Space-Based Solar Power

a public discussion sponsored by the Space Frontier Foundation

Making the Business Case for Space Solar Power

Posted by Coyote on July 8, 2007

People tend to use the cheapest forms of energy. Companies tend to promote whatever has the highest profit margin. Today’s petroleum infrastructure is massive, expensive, well-integrated across the international community and still highly profitable.

So…how do we make the business case for space-based solar power?

We need to keep in mind the sage advice of Machiavelli:

One should keep in mind that there is nothing more difficult to execute, nor more dubious of success than to introduce a new system of things; for he who introduces it has all those who profit fro the old system as his enemies, and he has only lukewarm allies in all those who might profit the new system.


22 Responses to “Making the Business Case for Space Solar Power”

  1. In California they are putting in an 80 megawatt terrestrial solar power system.


  2. Wow that quote Coyote is incredibly apt.

  3. Brian Wang said

    I had posted what I thought were key elements of a business case

    cheapest launch per kg ($2222 to LEO, DNEPR rocket) and per launch overall ($10 million)

    Either most KW per kg (CP1/a-Si:H thin film) or use kapton aluminum reflectors onto Spectrolab cells (40% conversion)

    Use light and cheap deployment. inflatable booms. 400 square meters, 20kg.

    Put up to 2 to 21 MW for $100M-600M.
    Maybe put up only the cheapest system $20-30million. $10 million for the launch and $20 million for the cheapest shoestring program. Whatever power level comes out is what is used. Would have to use either very cheap thin film solar (not CP1) or use cheaper solar concentrator.

    Market: sell to other space satellites and stations. $600 million for 250kw for ISS. Satellites in space now $70 billion and A few billion for power supplies.

    competition: Power beamed up from earth.

    Sign up customers first. Possibly spend a million to prove out and refine the designs to provide confidence in potential customers that it will work.

    After putting up a few Megawatts and getting a significant part of supplying and augmenting power to existing and new satellites, should start getting more applications designed for this space power approach. Find ways to build infrastructure and lower costs further.

    Identify other markets willing to pay a lot for power where flexible space based power would have an advantage.

    Expand from these niche power markets.

  4. The way to get the people to support space solar power is by demonizing the existing business infrastructure.

    In either case, I believe that the economics of the commercial situation call for in situ resources, stuff from the Moon, ala Gerry O’Neill. Moreover, I see much more benefit from space infrastructure than merely clean power. This includes better geodesy, better physics, cheaper space exploration, better stewardship of the Earth, and, most importantly, survival of the species. We already feel the effects of enclosure in mortal disagreements about nothing, and something, like natural resources. We need to ask ourselves who benefits by all that chaos, remembering that no one believes a true thing unless their heart believes it first. So this is an emotional issue as well as a technical and economic one.

    Space solar power should be seen as part of an organizing principle rather than as a project. That principle:

    The world needs an exit.
    The only way out is up.

  5. Laurence

    I do agree with this, however, it is going to take presidential level leadership to make it happen. We have to do something in the meantime.

  6. It does not appear foreordained that presidential leadership is needed, or even desired. There’s a great danger of of pursuing a dead-end technology path when high-level requirements are set by someone who doesn’t understand the technical unknowns.In the case of space solar power this really means just about everyone. We saw a dead end space program in Apollo, and ISS and now VSE. In each case, the government wasted billions of dollars because high level requirements were set to satisfy political goals and not economic realities.

    Should the material for power satellites come from the Moon? What energy conversion devices should they incorporate? The answer should be measured in amortized dollars per kilowatt hour, however, no one has good data. Especially not anyone is likely to be president.

    It would be nice to have a demonstration project but presidential leadership is probably not necessary for that. The primary value of the demonstration would be to show energy transmission feasibility and to create the prerequisites for enabling legislation, the way that SpaceShipOne spurred the passage of the Commercial Space Launch Amendments Act in 2004.

    The one thing we can agree on is that much cheaper launch is needed. Cheap launch using conventional rockets is impossible according to conventional wisdom. This conventional wisdom informs everyone who is likely to be president anytime soon. It does not seem likely that any candidate will advocate a(perceived high risk) program for cheap launch to enable an (even riskier) power satellite program. Demonstrated cheap launch would change that equation.

    Many of the technologies needed for power satellites are also needed for communications platforms or for Earth observation, so it seems to me that it might be best to allow the commercial world to develop some of the relevant technologies for their own profit making purposes. There is a clear need for exploration of the non terrestrial materials option and it appears that some of that funding may have to come from the government.

  7. There is an historical trend for electricity to displace all other forms of energy for the end user. Since space solar power is high-quality electrical energy, it should benefit from this trend. Peter Huber of the Manhattan Institute has discussed this at length in articles and in his most recent book, “The Bottomless Well”.

    Speaking of books, anyone interested in this discussion should read “The Next 200 Years” by Herman Kahn and the staff of the Hudson Institute. It has an extensive discussion of the role of space in the (future) terrestrial economy. Because it was written thirty years ago, you can check the book’s predictions for accuracy so far.

  8. Robert Jacobson said

    I would like to see all of our current energy options (nuclear, coil, natural gas, wind, solar, etc) priced out per when you strip all of the subsidies.

  9. Brian Wang said

    The link I provided (click my name on this comment)

    has an article that compares prices for energy. Note: there is a variance because raw materials and location and interest rates have an impact on costs and pricing.

    In the order in which this stuff is being built from now to 2020.
    Coal is 3.5 to 4.4 cents(US)/kwh (50-65% of the new power)
    Natural gas is 3.8 to 5.9 cents(US)/kwh (10-20% of the new power, but dropping off over the next few years)
    Hydro in China (where most of the new stuff is being built) is 1.9 cents per kWh
    (5% of new power over the next 12 years)
    Nuclear is 2.5 to 4.1 cents (US)/kwh (2-3%)
    Wind is 2.5 to 3.5 cents per kwh (2-3%)
    Concentrated solar power is 9¢–12¢ per kilowatt-hour (both solar together about 1%)
    Solar PV is 15 cents to 31 cents per kwh
    Biomass and biofuels for transportation mostly

    IEA calls for 20 trillion investment in energy infrastructure from 2005-2030

  10. oldfart53 said

    I have little experience in communicating by computer, hence my username of Oldfart. What is so attractive about SPS is that the technology exists today to build the satellites. The problem is the cost to orbit. Years ago, I heard of a variation of Solar Power Satellite (SPS) in low orbit. It involved using several satellites to transfer power from the sunlit side to nightside. This had an advantage that the receiving site could be much smaller than what could be produced from Geosynchronous orbit. This allowed the receiving sites to be placed closer to their market and in smaller increments than a Geosynchronous based SPS. In examining the problem of reducing cost to orbit, the only solution I’ve found is the Momentum Exchange Tether. A tether built with today’s materials will greatly reduce the effort placed on the launch vehicle. The low orbit SPS was built on a tether and the two could easily be combined providing both a transportation network and world power grid.

  11. Coyote said


    You are right! The cost of lift to LEO and out to GEO is the prime roadblock. If we can resolve this problem I’m pretty certain that the business case would quickly close and the commercial sector would be doing space-based solar power without much help from Uncle (as my best freind’s dad used to say).


  12. Des Emery said

    Yes, Coyote, the stumbling block is not the system to collect sun energy and beam it to rectennae down here on Earth, but the work in getting the known equipment into some kind of orbit, repeatedly, and to continue to service the network after it is established. Small rockets, large rockets, shuttles, liftports, magnetic launchers, have all to be considered, as well as looking for something entirely innovative, which, if we knew what it was, would obviate the necessity of looking at all the other alternatives.

  13. G. Vincent said

    Jumping into the discussion mid-stream, this was the topic of Dr. Gerard O’Neill’s 1977 book, The High Frontier (ISBN 9781896522678). Granted Dr. O’Neill expanded the discussion to colonization of space, but only as a means to support space manufacturing of solar power satellites. He discussed launch costs, power transmission efficiencies, overall cost, amortized cost over the project, construction logistics, and the political, environmental, and policy effects of a project of this nature. Moreover, he limited the discussion to how the concept could be pursued with current technology within the realm of reason, and not speculating on future breakthroughs. The book was published in 1977 but is even more relevant today. This concept needs revisiting, but not a complete redesign of the wheel. I would highly urge you to explore this book.

  14. keithy said

    How many square kilometres of Solar Thermal, for example, would it take to power Australia with electricity?

    Some websites would have you believe that 50 is the answer, but is it?

    It is never in the paper and people lose faith because they can’t get any facts and figures from anywhere reliable.

    This, I would say, is one of the bigggest challenges: How to get the masses to believe in it’s viabillity and so give it support.

  15. Chris said

    Space Solar Power could transmit power to anywhere in the world instantly. No other power transmission system could make this claim. I am not sure if anyone has studied this concept, but the strategic advantage is clear.

    Is this a potential solution for instant delivery of power during a disasters?

    Moving power receiving stations probably makes them more difficult for an opposing force to neutralize the site.

    A mobile power receiving station simplifies setting up a station at the south pole.

    This is a great way to deliver power to a moon base or station on Mars.

  16. Coyote – the Machiavelli quote is very apropos. I don’t know how much the political factors – those who have intrinsic reason to oppose the project – has been a factor in the wavering support for space power research and development up to now, but it will surely be a major issue going forward.

    That’s why I’m a little concerned about your “crawl first” approach – the smaller the space solar power project is, the easier it becomes for entrenched interests to kill it. We somehow have to either neutralize those who would naturally oppose it (and they have about a trillion dollars of annual revenue to play with, so I can’t imagine that could be easy) or somehow create a substantial enough program and groundswell that it cannot be stifled prematurely.

    The other issue that is key, which Dr. Valentine points out also, is we don’t know what the best technical solutions will be, and it’ll be impossible to tell without some experience of actually building the things. We have to create an environment where not only one can be built, but one can be built, and fail (economically at least); a second can be built learning lessons from the first, but still fail; a third and fourth and fifth and finally somebody gets it right and we can expand to hundreds of orbiting systems in short order because we know how to do it and costs are well-controlled.

    This can be done within a government program – but it *has* to be a government program that can tolerate failure on a huge scale, because we need that failure process to learn. With the recent tremendous rise of risk-aversion I don’t know if that will be possible in this country in the foreseeable future. Can you outline a program that might be able to both shield itself from entrenched opposition and tolerate billions of dollars of apparent loss before success? The challenge is much greater, I think, than it first looks.

  17. oldfart53 said

    SBSP will not be taken seriously until we see routine, low cost transportation to Low Earth Orbit. The initial transportation system can be built on a small scale. This makes it easier to fund than to kill. Once the initial transportation system is in place then it can be improved upon by using a space based component. The question of whether the SBSP satellites are launched from the Earth or the Moon will be determined by cost analysis. In launching from the Earth the cost of the satellites is limited by launch costs and will be determined by the mass production of low weight solar cells while lunar launch can use more conventional cell manufacturing techniques but relies on creating a factory town in space. Both methods have their uncertainties.

  18. Neil Cox said

    The following is a very optimistic projection of what humans may do over the next million years. If you can catch the spirit you will be eagar to get started on SBSP:
    With mistakes made in terraforming Venus, there will likely be details that still need fixing after a million years at a billion dollars per year = 1000 trillion dollars. We likely will not start, unless we are over optimistic. We can, however, start spending the money now. We can develop the sun shades for Earth to later be towed to Venus when Earth gets too cold. For best results the shades will allow the wave lengths best for algae photosynthesis to pass while blocking or reflecting most of the other wave lengths. We can genetically alter the algae for best performance in the Venus upper atmosphere. If the algae can fly, they will fix more carbon dioxide before they are scorched by heat and acid as they drop lower into the atmosphere of Venus. We can plan the first human outpost in the cloud tops of Venus. We can start the development of robots that can work on the hostile surface of present day Venus. We can develop the technology to send comets from the Oort cloud to crash into Venus. We can gather more data about the Oort cloud and Venus, so we make fewer engineering errors.
    My tentative plan is to build a snow fence that approximates the Arctic circle of Earth, but perhaps with a circumfrence as short as 3141 kilometers = diameter 1000 kilometers. With the pole shaded, Venus will have a polar down draft which will remain centered on the North pole as Venus is tited on it’s axis less than two degrees. The algae will be carried by the upper winds and be brought to the surface near the North pole as algae charcoal, later algae humas, if the shades can cool the north pole sufficiently. The first 10,000 years the algae will not burn as it will take the algae more than 10,000 years to get the atmosphere of Venus to 1% oxygen. Venus has an enourmous amount of atmosphere. The snow fence will keep the dead algae and unused fertilizer from being pushed off the polar platau by the South bound surface winds.
    More next post. Neil

  19. Neil Cox said

    In 100,000 years the platau will be miles higher than the rest of Venus which will help make the polar platau cooler. We will likely need the sun shades until our sun becomes a white dwarf in 5 or 10 billion years.
    At about 100,000 years, before the first rain reaches the surface, robots and/or genetically altered humans, will cover the entire polar platau with an impervious layer. The platau will be slightly bowl shaped because the snow fence will concentrate the dust near the edge. Now the acid rain makes a sea of wet dust on the impervious layer which will prevent the acid from escaping the platau This period will be difficult for both gentically altered humans and robots because of the strong acid rain. It will be necessary to repeat the impervous layers to keep the acid traped forever between the impervious layers. After another 10,000 years or more, all the acid in the Venus atmosphere will be sequestered between impervious layer in the great polar platau. Hopefully, the weight of the platau will not cause Venusquakes. Now fresh rain will fall on the platau and food crops can be grown. We brought lots of water to noursh the algae over the past 10,000 years. The rest of Venus is still 500 degrees c = 932 f, so we need to keep the polar down draft strong or very hot surface winds will occasionally blow into the high polar platau, causing great misery. A mile high wall can be built of material that passes the wave lengths best for photosynthesis, if the down draft is insufficient to keep out rare North bound surface winds. The Sun is always close to the horizon at the top of the polar platau, so some mirrors are likely necessary to allow photosynthesis on the surface during winter.
    So the temperature is comfortable for naked humans, we can grow crops, because we have rain, but we are still about 1/3% oxygen and 90 plus percent carbon dioxide. 1/3% oxygen is ok as that is about the same oxygen partial pressure we have on Earth if the air pressure on the Venus platau is 66 bar instead of the present 90 bar. The genetically altered humans will need a prothesis to remove carbon dioxide from their blood, as lungs cannot do that if the ambient is 90% carbon dioxide. We may need some additional alterations to tolerate 66 bar of air pressure. Venus has about the same amount of nitrogen as Earth, but the present percent is about 1%.

  20. Neil Cox said

    At about 100,000 years we can decide if we want to continue the costly algae program, or wait a billion years for the platau crops to lower the carbon dioxide to about 0.04 % The impact of comets, near the Venus equator is a signifcant risk to the colinists on the platau as misguided comet could hit the platau. A billion humans can live on an 800,000 square kilometer Venus polar platau. I have been collecting these numbers from many sources for many years. My memory is good for details but not for sources. ie The algae swarm may average ten million square kilometers perpendicular to the sun which is about 2500 watts per square meter at the top of the atmosphere of Venus. The algae may remove carbon with 4% efficiency = 100 watts per square meter. Efficiency is low as some of the light passes though the swarm of algae. Some is lost at the top of the atmosphere, some is reflcted back into space by the algae, but the swarm is bottom lighted by the reflection of photons from the Venus clouds below the swarm.
    100 watts per square meter is 100 megawatts per square kilometer times ten million square kilometers = 1000 gigawatts. Perhaps someone can calculate how long it will take to remove nearly all the carbon from the atmosphere of Venus at 100 % efficiency, using an average of 1000 gigawatts. If the time is shorter than I suggested, consider that some of the carbon will burn = revert back to carbon dioxide after the algae produce significant oxygen partial pressure. Also the ten million square kilometers of healthy algae may be very optimistic, even if we do both the North pole and the South pole. Also as the surface pressure drops Venus may out gas considerable additional carbon dioxide and other volitiles into the atmosphere. The bottom line is we won’t know how long it will take until we complete the task. We may not even have the power of ten correct. I have more details, so I will attempt to explain your objections and doubts. Neil

  21. Dan Lantz said

    Neil #18, 19 and 20:

    “Is a planetary surface the right place for an expanding technological civilization?”

  22. Edawg said

    Just a though couldnt you use SBSP on mars to extract Co2 fromt he regolith and put it into the atmosphere for terraforming purposes??


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