Making the Case For An Indo-USA Space-Based Solar Power Programme

By Bill Moore

Posted: 15 Sep 2010

I had a rude awakening this evening. What began as a casual journey into India's space programme -- the reasons will be apparent momentarily -- ended with the sobering realization that along with the sub-continent's explosive economic growth and the rise of the middle class, also comes the apparent need to flex its political muscles militarily in the form of nuclear submarines -- the first launched last year with more on order -- tactical transport aircraft jointly developed with the Russians, and even their own armada of aircraft carriers. And then there's their plan to send men to the moon by 2016.

I've been reading Peter Garretson's 2009 research paper for Indian Defense Studies and Analysis entitled, "Sky's No Limit: Space-based Solar Power, The Next Major Step in the Indo-US Strategic Partnership?" It is a heavily footnoted document of some 174 pages and six appendices. In it, Garretson makes the case that the next step in the United States and India's strategic relationship should be establishment of a "big policy" programme (I'll use the British spelling) to put solar power generation systems in earth orbit. While the paper doesn't go into the technological issues, it does focus on the policy implementation barriers of such a collaboration.

Of course, as a parochial American with only a passing knowledge of Indian food -- which I love -- and Bollywood movies -- which I also find highly entertaining as long as I can keep up with the English subtitles -- I asked myself was India, in fact, technologically capable of making a meaningful contribution to such a programme? Sure, their Chandrayaan-1 moon mission was an impressive achievement, discovering evidence for water, but could they really be expected to lift millions of pounds of components into geosynchronous orbit to build hundreds, even thousands of 5 km width solar arrays?

The answer is, in fact, yes. The Indian Space Research Organization (ISRO) has a series of launch vehicles; the largest being the GSLV III, now in development, will be capable of lifting 4,500kg (10,000 lbs) of payload into geosynchronous transfer orbit, putting it on a par with competing American and French launch vehicles. Importantly, it appears they can do it rather cheaply. The Chandrayaan-1 mission in 2008 cost just US$79 million.

And why should India or the United States even consider such an initiative, either alone or in partnership? Besides the fact that the Japanese are spending money on their own SBSP program and plan to have a 1 GW platform in orbit by 2030, you mean? Garretson takes pains to explain that it may, in fact, be the only choice the planet has to provide humanity with the clean, pollution-free, electric power it needs, especially in populous nations like India where 50-60% of it citizens will be living in cities by 2039. At present, India, as well as the United States, depends on coal-fired power plants for half of its electricl power generation capacity. It is estimated India's coal reserves will last 80 years, but Garretson points out that at a projected growth rate of just 5 percent a year, those reserves will be exhausted in 45 years; and this doesn't even address the critical problem of water shortages in India, water on which thermoelectric power plants, both fossil fuel and nuclear, are dependent.

So, why not simply build vast solar farms in India's Thar Desert, which stretches across the northwestern states of Rajasthan and Gujara, and occupies more than 2.5 million square kilometers? Efficiency and intermittency are why. All earth-bound solar installations suffer from the same problem: the sun shines on them only part of the day and the atmosphere -- and its associated weather -- reduce their efficiency even further. Space-based solar stations can provide solar power, transmitted back to earth in the form of low-frequency radio waves, 24 hours a day at the sun's maximum power rate of 1330+ watts per meter. At least that's the theory. Those same radio waves have to penetrate the atmosphere and its weather, be converted by circular farms of specially-designed rectenna's with 80 percent-plus efficiency back to electric power and then distributed to urban centers. In a footnote(14) on page 23 of Garretson's paper, it is estimated that only two percent of the energy transmitted down to earth would be lost in the form of heat, and that the type of radio wave being considered will have no or virtually no impact on humans or animals. He notes that, "NASA, DOE, and EPA have conducted extensive experiments to assess if there were ill effects to biological life or the upper atmosphere due to such beams. None of the studies conducted so far suggest that there is any significant detrimental effect."

Assuming all other objections and technical issues can be resolved, what's the potential of SBSP and what's its cost? Citing studies by James Snead and Harry Stine (footnote 10, page 22) Garretson estimates, "the exploitable energy in orbit exceeds not just the electrical demand of the planet today, but the total energy needs of a fully developed planet with over 10 billion people." As for the question of cost, Sky's No Limit estimates that the world currently spends $6 trillion on energy of all forms annually. Most of that energy produces highly undesirably pollution and climate change, which SBSP would not. Further, SBSP would make no environmental demands on the planet's freshwater supply.

The idea would certainly seem to have merit. Imagine an EV world where all our motor vehicles are powered by electricity transmitted from thousands of orbiting solar stations. However, moving such a project from the dreamer's stage to the schemer's stage will prove the first major obstacle to overcome. If nothing else, Sky's No Limit makes thought-provoking reading. It certainly opened my eyes to the state of technological development taking place in India beyond Tata Nanos, Revas and Hero electric bicycles.

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