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 HBRfigure above), so perhaps that tells you their time horizon is … 50years 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.” Asidefrom discussing the military’s interest, which may not be totallybenign and in any case is largely irrelevant to the question ofcommercial viability, the piece discusses the deal Solaren Corporationhas with Pacific Gas & Electric (PG&E) “to provide 200megawatts of power — about half the output of an average coal-firedpower 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. Wedon’t need to study it in detail any more than one needed to studyBernie 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.

Certainlyit is worth pursuing any genuine low-carbon baseload power source if itcan be practical and scalable — and affordable, which I would put at$0.15 a kilowatt hour or less for. The problem with space solar isthat, like hydrogen fuel cell cars, there is little chance it could beaffordable until it is massively scaled up — and no guarantee that itwould be practical and affordable even then. That’s one reason majorutilities 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 ofsolar thermal and photovoltaic power” is looking in to it. JonathanMarshall, 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 apower purchase agreement with Solaren Corp., a Southern Californiacompany 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 inearth orbit, then convert it to radio frequency energy for transmissionto a receiving station in Fresno County. From there, the energy will beconverted to electricity and fed into PG&E’s power grid. (Seeinterview with Solaren CEO Gary Spirnak.)

Why would anyone choose so challenging a locale to generateelectricity? For one, the solar energy available in space iseight-to-ten times greater than on earth. There’s no atmospheric orcloud interference, no loss of sun at night, and no seasons. That meansspace solar can be a baseload resource,not an intermittent source of power. In addition, real estate in spaceis still free (if hard to reach). Solaren needs to acquire land onlyfor an energy receiving station. It can locate the station nearexisting transmission lines, greatly reducing delays that face somerenewable 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 needmore than a factor of 10 more drop in launch costs. The space communityhas 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 dropthat sharply without economies of scale and a learning curve driven bya massive number of regular launches. But who is going to pay for allthose incredibly expensive space-based solar systems before the costdrops?

This is a classic chicken and egg problem, compounded by the factthat there is no guarantee you will actually get the cost drops evenwith 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. Andland-based PV is poised to drop in cost sharply, and will ultimatelyhave access to tremendous land-based storage through plug-in hybrid andelectric 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’tneed to study it in detail any more than one needed to study BernieMadoff’s investment scams. There’s no way to do this any more thanthere is a way to get 12% return on investment consistently regardlessof the economy. Didn’t stop investment in Madoff and it may not stopinvestment in this harebrained scheme.

There’s no way to get 200 Megawatts from orbit with microwavebeaming by 2016 from private sector investment. The infrastructure todo it efficiently with microwaves requires huge structures in orbit andin-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 PVmodules on Earth in a five year time frame because there’s no in-spaceassembly needed and single-launch vehicles could likely do it.  Thiscould realistically lead to a buildup of a viable orbital and powerindustry. Even so, we will need major up-front money to test the ideafrom the feds. The promoters of the PG&E deal idea say they’llprovide a thousand times more power and do it all from the privatesector. Might as well say we’re ready to go to the Moon or Mars withprivate sector financing.   The physics of this is very well understoodby the research-active SBSP community.

Too bad, because when it all unravels it will be a major setback forspace solar power.  Ken [Caldeira], this is very much like yourexperience with the company that wants to get rid of CO2 in seawater bya proprietary process that violates basic chemistry. Their CEO says hehas special insider knowledge to do this, and so does the companypushing this space solar power deal.  His defense it that he took manycompanies public. These ideas get as far as they do most because peoplemaking business decisions about alternate energy are often scientificilliterates. There are real technological and scientific hurdles,showstoppers, that is;  and there are often potential effectivetechnical and scientific approaches around them.

The problem is not knowing the difference. It’s a much a disaster tooverestimate the prospects for near-term profit based on flawed physicsas to underestimate the longer-term potential of a new technology basedon the opportunities that physics does provide.  As Richard Feynmansagaciously observed, “You can’t fool Mother Nature.”  If only wedidn’t have to deal with those idiotic Homo sapiens primates inhabitingthis planet. All very depressing because I’m a strong advocate spacesolar 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 beused as a weapon.  Not so far-fetched an idea now — at least no morefar-fetched than Solaren’s plan to weaken or alter hurricanes fromspace.

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 haveminimal impacts to the environment. The construction of the SSP groundreceive station will have no more environmental impact than theconstruction of a similarly sized terrestrial photovoltaic (PV) solarpower plant. Space launch vehicles will place the SSP satellites intotheir 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 orsulfur footprint. In addition, the high efficiency conversion of RFenergy to electricity at the SSP Ground Receive Station does notrequire water for thermal cooling or power generation, unlike othersources of baseload power (nuclear, coal, hydro).

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

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

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

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

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

A major challenge facing liquefied hydrogen is evaporation. Hydrogenstored as a liquid can boil off and escape from the tank over time.NASA faces this in the extreme: The agency loses almost100,000 pounds of hydrogen each time it fuels up the shuttle, requiringNASA to truck in far more hydrogen than the 227,000 pounds needed bythe main tank.…

From a global warming perspective, even with large, centralizedliquefaction units, the electricity consumed would be quite high.According to Raymond Drnevich of Praxair, a leading supplier ofliquefied hydrogen in North America, the typical power consumption is12.5 to 15 kWh per kg of hydrogen liquefied. Since that electricitywould come from the U.S. electric grid, liquefying 1 kg of hydrogenwould by itself release some 17.5 to 21 pounds of carbon dioxide intothe atmosphere for the foreseeable future. Burning one gallon ofgasoline, which has roughly the same energy content as 1 kg ofhydrogen, releases about the same amount–20 pounds of carbon dioxideinto the atmosphere. So even allowing for the greater efficiency ofhydrogen fuel cell vehicles, if liquefaction is a major part of thehydrogen infrastructure, it would be exceedingly difficult forhydrogen-fueled vehicles to have a net greenhouse gas benefit until theelectric grid is far greener than today (that is, has far lower carbondioxide emissions per kilowatt-hour).

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

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

Solaren plans to use launch vehicles (Atlas V/Delta IVHeavy Class) that primarily use liquid hydrogen and liquid oxygen forfuels. The resulting emissions are water. These fuels are formed via electrolysis. TheWikipedia definition is: Electrolysis of water is the decomposition ofwater (H2O) into oxygen (O2) and hydrogen gas (H2) due to an electriccurrent 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 isnegligible. Also, we do not use solid rocket motors so there is noadded pollution from them.

Hope this Helps

Well, It helps me understand how little Solaren has thought aboutthis important issue.  Electrolysis is good for generating purehydrogen, but it is incredibly electricity intensive (duh) as is makingliquid hydrogen for transport.  Presumably a lot of this is done atnight when electricity is cheap — if someone can find information onwho exactly makes hydrogen for NASA, I’d love to see it.  All I couldfind is this 2002 articlethat says it is done near New Orleans using ” technology that releaseslarge amounts of carbon dioxide into the atmosphere.”  Plus they lose alot of hydrogen through evaporation from the trucking.  And of coursethe trucking uses a lot of fossil fuels.

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

PG&E concludes

From PG&E’s perspective, as a supporter of newrenewable energy technology, this project is a first-of-a-kind stepworth taking. If Solaren succeeds, the world of clean energy will neverbe 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.