface. No radiation-protection required.
Come June 2016, energy from sunlight will be transformed into low-energy density microwaves. It will travel all the way from geosynchronous orbit at 22,000 miles above the Earth, through the atmosphere and clouds, to receiving antennas on the ground, and from there, into our electrical wires.
Or maybe not.
Space Based Solar Power (SBSP), a longtime staple of science fiction, could be only a few years away. Since the Pentagon released a report in 2007 suggesting that this type of power generation is a technically feasible solution to looming worldwide energy shortages, a few entrepreneurs and weathy investors in Japan, China, Russia and the United States have committed millions of dollars to its development. Advocates like Ralph Nansen and Feng Hsu (Space Energy), John Mankins (Artemis Innovation), and Charles Radley (JPL Space Foundation) think SBSP will generate an entirely new industry, create thousands of new jobs, revitalize the world economy and point us towards a solution for the global shortage of renewable energy.
Supporters tout the benefits of SBSP as a potential source of baseload, or "always on" power that is available 24-7. They claim that it is superior to the intermittent current produced by wind turbines or solar plants on Earth, two of the most promising up-and-coming forms of renewable energy.
SBSP advocates point out that electric power generated at the "utility scale," that is, in large power plants that transmit current over long distances, cannot be easily or cheaply stored using current battery technology. The power goes to waste if it isn't used right away. Therefore, utilities depend largely on plants which use coal ("coal-fired") or natural gas ("natural-gas fired") as a source of baseload electricity. They can easily obtain extra coal and natural gas, and store it for use during periods of peak demand, when a lot of people are using a lot of current. No form of renewable energy, with the exception of hydroelectric power and, perhaps, wind energy in some parts of the world, can currently compete with fossil fuels as a source of baseload electricity. They can feed energy into the electrical grid, but not in a predictable, reliable way. Solar panels, in particular, have a built-in inefficiency because they capture energy only when it's sunny, not at night-time or on cloudy days, and they need to be erected over a large land area in order to collect enough energy for use in power plants.
Advocates also assure us that space-based solar power is safe for humans. The microwaves generated by SBSP satellites would be a low-energy form of electromagnetic radiation, made of the same stuff -- traveling photons of light -- as the radio waves that transmit signals from communications satellites. They would move easily from space through earth's atmosphere and clouds without getting scattered, and they wouldn't hurt humans, partly because their frequencies would be lower than that of infrared light and partly because they would be more spread out than the beams that cook food inside a microwave oven. The receiving antennas would be installed over a two square mile area.
Solaren Corporation, a Manhattan Beach startup, appears to be way out in front in the race to commercialize SBSP. In April 2009, PG&E, a leading California utility, signed a 15-year Power Purchase Agreement with Solaren to supply 200 MW of power a year beginning on June 1, 2016. The California Public Utilities Commission approved the contract in December 2009, and by May 2010 the CEC (California Energy Commission) had pre-certified a planned Solaren receiving facility in Cantus Creek, CA under the state's Renewable Portfolio Standard.
Solaren is the first private firm in the world to attempt the commercial production of solar power in space. Other firms such as Space Energy, Space Island Group, and USEF, a Japanese consortium, are also pursuing SBSP but they are not as far along in fundraising or prototype design.
This summer, Solaren plans to begin ground testing for its project, now nearly 10 years in the making, to launch free-flying arrays of "power satellites" into geostationary earth orbit (GEO). If all goes as planned, the free-flying satellites will generate solar energy as they orbit the Earth, convert it first to electricity and then to microwaves, then transmit the microwaves 22,000 miles to receiving antennas on Earth which will convert the microwaves back into current and feed it into the electricity grid.
For the company's supporters, the PG&E contract and the regulatory approval from two state agencies in California are evidence that SBSP, as envisioned by Solaren, makes economic and technical sense. According to researcher and space advocate Al Globus, who sits on the board of the National Space Society:
"The big elements, solar collection and final power transmission, are thin film and weigh very little. The solar collection is done by a mirror, probably with no more than a few g/m2 for the material. They solved the antenna size problem elegantly -- the transmitter is small and directed at a large mirror, also thin film, so the Earth antenna sees a large thing. Looks hard to do, but I don't see anything impossible."
According to aerospace expert Charles Radley, CEO of the Stratowave Corporation, and a supporter of space-based solar power,
"It all depends on the parameters of the system they are proposing. The devil is in the details.... For $1 billion I doubt [they can] build a full scale operation system. But it is adequate to build some small scale demonstrators, and to retire most of the technical risks."
Solaren's CEO, Gary Spirnak, exuded confidence in a series of phone interviews and seemed unperturbed by the many unknowns of the project.
Startup capital? No problem. "We're on track to raise $1 billion in the next two to three years," he told me, "and we'll become a major customer for US aerospace firms."
Technical hurdles? Easily overcome. "We're not building anything new, we're just building very big."
Fast-moving timeline? No worries -- the signed contract with PG&E would light a fire behind Solaren and its suppliers and keep them honest. "We have a signed contract. There are consequences for us if we don't deliver the energy we promised by the date we agreed on." If Solaren didn't have suppliers lined up, or a realistic timeline for producing the equipment it needs to send into space, why would it have taken on the risk of a binding contractual agreement?
Even so, critics of the Solaren scheme are numerous and vocal. They call SBSP a pipe dream, a "NASA fantasy," and a "con." Shubber Ali, a management consultant who has worked extensively with the space industry and founded the "Space Cynic" blog, said in a phone interview "There's a new sucker born every day... and lots of high net worth investors in the space industry are suckers." According to Georgia Tech physicist Darel Preble, chair of the Space Solar Power Workshop, it is "highly unlikely that Solaren can overcome [technical and fundraising] difficulties in the timeframe they are committed to, using their stated, patented, satellite design features."
Renewable energy analyst and investor Chris Nelder dismissed Solaren's project as "pure fantasy" in a blog post on April 15 2009, and wrote to me last week that his views have not changed. In the original post, he pointed out that space-based solar power will likely lose in a competition with other forms of renewable baseload power that are gradually coming online:
Concentrating solar power (CSP) plants... are utility-scale systems that can run 24 hours a day with internal heat-storage technology. These plants generate power for $3,000 to $3,500 per kilowatt and likewise use current, commercially available technology... At 11 to 12 cents per kilowatt-hour (kWh) of production today, on its way to 7 cents per kWh for next generation plants, CSP systems will soon be economically competitive with coal-fired and nuclear electrical generation. Why would anyone be interested in space-based solar power when commercial utility scale solar technology on the ground today costs 0.3% of its price?
Nelde and Ali both point out that PG&E has taken on no risks by signing the agreement with Solaren; they view it as a public relations maneuver to foster good will and to show that the utility is attempting to meet its mandate to purchase 30% of its energy from renewable sources by 2020.
SBSP raises ferocious passions among both its supporters and its opponents. What's the reality? What are we to make of this promising, evanescent technology that's been on the drawing boards for decades but has never yet been tested in space?
There's no question that the implementation of SBSP will be fiendishly complicated, if and when it actually happens. Consider all the factors that need to be taken into account for the project to work. The firm that successfully takes it on must
1. Raise billions of dollars from angel investors to design, test and build a prototype,
2. Obtain national and international permits, ...
3. Work with suppliers to design and manufacture equipment at a scale that's never yet been attempted,
a. Solid State amplifier for sandwich-- Triquint?
b. Rectenna -- Power Beam?
c. Solar Cells -- Spectrolab?
4. Contract with an aerospace firm to launch tens of thousands of tons of equipment into geosynchronous orbit,
5. Align the equipment at the right position in GEO so that it can beam the energy to a precise location on Earth.
Only after all five milestones have been met can the project begin to do some real work, namely:
6. Collect sunlight in GEO and transform it to electricity
7. Transform the electricity to microwaves
8. Transmit the microwaves to Earth
9. Rectify the microwaves into AC electricity
10. Route the electricity into the electrical grid
11. Sell the power to a utility, and
12. Continue to maintain the satellites from the ground to ensure that the entire process can continue.
The crux of the argument against Solaren is around its timeline and projected costs for this process, which promises to be long, complex and very expensive.
According to critics, it will be so expensive and technically difficult to launch a fully functional 1000-MW solar plant into geostationary orbit that either the company will go bankrupt trying to honor its contract, or it will succeed in delivering renewable energy much later, and at a much higher cost, than competing earth-based methods, such as concentrating solar power, geothermal, wave energy or wind farms.
Now, consider some current events that could affect the implementation of SBSP:
(a) the continued failure of BP and the US government to stanch a deep water oil spill in the Gulf of Mexico,
(b) the June 4 launch of the Falcon 9 rocket at Cape Canaveral, and
(c) the failure of Atlas 15, a communications satellite in geostationary orbit, in mid April 2010. The Atlas 15 continues to send and receive electromagnetic signals, but it stopped responding to commands from Earth in mid April, 2010, and is now drifting aimlessly through orbit.
Space Solar Power has been in the news before, notably about a year ago when Solaren first signed a contract with PG&E. However, the coverage has varied from breathless excitement to cynical dismissal, with a tendency among many writers to skirt over the technical and financial details that will make or break SBSP. The information out there is plentiful, but confusing, while with some exceptions, the general reader summaries tend towards the flippant.
As far as I can tell from my research so far, it is not clear to any one, either in favor or against the technology, whether a watertight business case can be made for SBSP as an alternative to existing sources of renewable energy. Nobody's actually tried it, so we don't know. There are strong opinions on the topic, among experts and non-experts, but I have not found any articles in the general interest news publications, either in print or online, that make a convincing case either way.