Is Space-Based Solar Power realistic?

From: http://americansecurityproject.org/blog/2012/is-space-based-solar-power-realistic/
Is Space-Based Solar Power realistic?

posted by Nicholas Cunningham on August 9, 2012 at 10:44 am

The solar industry is making great strides in bringing down costs. As manufacturing capacity has ramped up in the past few years, scale has produced efficiency gains, bringing down prices for consumers.
However, there is one critical problem with solar – the sun is not always shining. This means that the capacity factor – the amount of time that the solar panel is producing energy relative to the total theoretical amount according to its nameplate capacity – only reaches about 20%. While energy storage could smooth out fluctuations, the variability remains a problem.
An interesting article in Strategic Studies Quarterly by Peter Garretson, Lt.Col., USAF, explores one possible route around the pesky problem of the sun not shining all the time – space-based solar power (SBSP).  Under this approach, huge arrays of solar panels would be put into space, and “beam” the energy down to earth. The panels would be bombarded by solar energy without interruption (there is no nighttime in space), and the solar radiation would be 36% stronger to boot. That energy could then provide solar energy 24 hours a day on Earth.
The solar “satellites” could also serve markets that span vast distances. For instance, Garretson says, “a single satellite south of Baja California could service markets across most of North and South America; a satellite over the Indian Ocean could service markets as far apart as Africa and Indonesia, and from Diego Garcia to as far north as Russia.” This is SBSP’s ‘killer app’: it can provide on-demand energy to anywhere in the world. There are obvious military applications for this – imagine forward-deployed bases that did not require resupply routes because they were powered by energy beamed down from space.
Despite the promise, at first blush SBSP would appear to be an unimaginable engineering feat. Indeed it sounds like science-fiction. A “multi-gigawatt” solar system would need to be several kilometers in surface area, requiring hundreds of space launches to get the material into space. To put that into context, the U.S. only launched only 18 rockets into space last year.
Garretson acknowledges the criticism, pointing to the fact that critics say solar has yet to become competitive on Earth, so how could installing thousands of solar panels in space come remotely close to being cost-effective?
Garretson asserts that SBSP could also meet several strategic objectives already laid out by the United States. For example, building SBSP would necessarily mean the U.S. would have to make significant leaps in space-related technologies. Also, building a solar industry in space would also provide the U.S. with the opportunity to strengthen stability in space, provide commercial opportunities, and train a generation of scientists and engineers.
Ultimately, whether or not we pursue space-based solar power comes down to the criticism that Garretson believes is most convincing. That is the question of opportunity costs. Using scarce resources on SBSP means that less is available for other important areas, like education, national defense, or healthcare. More directly, SBSP will be competing with other energy technologies, and since SBSP’s time horizon is decades away, it will be difficult to justify large-scale investments.
ASP has explored SBSP in the past. Last November, ASP hosted John Mankins, President of Artemis Innovation Management Solutions LLC, who gave a presentation on the importance of SBSP. As private companies begin lining up to take advantage of business opportunities in space exploration, SBSP could be more realistic than many believe. As ASP Senior Fellow Andrew Holland noted in a blog post last November, it is especially important for the future of SBSP that private companies get involved because cash-strapped governments will probably not foot the bill. If there is money to be made, SBSP may be best left to the private sector.
To read more about space-based solar power, check out ASP’s work on it by clicking here
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From: http://americansecurityproject.org/issues/climate-energy-and-security/energy/future-investment/space-based-solar-power/

Space Based Solar

It is estimated that a solar power station in orbit could harness five times the solar energy captured by stations on the ground

Space Based Solar Power (SBSP) uses solar panels in space (specifically in an equatorial Geosynchronous Earth Orbit) to beaming energy to earth using harmless microwaves.
The concept was first proposed by US space expert Peter Glaser in 1968. Since then, major US reports have been published in 1997 and 2007 that show the viability of SBSP. The National Space Society has a library of the reports that have been done on this issue.
It is estimated that a solar power station in orbit could harness five times the solar energy captured by stations on the ground because of atmospheric interference and the fact that satellites in GEO do not pass into night. A satellite in Geosynchronous orbit receives 5-15 times as much solar energy per year as any place on earth.
SBSP relies on three key technologies: solar photovoltaic cells to create electricity from sunlight, microwaves to beam the energy to earth, and rocket technology.
These technologies exist today: solar cells are becoming common, the technology to beam energy to earth is essentially the same as the radars in the nose of a fighter plane, and we have been launching satellites for over 50 years.

Read about the ASP-Hosted Event on SBSP in November, 2011

There are costs, and they are currently significant. The cost of launching satellites is too high to be competitive. The reason for that cost disparity is that America’s launch systems (rockets) are used so seldom that we are unable to achieve the economies of scale that would inevitably result from a greater demand for launch vehicles.
This system uses technology that already exists. PG&E, the California-based utility, has entered into a deal to purchase electricity from a startup – Solaren – that will harvest energy from space.
Japan, China, India, and Russia are taking preparing space-based solar programs. India – who has begun a significant investment into a ‘solar mission’ – has expressed interest in partnering with the United States on a SBSP program.
SBSP could be a future source of baseload power, but for now its major advantage is that it can provide energy on demand anywhere in the world. Remote power should be an obvious benefit to a military looking to power a base in a remote location.
Other potential customers would be remote energy exploration – like shale or Arctic exploration – that is far from any electric grid.
A power plant in orbit would be an important way to change our paradigm in space from the choice that NASA faces of either scientific research or human exploration.
SBSP needs start-up capital, but ultimately, this may be something that is better handled by the private sector than NASA. There is money to be made, and the company that proves it will have a significant advantage.