Space-Based Solar Power

a public discussion sponsored by the Space Frontier Foundation

Russia Working on SSP: Claim ~50% Efficient Solar Cells

Posted by Coyote on August 5, 2007

“Tapping Into Space For Energy”
By Yuri Zaitsev, Novosti, August 03 2007

The Russian News and Information Agency released a story by Yuri Zaitsev (click the link above to read). Therein he nicely summarizes the need for space solar power and the evolution of photovoltaic cells that collect and convert solar power into electricity. What is most interesting is that he asserts that by using pure quartzites (citing, “The largest deposits of very pure quartzites are found in Russia, which had vast reserves of them”) that:

Recently the Joint Institute for Nuclear Research in Dubna, near Moscow, developed a photo cell with an efficiency of almost 50%. Scientists describe their product as a “star battery.” It is an example of how nanotechnology can improve the workings of well-known processes.

Keep in mind that every improvement in efficiency along the collection-delivery pathway improves the business case.

This begs two questions:
1. What are the technical implications of ~50% efficient cells?
2. Does this signal cooperation or competition with the Russians?

I was a little concerned that Zaitsev was a Kool-Aide drinker who would raise the hackles of our space cynics–who do us a great service by keeping us realistic and focused on the business case–but he ended with this:

To deliver parts to working orbits, assemble them there and later perform maintenance on the plants, assembly, aerospace and inter-orbit transports systems will have to be developed, which is just as challenging as building the plants themselves. But whatever way you look at them, solar plants in space are a better and less costly option for energy problems on the Earth than flying to the Moon to fetch helium-3 for fusion reactors.

I surmise that he sees the goal quite clearly (and optimistically), but he realizes that there are numerous infrastructure challenges that must be resolved first.

If I had a Space-Based Solar Power teeshirt, I’d send him one.

Your thoughts?


14 Responses to “Russia Working on SSP: Claim ~50% Efficient Solar Cells”

  1. Marcus Vitruvius said

    Actually, the real questions begged are:

    1) What is “almost 50%?” We already have solar collectors in the mid 40% efficiency range. Is that “almost 50%?”

    2) What about that capacitor they claim to have? The article goes on to mention that the same material somehow makes a “supercapacitor.” No physical justification is given for why gold particles on silicon makes a better capacitor.

    Said capacitor is also described as being “3 sm [sic] in diamter” (cm?) and stores 900 times the amount of power as a car battery. Well, one stores energy, not power, so we’ll assume that’s what they meant. But car batteries are rated for ampere-hours (at their implied 12V potential) in the neighborhood of about 50 or so. Doing the math, that’s 12V * 50A-hr * 3600s/hr = 2.16 MJ of energy in a car battery.

    I am therefore being asked to believe that a 3 cm(?) diameter cylinder of unspecified but presumeably somewhat small length– let’s arbitrarily assume 10 cm– is capable of storing 1944 MJ of energy, which is enough energy to bring 4000 kg of water from freezing temperature to boiling temperature.

    As an electrical engineer, I find these claim difficult to credit, not only for the amounts of energy being spoken of, but for the lack of physical justification (why would a method for improving photoelectric efficiency improve capacitance to that degree?) and the shocking imprecision of the claims.


    3) Why do we believe these claims?

  2. John Lee said

    1. What are the technical implications of ~50% efficient cells?

    From PHYSORG.COM July 24, 2007

    “Unique Quantum Effect Found in Silicon Nanocrystals
    Researchers at the U.S. Department of Energy’s National Renewable Energy Laboratory, collaborating with Innovalight, Inc., have shown that a new and important effect called Multiple Exciton Generation (MEG) occurs efficiently in silicon nanocrystals. MEG results in the formation of more than one electron per absorbed photon. Calculations at NREL by Mark Hanna and Nozik have shown that the maximum theoretical efficiency of quantum dot solar cells exhibiting optimal MEG is about 44 percent with normal unconcentrated sunlight and 68 percent with sunlight concentrated by a factor of 500 with special lenses or mirrors. Today’s conventional solar cells that produce one electron per photon have maximum efficiencies of 33 percent and 40 percent, respectively, under the same solar conditions.”

    So, 50%+ efficiencies don’t seem to be too far out of line with what we can expect in 5-10yrs when the first demo SBSP is ready to be deployed. Higher efficiencies should reduce the size by half to two thirds with the same energy collecting capacity.

    “2. Does this signal cooperation or competition with the Russians?”

    I think it signals neither cooperation or competition, but maybe it does give us an opening to following through on the International cooperation angle we have been discussing in this forum.


  3. I have no idea if this is realistic or not. However, I do remember from my years in solid state physics research that the Russians had a well-deserved reputation for excelling at crystal-growth and materials preparation. Often the best bulk samples of various kinds were prepared in Russia, and studied in labs around the world. They couldn’t so easily do the fancy micro-electronics nano-scale surface deposition stuff, but for bulk materials they were great. So if there’s a specific materials preparation technique that leads to highly efficient solar energy capture, I’d not be too surprised if the Russians got it working first.

  4. oldfart53 said

    Competition is likely to begin when the energy is exported to other countries. Solar power Satellites have a major advantage in that they cannot be nationalized like ground based solar, hydroelectric, wind, or conventional powerplants. I think it likely though that Solar Power Satellites will be developed for internal power needs first. This raises the question of when the U.S. will commit to SBPS since we have extensive coal sources. If an SBSP system is already in place will the U.S simply buy energy from it or develop our own SBSP.

  5. Des Emery said

    Hey, Coyote, heard you on radio, good show. As for international co-operation, I can
    see Russian hands held out in friendship, but Othello thought Iago was his good friend
    until… Just watch your back, please. The Russians just planted their flag on the North Pole and justified the move by citing the American flag on the moon as a similar exercise in ‘scientific endeavour.’ If they see SBSP as a benefit to them, of course they will join in, but that’s no guarantee all the Russian folks will get cheap power.

    P.S. It seems that latecomers to the site have not read or digested your early comments that this project, to you, is secondary to your primary wish to get into Space and open it up. I hope that the space elevator, not rocketry, will make that wish come true.

  6. Edawg said

    Sweet yo.If it wasnt for ITAR it would be easy to imagine Russian built Ssp arrays constructed with Japanese robotics with American launch services .But we got ITAR so sharing laptop data with E.U’s ATV and ISS = one giant expensive clusterfudge.I wonder how much China would be willing to pay for one of Bigelows habs?There needs to be a path for getting through the ITAR jungle without an army of lawyers.

  7. If you read the information that this article is based on carefully, the researchers did not develop solar cells with an efficiency approaching 50%. They demonstrated an effect, which they believe could be implemented in a material that would make a solar cell, which they believe could reach 50% efficiency. It is a very long road to make a solar cell.

  8. The figure of merit that should be of interest to SSP advocates is not efficiency, it is cost. And it is not the cost of any one component, it is the cost of the energy delivered to the end user. SSP is a system and the system design has a very wide trade space and, as of now, that trade space is poorly explored. In particular, the opportunity to use non terrestrial materials has been ignored.

  9. Bluebird said


    It’s true “SPS cannot be nationalized” (Oldfart53, 8/15)” and that the “star battery” could be an “opening to int’l cooperation,” (John Lee 8/5)with the Russians and their friends, at the very least in the interests of saving the planet from imploding due to global warming.

    In 1991, the very summer of the fall of Communism, about 30 Fellows of the Russian Academy arrived at our SPS conference in Paris willing to share research materials and with great optimism for int’l cooperation.

    How many chances do we get to treat others with respect (and not just occasional nods due to fear) and lead int’l cooperation for SBSP? It is my considered opinion this is our last.

  10. Joe Russo said

    If someone has not already, I think it is time to invite the author and people referenced in the article to join us. I believe that would be the politely correct international way to enhance the group’s goals. Also, I believe we should consider taking this group to the next level, finding people with different languages to create chapters of the group in order to gain more collaborators worldwide. This is something I proposed to a non-existent group (I rather not publicly name) at one point, but was laughed at. Now, I wonder if it was so funny, after all. If this is of interest, I have something in mind that can also result in world wide acceptance to a space policy such as I started one on my blog at Enforce Code of Universal Justice (ECUJ)

  11. natacha said


  12. Neil Cox said

    Perhaps he really ment power. A car battery is rated perhaps 600 cranking amps times 5 volts (almost shorted) = 3 kw times 900 = 2.7 megawatts. A modest capacitor will supply that much power for a few picoseconds. Perhaps his will suppy 2.7 megawatts for a few microseconds plus some moderate exaggeration. Perhaps the “disk” has a heigth of 900 centimeters?
    Quartz is used for pizio electric including frequncy stardard crystals. Is that the same thing as quartzites? Neil

  13. Idetrorce said

    very interesting, but I don’t agree with you

  14. Edawg said

    First world countries have a very narrow window of oppurtunity over the next several years to export space technology to third world nations or else they will do it themselves.Over the course of the next 2 decades every third world nation will have reached the tech point of establishing their own space programs or the basterd child of the cold war ballistic missle programs.Every third world nation with their own ballistic missle program by 2030 isnt that a scary thought?Evidence of this can be already seen by Mexican attempts to establish their own space program.Either we compete over the Artic resources worth billions or offworld resources which number in the trillions.

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