Space-Based Solar Power Comes Closer to Reality
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This concept of a solar power satellite provided by NASA shows the assembly of a microwave transmission antenna. |
The decades-long dream of harnessing the sun’s power in orbit as a source of clean, renewable energy on Earth may lie just over the horizon. Yet, unlike traditional space efforts, this concept may come to fruition as a result of commercial—not government—commitment.
Government agencies, both in the
The concept behind the space-based solar power (SBSP) programs is to place very large solar arrays into continuously and intensely sunlit Earth orbit, collect gigawatts of electrical energy and beam it to Earth. The solar energy received on the surface could be converted into manufactured synthetic hydrocarbon fuels or could be used either as base load power via direct connection to the existing electrical grid or as low-intensity broadcast power beamed directly to consumers. Satellites could deliver energy around the clock, virtually all year long, because the sun’s rays are up to 10 times stronger in space and there is no weather-related interference or loss of sunlight at night.
In the
The most recent study, done in 2007 by the Defense Department’s National Security Space Office, states that preventing resource conflicts in the face of increasing global populations and demands is a high priority. A single kilometerwide band of geosynchronous Earth orbit experiences enough solar flux in one year to nearly equal the amount of energy contained within all known recoverable conventional oil reserves on Earth today, according to the Defense Department study. That amount of power offers enormous potential for energy security, economic development, improved environmental stewardship, advancement of general space faring and overall national security for those nations that possess an SBSP capability, the Defense Department study explains.
The various government reports and recommendations have not yet led to significant action, according to industry sources. One reason policy makers elected not to pursue development is that other forms of energy were relatively less expensive; however, recent world events—including the cost of oil and the stability of oil producing nations—have changed those calculations. The Japan Aerospace Exploration Agency is one exception to government funding of SBSP. It has committed to developing the technology to provide electrical power from space in the 2030s.
The lack of government support has not stopped companies from developing SBSP technologies. “Space solar is really a no-man’s land in that the Department of Energy is interested in generating electricity, but they don’t do anything in space. The Department of Defense doesn’t generate electricity, and NASA has no funding right now,” says Cal Boerman, vice president of sales and electricity delivery for Solaren, one of the companies investing in SBSP technology. “A lot of people out there are hoping for government funding, but we have not sought government funding, and we’re not seeking it,” he adds.
Solaren was formed in 2001 by a team of space scientists and satellite engineers with extensive experience in the U.S. Air Force and with major aerospace and defense companies. The company’s goal is to deliver 200 megawatts of base load space solar power by 2016. Solaren executives believe they are the first company to receive an actual contract to provide electrical power from satellites. The company announced an agreement in 2009 with Pacific Gas and Electric (PG&E), a major utility in northern
Under the contract, the amount of which has not been disclosed, Solaren is required to provide 200 megawatts of clean, renewable power over a 15-year period. Solaren is paid only if it delivers. PG&E is not funding Solaren’s current technology development efforts. For technology development funding, Solaren executives are turning to qualified investors. The company may opt to provide an initial public stock offering once it has a satellite in orbit and is able to demonstrate that it works. Boerman concedes that finding investors in today’s economic climate is hard work, but he says the company is succeeding well enough to meet its 2016 deadline.
Solaren’s patented solution includes satellites using solar cells to convert the sun’s energy into electricity to power high-efficiency generators onboard the satellite. The generators convert the electricity into radio frequency energy and transmit it to a ground receive station, which then converts the energy into direct current electricity and uses the local power grid for transmission to the PG&E delivery point.
Some experts—even some proponents of SBSP—believe achieving such a capability will cost tens of billions of dollars and will require satellites larger than the International Space Station, too large to be launched by conventional means and possibly requiring construction by robots in space. However, Boerman contends that modern-day communications satellites already use solar panels to collect power, convert it to radio frequency energy and transmit it to Earth. Those satellites have been in use for more than four decades. Solaren will use the same basic technology and build a much larger satellite, one that might have to be constructed in pieces, launched and then docked together in space using traditional, proven docking methods.
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This NASA photo depicts the energy emanating from the sun. Companies around the world are racing to capture some of that power with orbiting satellites to provide electricity on Earth. |
EADS Astrium, a major spacecraft manufacturer headquartered in
That satellite will beam energy toward a mobile receiver 20 to 30 meters in diameter rather than to a large, fixed receiving station. The receiver will be specifically tuned to the laser’s wavelength, which will be eye-safe, and the power on the ground will be about as warm as it feels when walking in normal sunshine.
The mobile concept has commercial appeal and could be used for disaster management, but it also offers a military advantage for forces in remote areas, explains Matthew Perren, Astrium innovation manager. One drawback, he volunteers, is that the laser will not be effective on foul-weather days. “What you have to do is take a global perspective. From the satellite’s point of view, it can point anywhere, and I guarantee there will be receivers not in cloud that will need that power. It won’t be available to every receiver because of cloud cover, but from a global perspective, we are always able to provide energy to the ground.”
If the demonstration proves successful, the company will work toward its long-term vision of putting larger satellites in orbit and providing energy directly to the electrical grid. Astrium is investing its own money and is seeking partners to share the investment. “We’re not going to do this in isolation. We’re actively seeking technical partners and investment partners to push this forward. We’ve had lots of interest from around the world, and that door is still open,” Perren states.
Meanwhile, PowerSat Corporation,
PowerSat Corporation, a subsidiary of PowerSat International, which is based in
As its competitors elsewhere, Space Energy, a Swiss company, intends to launch a demonstration satellite before placing larger satellites in orbit. The demonstrator will be placed in low Earth orbit and will be designed to prove the viability of orbit-to-ground wireless power transmission and space robot assembly capabilities.
Peter Glaser, an American scientist, is widely credited with introducing the concept of SBSP generation in 1968, the same year astronauts first orbited the moon. The first significant
Since the initial investigation of this technology more than three decades ago, oil prices have jumped from $15 per barrel to about $80. In addition to global concerns over climate change,
While governments hesitate, industry experts say this is the time to move forward. “This is important stuff—green energy, limitless energy,” Perren says.
WEB RESOURCES
National Space Society: www.nss.org/settlement/ssp
National Security Space Office study: www.nss.org/settlement/ssp/library/nsso.htm