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Harvard Business Review and Yale e360 hype space solar. Why?

By Joe Romm on September 3, 2009 at 1:00 pm

"Harvard Business Review and Yale e360 hype space solar. Why?"


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Harvard Business Review touts space solar in its September piece, “On the Horizon: Six Sources of Limitless Energy?” (subs. req’d)  Of course, they also tout nuclear fusion as one of the six (see HBR figure above), so perhaps that tells you their time horizon is … 50 years from now (or maybe never), long after the climate is destroyed.

More puzzling is Yale e360, which has a long piece on space solar, with the hype “Now, a host of technological advances, coupled with interest from the U.S. military, may be bringing that vision close to reality.” Aside from discussing the military’s interest, which may not be totally benign and in any case is largely irrelevant to the question of commercial viability, the piece discusses the deal Solaren Corporation has with Pacific Gas & Electric (PG&E) “to provide 200 megawatts of power “” about half the output of an average coal-fired power plant “” by 2016 by launching solar arrays into space.”

As I blogged here, the physicist Marty Hoffert sent an email to the media in the spring on this (which I reprint in full below) that begins:

The PG&E deal is a scam. Pure and simple. We don’t need to study it in detail any more than one needed to study Bernie Madoff’s investment scams.

Since space solar is getting hyped again, let me start with my original discussion (here).

Not many people I know think space solar is a low-cost, scalable solution.

Space Solar disk.jpgCertainly it is worth pursuing any genuine low-carbon baseload power source if it can be practical and scalable — and affordable, which I would put at $0.15 a kilowatt hour or less for. The problem with space solar is that, like hydrogen fuel cell cars, there is little chance it could be affordable until it is massively scaled up — and no guarantee that it would be practical and affordable even then. That’s one reason major utilities have been unwilling to take the risk on it.

Until now.

Apparently at least one serious utility that has invested in “wind, geothermal, biomass, wave and tidal, and at least a half dozen types of solar thermal and photovoltaic power” is looking in to it. Jonathan Marshall, Chief, External Communications, Pacific Gas and Electric Co., sends me a link to his posting on NEXT100.com, “a blog supported by PG&E that explores the intersection of the clean energy business and the environment”:

PG&E is seeking approval from state regulators for a power purchase agreement with Solaren Corp., a Southern California company that has contracted to deliver 200 megawatts of clean, renewable power over a 15 year period.

Solaren says it plans to generate the power using solar panels in earth orbit, then convert it to radio frequency energy for transmission to a receiving station in Fresno County. From there, the energy will be converted to electricity and fed into PG&E’s power grid. (See interview with Solaren CEO Gary Spirnak.)

Why would anyone choose so challenging a locale to generate electricity? For one, the solar energy available in space is eight-to-ten times greater than on earth. There’s no atmospheric or cloud interference, no loss of sun at night, and no seasons. That means space solar can be a baseload resource, not an intermittent source of power. In addition, real estate in space is still free (if hard to reach). Solaren needs to acquire land only for an energy receiving station. It can locate the station near existing transmission lines, greatly reducing delays that face some renewable power projects sited far from existing facilities.

Yeah, well good luck PG&E!

Wikipedia has a good entry on SBSP here. Scale and cost are probably the biggest problems. You probably need more than a factor of 10 more drop in launch costs. The space community has been promising such a drop was just around the corner for decades, now.

It seems all but inconceivable that you could get the cost to drop that sharply without economies of scale and a learning curve driven by a massive number of regular launches. But who is going to pay for all those incredibly expensive space-based solar systems before the cost drops?

This is a classic chicken and egg problem, compounded by the fact that there is no guarantee you will actually get the cost drops even with large-scale deployment, so all of your money is at grave risk.

The risk is even greater because land-based solar baseload (or load following or dispatchable solar) — aka Concentrated solar thermal power — is practical and scalable now, and certain to be much cheaper. And land-based PV is poised to drop in cost sharply, and will ultimately have access to tremendous land-based storage through plug-in hybrid and electric cars.

On the even more skeptical side, here is the full email from Hoffert:

The PG&E deal is a scam. Pure and simple. We don’t need to study it in detail any more than one needed to study Bernie Madoff’s investment scams. There’s no way to do this any more than there is a way to get 12% return on investment consistently regardless of the economy. Didn’t stop investment in Madoff and it may not stop investment in this harebrained scheme.

There’s no way to get 200 Megawatts from orbit with microwave beaming by 2016 from private sector investment. The infrastructure to do it efficiently with microwaves requires huge structures in orbit and in-space assembly by robots. This is very far from existing technology. Microwaves are the wrong way to start a space solar power business. What we can do in a few hundred kilowatts with laser beaming to PV modules on Earth in a five year time frame because there’s no in-space assembly needed and single-launch vehicles could likely do it.  This could realistically lead to a buildup of a viable orbital and power industry. Even so, we will need major up-front money to test the idea from the feds. The promoters of the PG&E deal idea say they’ll provide a thousand times more power and do it all from the private sector. Might as well say we’re ready to go to the Moon or Mars with private sector financing.   The physics of this is very well understood by the research-active SBSP community.

Too bad, because when it all unravels it will be a major setback for space solar power.  Ken [Caldeira], this is very much like your experience with the company that wants to get rid of CO2 in seawater by a proprietary process that violates basic chemistry. Their CEO says he has special insider knowledge to do this, and so does the company pushing this space solar power deal.  His defense it that he took many companies public. These ideas get as far as they do most because people making business decisions about alternate energy are often scientific illiterates. There are real technological and scientific hurdles, showstoppers, that is;  and there are often potential effective technical and scientific approaches around them.

The problem is not knowing the difference. It’s a much a disaster to overestimate the prospects for near-term profit based on flawed physics as to underestimate the longer-term potential of a new technology based on the opportunities that physics does provide.  As Richard Feynman sagaciously observed, “You can’t fool Mother Nature.”  If only we didn’t have to deal with those idiotic Homo sapiens primates inhabiting this planet. All very depressing because I’m a strong advocate space solar power technology.

Marty Hoffert
Professor Emeritus of Physics
New York University

And then there’s this amazing story in Wired, “Hurricane-Killing, Space-Based Power Plant” based on Solaren’s 2006 patent for “altering weather using space-born energy” (see inset figure from patent below, click to enlarge).

Many readers of the original post were concerned the device could be used as a weapon.  Not so far-fetched an idea now “” at least no more far-fetched than Solaren’s plan to weaken or alter hurricanes from space.

This is a self-inflicted wound by Solaren on its own credibility.

Then we have the life-cycle emissions issue. It takes a massive amount of rocket fuel to put stuff in orbit.

Solaren CEO Gary Spirnak glosses over this entire issue in his interview with Marshall on the web (here):

Q: Is the renewable energy generated from this project completely carbon-free?

A: Yes. Solaren’s SSP energy conversion process is completely carbon-free.

Q: How will this project impact the environment?

A: The construction and operations of Solaren’s SSP plant will have minimal impacts to the environment. The construction of the SSP ground receive station will have no more environmental impact than the construction of a similarly sized terrestrial photovoltaic (PV) solar power plant. Space launch vehicles will place the SSP satellites into their proper orbit. These space launch vehicles primarily use natural fuels (H2, O2) and have an emissions profile similar to a fuel cell. When in operation, the Solaren SSP plant has a zero carbon, mercury or sulfur footprint. In addition, the high efficiency conversion of RF energy to electricity at the SSP Ground Receive Station does not require water for thermal cooling or power generation, unlike other sources of baseload power (nuclear, coal, hydro).

Uhh, not quite. The solar energy is carbon free (other then the manufacturing of the cells which is typically recovered in one or two years of operation).

But I’d hardly call H2 — hydrogen– a “natural fuel.” Today, NASA gets its hydrogen from natural gas in a process that generates large amounts of carbon dioxide. And then it uses a huge amount more energy to get the hydrogen into the Space Shuttle. As I discuss in my book, The Hype about Hydrogen:

At atmospheric pressure, hydrogen becomes a liquid only at the ultra-frigid temperature of -253 °C (-423 °F or 20 K), just a few degrees above absolute zero. It can be stored only in a super-insulated tank, known as cryogenic storage.

NASA uses liquid hydrogen as a fuel for the space shuttle, along with liquid oxygen. Some 100 tons or nearly 400,000 gallons of liquid hydrogen are stored in the shuttle’s giant external tank. To fuel each shuttle launch, 50 tanker trucks drive several hundred miles from New Orleans to Kennedy Space Center in Florida. We have a great deal of experience shipping liquid hydrogen: Since 1965, NASA has trucked more than 100,000 tons of liquid hydrogen to Kennedy and Cape Canaveral….

The process of liquefying hydrogen requires expensive equipment and is very energy-intensive. Refrigeration processes have inherent efficiency limitations, and hydrogen liquefaction requires multiple stages of compression and cooling. Some 40% of the energy of the hydrogen is required to liquefy it for storage….

A major challenge facing liquefied hydrogen is evaporation. Hydrogen stored as a liquid can boil off and escape from the tank over time. NASA faces this in the extreme: The agency loses almost 100,000 pounds of hydrogen each time it fuels up the shuttle, requiring NASA to truck in far more hydrogen than the 227,000 pounds needed by the main tank.

From a global warming perspective, even with large, centralized liquefaction units, the electricity consumed would be quite high. According to Raymond Drnevich of Praxair, a leading supplier of liquefied hydrogen in North America, the typical power consumption is 12.5 to 15 kWh per kg of hydrogen liquefied. Since that electricity would come from the U.S. electric grid, liquefying 1 kg of hydrogen would by itself release some 17.5 to 21 pounds of carbon dioxide into the atmosphere for the foreseeable future. Burning one gallon of gasoline, which has roughly the same energy content as 1 kg of hydrogen, releases about the same amount–20 pounds of carbon dioxide into the atmosphere. So even allowing for the greater efficiency of hydrogen fuel cell vehicles, if liquefaction is a major part of the hydrogen infrastructure, it would be exceedingly difficult for hydrogen-fueled vehicles to have a net greenhouse gas benefit until the electric grid is far greener than today (that is, has far lower carbon dioxide emissions per kilowatt-hour).

Yes, you could make the hydrogen from renewable sources — and liquefy it with renewable sources. But there is no prospect that can be done for anything less than an exorbitant cost, which would drive up the price of each launch enormously.

Yet consider the email response I got from the company in response to my question “Does somebody have a lifecycle CO2 or GHG emissions calculation per kWh given the fuel needed to launch this stuff?”  Cal Boerman, Director Energy Services for Solaren, replied:

Solaren plans to use launch vehicles (Atlas V/Delta IV Heavy Class) that primarily use liquid hydrogen and liquid oxygen for fuels. The resulting emissions are water. These fuels are formed via electrolysis. The Wikipedia definition is: Electrolysis of water is the decomposition of water (H2O) into oxygen (O2) and hydrogen gas (H2) due to an electric current being passed through the water. Solaren assumes the electricity used for this process was generated from clean resources.

Therefore the lifecycle environmental impact per kW-hr is negligible. Also, we do not use solid rocket motors so there is no added pollution from them.

Hope this Helps

Well, It helps me understand how little Solaren has thought about this important issue.  Electrolysis is good for generating pure hydrogen, but it is incredibly electricity intensive (duh) as is making liquid hydrogen for transport.  Presumably a lot of this is done at night when electricity is cheap “” if someone can find information on who exactly makes hydrogen for NASA, I’d love to see it.  All I could find is this 2002 article that says it is done near New Orleans using ” technology that releases large amounts of carbon dioxide into the atmosphere.”  Plus they lose a lot of hydrogen through evaporation from the trucking.  And of course the trucking uses a lot of fossil fuels.

Making hydrogen from renewable-based electrolysis would probably triple the cost of the fuel.  And if Solaren really thinks it can cut launch costs by the factor of 10 or more needed to make this entire effort viable, then it can’t be tripling the cost of the fuel.

PG&E concludes

From PG&E’s perspective, as a supporter of new renewable energy technology, this project is a first-of-a-kind step worth taking. If Solaren succeeds, the world of clean energy will never be the same.

I don’t think space-based solar should be considered among the plausible climate solutions until and unless someone publishes

  • a realistic cost estimate based on plausible launch costs
  • a full lifecycle analysis of CO2 per kiloWatt-hour using existing launch vehicle emissions.

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31 Responses to Harvard Business Review and Yale e360 hype space solar. Why?

  1. Bob Wallace says:

    One out of three or one out of six?

    #5 Geothermal seems to be possible, approaching likely.

    We’ve got wet rock and a bit of hot rock on line. Hot rock has what would seem to be a temporary engineering problem with drilling.

    #4 Fusion and #6 Solar Satellite seem less likely during the next several decades (my lifetime).

    What are the other three possible solutions that the Harvard Business Review hid behind their pay wall?

  2. anonymous says:

    Cap GHG and let the market sort it out.

  3. Seth Masia says:

    One of them, judging by the illustration, is wave/tide power. That at least is achievable with existing non-exotic technology.

  4. Bob Wallace says:

    ecostew – When you find things that you think we all should read would you please take a moment to write a short statement of the content?

    It would be great if you could write a short summary and then let us go to the site if we want more detail.

    Some of us don’t have “instant” download connections and generally don’t bother clicking on a link unless we feel it will hold something of interest to us.

  5. Mike#22 says:

    From Air Products website: “Air Products produces over 1.25 million tonnes of hydrogen per year and has six liquid hydrogen facilities and seven hydrogen pipeline systems around the world. It has been involved in the production and supply of hydrogen for over 50 years and has supplied all the liquid hydrogen for NASA’s space missions.”

  6. ecostew says:

    Bob – will do from now on.

  7. Mike#22 says:

    Also from Air Products website: “The majority of merchant hydrogen is produced by a process called steam methane reforming. Hydrogen is generated from a hydrocarbon (such as natural gas) and water at high temperatures in catalytic reactors.”

  8. Jeff Huggins says:

    Very Much ON Topic, And Slightly Off Topic

    When we discuss matters purely in terms of physical science and in terms of scientific/technological feasibility (that is, completely aside from economic feasibility and other economic or social factors), that’s one thing. And those are, of course, highly relevant and important discussions.

    But, when we discuss things in terms of their relative “economic” feasibility, competitiveness, and economic attractiveness, it’s VITALLY important to go down to bedrock and to keep in mind first principles, especially when considering such important matters as the climate and energy problems.

    (I’m not saying this as a commentary/critique on the current post: Instead, I’m trying to make a broader point about what is missing, quite often, in our thinking about these things.)

    In many — certainly most — discussions of relative economic feasibility and competitiveness, comparing different sources of energy and related technologies, vital things are taken as “givens” that are themselves things that we (humans) invent, define, and can change.

    These things that we take as “givens” — these unexamined assumptions — quite often unnecessarily pre-determine the outcome of the analysis. They often blind us to things that CAN be changed and (often) SHOULD be changed. They often prevent us from seeing viable solutions as viable solutions.

    Without going into a whole lengthy discussion, consider the following:

    One of the key reasons that some great CURRENT technologies and approaches are seen as “not quite feasible yet”, economically speaking, or “not attractive”, or “not ready for prime time” is the fact that we don’t acknowledge that there is a REAL cost to dumping CO2 into the atmosphere. In other words, we don’t yet “value” (in real terms) atmospheric health, the health of the climate, and even human sustainability. That — of course — is both an error and a problem. THAT is an inaccurate judgment. That is a result of human choices regarding value, in a very real way. THAT can be changed, and should be changed.

    Put more concretely, any conclusion such as “CSP is not quite economically feasible or attractive, yet, for large-scale deployment as a major solution to the climate and energy problems” is NOT a sound conclusion in the (very real) sense that it is itself dependent on the highly inaccurate view that pouring CO2 into the atmosphere will have no cost AND on the mere human value judgment (and not an informed one) that doing so should have no cost. In other words, such a conclusion is based on an error that should be corrected and on a value that should be corrected. Or (if you already hold the corrected value), the correct and well-founded value must be manifested in terms of a carbon price.

    Also, of course, labor (the time and efforts of human individuals) is a factor at the very bedrock of economic considerations. But consider this: The net result of our current (“man-made”) complex web of value judgments, tax policy, economic flows, and so forth is this, apparently: We would “rather” pay someone (ONE person) on Wall Street $100 million a year than pay two thousand people $50,000 a year to help create plants, transmission, and other infrastructure to solve our climate and energy problems.

    Many, many, many people want or need meaningful employment. A labor pool exists, at the most foundational level of consideration. Yet, apparently — through our individual choices, tax policy, employment policies, and so forth — we would “rather” employ huge numbers of people in fast-food joints, programming video games, selling us trinkets, and so forth, than employ them in ways that help build the means by which we can generate clean energy, gain energy independence, and protect the climate.

    My point is this: We arrive at many “conclusions” that are false, incorrect, and unnecessary ones. We do so by taking some things as “givens” that AREN’T really “givens” and that can indeed be changed if we really want to solve our largest REAL problems. We make assumptions that are UNexamined. (Socrates would be having fits these days.) Many economists are letting us down. (Indeed, it’s unclear to me how many economists have much of an understanding that goes down to the bedrock level and down to the level of “first principles”, not founded on assumptions that are themselves incorrect or unnecessary.)

    I question whether we can solve our biggest problems without going down to the bedrock level, making sure our thinking is grounded in first principles, examining assumptions, and changing those things that we can change and that SHOULD be changed.

    Einstein said, “The significant problems we have cannot be solved at the same level of thinking with which we created them.” Judging from his life and many of his other quotes, he wasn’t only, or even primarily, talking about matters of pure science or technology. Instead, he must certainly have been talking about things such as what choices we humans make, how well we reflect our values in those choices, how we make public decisions, and all of the related “how we choose to live” matters.

    Be Well,


  9. Bob Wallace says:

    Found two, er, all three. Clicked on the link and the first two were part of the teaser. The third mentioned in the “Executive Summary”…

    “1. High Winds

    Conventional wind turbines stop when the wind dies. Turbine-bearing balloons or rotors could intercept powerful, reliable winds 1,000 to 15,000 feet up.”

    This one sound likely. At least feasible enough that people are starting to prototype it.

    “2. Green Crude

    Biofuels made from plant oils require multistep harvesting and processing. Genetically engineered algae could streamline production by continuously secreting oil to be refined into transport fuel.”

    Again, possible. At least for transportation purposes that will bear a higher fuel cost such as long distance air travel. I’d look for electricity to force liquid fuels out of other transportation modes if battery technology continues to improve.

    3. “wave power from the ocean”

    Fairly likely since it’s already being done. But having spent some time on the open ocean I wonder if wave tech is going to be cost effective. The ocean is a very hostile environment to machines. It may be that wind, solar, geothermal, and biomass are going to price wave (not necessarily tidal) energy out of the market.

    So, I’d say “maybe four out of six” in my lifetime….

    [JR: But only 2 at most are scalable, if that.]

  10. Leland Palmer says:

    Perhaps the financial elite class thinks that a power satellite, supporting a small habitat, added later, might make a good hiding hole after they and their ilk have destroyed this biosphere?

    It’s all I can think of. Certainly space solar is not likely to solve the runaway global warming problem.

    Maybe it’s just Lockheed Martin and Boeing trying to drum up a little business?

    Maybe they want to use it to power a “pain beam weapon from space” to prevent immigration of the dark skinned masses from south of the border?

    Here’s a pain beam that can be fired from aircraft:


    Microwave weapon will rain pain from the sky

    THE Pentagon’s enthusiasm for non-lethal crowd-control weapons appears to have stepped up a gear with its decision to develop a microwave pain-infliction system that can be fired from an aircraft.

    The device is an extension of its controversial Active Denial System, which uses microwaves to heat the surface of the skin, creating a painful sensation without burning that strongly motivates the target to flee. The ADS was unveiled in 2001, but it has not been deployed owing to legal issues and safety fears.

    Nevertheless, the Pentagon’s Joint Non-Lethal Weapons Directorate (JNLWD) in Quantico, Virginia, has now called for it to be upgraded. The US air force, whose radar technology the ADS is based on, is increasing its annual funding of the system from $2 million to $10 million.

    The transmitting antenna on the current system is 2 metres across, produces a single beam of similar width and is steered mechanically, making it cumbersome. At the heart of the new weapon will be a compact airborne antenna, which will be steered electronically and be capable of generating multiple beams, each of which can be aimed while on the move.

    This seems like a typical elite response. Don’t stop the global warming, beam pain on poor people from the sky, to stop the resulting immigration.

  11. ecostew says:

    NCAR has a bit more information than the WaPo on the Science article and a great graph:
    Arctic Warming Overtakes 2,000 Years of Natural Cooling
    September 03, 2009

    BOULDER—Arctic temperatures in the 1990s reached their warmest level of any decade in at least 2,000 years, new research indicates. The study, which incorporates geologic records and computer simulations, provides new evidence that the Arctic would be cooling if not for greenhouse gas emissions that are overpowering natural climate patterns.

  12. Andy Revkin says:

    I’m not sure why you use Marty Hoffert to throw cold water on orbiting solar when he’s one of the most vocal proponents (despite being turned down by Arpa-E’s “transformational” energy office): http://bit.ly/dotSpaceSolar

    [JR: Because he generally likes this sort of thing. He was throwing cold water on Solaren. I'm happy to throw cold water on the general idea. I was surprised Yale discussed Solaren without mentioning the myriad critiques.]

  13. Chris Winter says:

    He’s not throwing cold water on SBSP in general — only on Solaren’s patently ridiculous plans (pun intended.) And he’s right to do so.

    There’s no way they can launch enough equipment to generate 200MW of solar power by 2016, much less have a complete SSP satellite ready to beam power down to a ground station. This is just a matter of logistics: the world won’t have enough uncommitted launch capacity.

    They might get closer if they plan on using Stirling engines instead of photovoltaics. But even so I don’t see how they can get a plant of that size on orbit and working in time. Also, space-qualified solar-driven Stirling-engine generators are not as mature as PV arrays, and I wonder about the reliability of inaccessible rotating machinery.

    As for their patented hurricane-stopper, any microwave beamer with that much punch could have a lot of military uses.

    All of which makes me curious about the backgrounds of the people running Solaren.

  14. hapa says:

    adding to mike#22, this page from a few years ago summarizes industrial hydrogen production

    NASA is about 1% of the demand. petroleum refining is about 67%. … hmm, a factor in choosing launch sites? … no, i guess launching over the ocean, with high rotational velocity, was the main concern.

  15. hapa says:

    gummint docs call these companies “hydrogen suppliers”

  16. Jeff Huggins says:

    Harvard Business Review and Harvard Business School

    I would very much like to see the Harvard Business Review put its very best minds together (reaching also into the other parts of Harvard) to write a thorough article or series of articles on the ethical dimensions of the matter and on the genuine responsibilities of businesses, and of individuals in business, in relation to the climate and energy problems.

    Indeed, in some very real ways, given the positions and prominence of HBR and HBS and Harvard itself, it would be unethical and irresponsible NOT to do so.

    I’ll mention just a few tidbits, as matters of context:

    A Professor at Harvard Business School, William George, who also writes leading books about business leadership and values, is a Board member of ExxonMobil. He’s been a Board member for quite some time.

    Meanwhile, ExxonMobil products generate over 1 Trillion Pounds of CO2 annually, when used, according to a simple approximate calculation. And that doesn’t include CO2 generated during exploration, production, logistics, refining, and distribution.

    Meanwhile, Rex Tillerson, ExxonMobil’s Chairman and CEO, quoted Bertrand Russell about caring for the world of our grandchildren, a couple years ago, and more recently said (in The New York Times) that ExxonMobil will just keep doing what it does best — selling us oil and gas — in upcoming decades!

    Finally, I’ll quote Dr. Drew Gilpin Faust, Harvard’s first female President (with a congrats to Dr. Faust!):

    “It is urgent that we pose the questions of ethics and meaning that will enable us to confront the human, the social and the moral significance of our changing relationship with the natural world.”

    For these reasons and others, I think that the HBR and HBS SHOULD (quite literally, morally speaking) deeply examine and address the ethical responsibilities of businesses and business leaders to be honest, responsible, and proactive in addressing these immense problems we face together as humankind.

    Sincerely and With High Expectations of Harvard,

    Jeff Huggins
    Harvard Business School, class of 1986, Baker Scholar
    U.C. Berkeley, chemical engineering, class of 1981
    McKinsey and Company, 1986-1990
    Concerned parent and citizen
    Los Gatos, CA

  17. Eli Rabett says:

    FWIW, PG&E is not paying a dime until Solaren or whomever delivers. Lots of utilities are signing such agreements with every hare brained (Eli knows) energy generating scheme on the planet. They waive them at the regulatory commissions and the public, as in we are investing in X.

    Get back to us when they actually pay money up front.

    On the other hand, Hoffert is also selling sunshine. In his sales pitch he refers to the efficiency of turning electricity into light in a laser diode (50%), but in fact, you can’t use a diode array to transmit the light to earth they are too divergent. Even Hoffert admits that you need to pump another laser (he references NdYAG) and that step is a lot less efficient so you end up with <20% efficiency electrons to light and most probably worse, but that efficiency does not appear in his calculation. There are other obvious problems.

    Yet, Eli does understand that Blacklight Power is selling shares

  18. Anna Haynes says:

    I’m curious about e360′s funding. They say “We are funded in part by grants from the William and Flora Hewlett Foundation and the John D. and Catherine T. MacArthur Foundation.”, but that leaves quite a bit of wiggle room.

    When I emailed e360 (at yale.edu) to ask who their other funders are, I didn’t get a response.

  19. Sasparilla says:

    I want to mention that we currently do not have invisible columns of death (the intense microwave or laser beam that delivers the power in a focused way to the surface power collector) that people or animals could fly through. Imagine the lawsuits (if one could survive flying through it).

    Considering the difficulty and expense with putting large payloads into geosynchronous orbit (and the inability to do any servicing at geosynchronous orbit ~21k miles up if something didn’t quite work or broke down, the shuttle orbits at around 150 miles up or so) – this idea is impractical, not to mention very dangerous for anyone in the air around the “downlink”.

    Its a solution in search of a need – which doesn’t exist.

  20. Bob Wallace says:

    Sarsaparilla, the systems that I have seen purposed use a microwave signal that is not concentrated, but dispersed over a square kilometer or so. Birds could fly though without harm.

    And installation/repair would be done with robots, not people. And that seems to be somewhat feasible.

    Getting the materials up into orbit is the sticker as far as I can see.

    And I think it likely that well before lift prices drop that much we are going to fill our energy needs with things such as geothermal, the dry rock sort….

  21. Steve says:

    I’m surprised the luftmenschen at Harvard and Yale didn’t include a plan to tether the earth to a ginormous solar sail and tow it a few hundred thousand miles further from the sun. That would cool things off, too. This just isn’t that hard. Make fossil fuels – and any other fuel that emits atmospheric toxins – illegal. Phase them out – all of them – over 10 years. I’ll bet you dollars to donuts that new solar and battery technology will magically appear – without requiring Buck Roger’s intervention.

  22. Marcus says:

    Plus, SimCity taught me as a kid that space-based solar microwaves occasionally miss their target and light random buildings on fire…

  23. There have been so many articles over the past year on space solar (the National Space Society proudly displays a running inventory at
    http://www.nss.org/settlement/ssp/) that I suspect it says more about people’s space fantasies than it is about common sense, fiscally prudent, and least-risk options. I was shocked to see Solar Today magazine run a piece, which just fans the fantasies and distracts from the vast pool of immediate actions already available.

  24. Mike#22 says:

    Not to nit pick or anything, but the Atlas V uses a liquid oxygen/kerosene engine, and SRBs, solid rocket boosters. Stay upwind after launch.

  25. Cyril R. says:

    SRBs would be unattractive for this plan because it’s energy intensive to make (even more primary energy required than for hydrogen). I believe aluminium is typically used as solid rocket fuel. This must then be made from electrolysis with electricity from low carbon sources, which is quite a bit less efficient than hydrogen electrolysis. It is also not very clean in terms of chemical emissions to air. Then there’s also the oxidizer which will be needed for SRBs.

    Hydrogen fuel is pretty much the only realistic option for space solar.

    I think the biggest obstacle isn’t technical but political. The weapon implications of space solar are quite severe. The biggest economical risks may be residual ones like the continued reductions in the cost of land based solar, especially when combined with advances in storage technology. This risk is not related to space based solar itself so will be difficult to deal with for companies working on space based solar development. Basically they first have to get a full scale space solar system going and then get going on the learning curve, that means a lot of catching up to concentrating solar thermal electric and (concentrating) photovoltaics.

  26. Keith Henson says:

    Sept. 1 (Bloomberg) — Mitsubishi Electric Corp. and IHI Corp. will
    join a 2 trillion yen ($21 billion) Japanese project intending to
    build a giant solar-power generator in space within three decades and
    beam electricity to earth.

    A research group representing 16 companies, including Mitsubishi Heavy
    Industries Ltd., will spend four years developing technology to send
    electricity without cables in the form of microwaves, according to a
    statement on the trade ministry’s Web site today.




    “Transporting panels to the solar station 36,000 kilometers above the
    earth’s surface will be prohibitively costly, so Japan has to figure
    out a way to slash expenses to make the solar station commercially
    viable, said Hiroshi Yoshida, Chief Executive Officer of Excalibur
    KK, a Tokyo-based space and defense-policy consulting company. “These
    expenses need to be lowered to a hundredth of current estimates,”
    Yoshida said by phone from Tokyo.

    I have run the analysis and get close enough to the same number. Current price to GEO, $20,000/kg; if space based solar power is to displace fossils by being substantially less expensive (1-2 cents per kWh) the cost must come down to $100/kg, a factor of 200.

    This is a design to cost problem. Start with the rocket equation:

    For a serious power satellite program you need 100 t/hr to GEO, at $100/kg. Try a two stage to GEO. Requires 14 km/sec, get the first 4 km/sec with a mass ratio 3 hydrogen/oxygen rocket. Four km/sec is easy to do, ask Elon Musk. To get the remaining 10 km/sec with a mass ratio 2 means an average exhaust velocity of 15km/sec.

    Because you stage far short of LEO, the second stage must have
    relatively high thrust so ion engines won’t do. Ablation laser
    propulsion (well understood physics) with an average exhaust velocity
    of 15 km/sec will provide over a g at 4 GW. The suborbital path keeps
    the second stage out of the atmosphere long enough (15 minutes) for
    the laser to push the second stage into geosynchronous transfer orbit.
    (see Figure 4 here http://www.theoildrum.com/node/5485)

    At 4 payloads an hour (working the laser full time), each payload to
    GEO needs to be 25 t. So the mass ratio 2 laser stage is 50 t, the
    first stage 50 t (16%structure) and 200 t propellant. On takeoff it
    masses 300 tons, less than a 747. A large airport handles a lot more
    traffic than eight 747 takeoffs and landings an hour.

    Hard engineering and not cheap. The laser might eventually cost $40
    billion. To get started (to positive cash flow) came out to $60
    billion on a first cut proforma analysis. (Figure 6 same URL)

    A UK company, Reaction Engines, has an inordinately clever approach
    to boost the effective exhaust velocity so as to put payloads (12
    tons) into LEO with hydrogen/oxygen single stage to orbit. What they
    are doing is recovering a lot of the energy that goes into liquefying
    hydrogen and using that to cool and compress air to rocket chamber
    pressures up to 26km and Mach 5+. Google for them.

    The rough financial model uses grid power for the lasers and any source of hydrogen to get started. But as you can see from the spread sheet, power satellite energy is fed back into both. When there is 80 GW of power satellites on line, the internal use is about 10 GW split equally between making liquid hydrogen and powering the lasers.

    Keith Henson

    Added new thoughts from the space elevator conference.

    A lot of the mass of a thermal power satellite is heat sink
    fluid. That can be made from finely ground rock and a little
    gas. Decouples gas pressure from the amount of heat the pseudo fluid
    can carry. Seems a shame to be shipping up sacks of cement dust. We
    are looking into the payback time for a moving cable space elevator
    through L1 to the lunar surface. Existing materials are good enough
    for the cable–without taper. 15 MW is enough to lift 33 tons per
    hour. Feed lunar dirt through a vibratory ball mill and presto heat
    sink fluid. Cost for lunar dirt/heat sink fluid could be as little as a dollar a kg.

  27. We will be able to put stuff in space cheaply enough, including energy and pollution cost, as soon as the space elevator is in operation. See http://www.liftport.com Don’t hold your breath.

    The space elevator will be feasable as soon as we figure out how to make carbon nanotubes both long and strong enough or we figure out how to make diamond nanowire. Again, don’t hold your breath.

    We will be able to get the electricity back down to Earth from a solar power station at 22,000 miles altitude safely and efficiently as soon as we have ambient temperature superconductors that can be threaded into the space elevator cable. Again, don’t hold your breath.

  28. Cyril R. says:

    Actually all the proposed systems use microwave energy densities in excess of 1 kW per square meter which is quite lethal. Brain and other major organ damage being big risks.

  29. Cyril R. says:

    And there wouldn’t be much point in going to safer levels of a few watts per square meter since that makes the land use requirement too big (asides from seriously hampering the overall economics).

    Again, the weapon implications are quite severe.

  30. richard schumacher says:

    The military application for space-based power is to provide reliable power to remote locations. It makes a poor weapon because it’s so big, expensive and easy to attack. Any harm it could do would be done far more cheaply and easily with missiles or bombs.

    Slowly (too slowly) we recognize that eliminating fossil fuels is going to cost a lot, take decades, and in the case of wind and ground-based Solar require thousands of square miles of area for collectors and hundreds of thousands of miles of new transmission lines. Nuclear power at least has the advantage of compactness.