Another One Bites the Dust

Another solar company which received $2.1 billion in loan guarantees from the Obama Administration has gone bankrupt.  The good news is that it has not spent much of that taxpayer money, and its bankruptcy is probably due more to the bankruptcy of its German parent, which in turn is likely related to the huge cuts Germany has made in its feed-in tariff subsidies.

The big asset possessed by Solar Trust is the Blythe solar project, a planned 1000MW facility that apparently has all of its permitting in place.  The Blythe facility was originally going to be a solar-thermal facility, with adjustable mirrors focusing the sun on a central boiler that would in turn power turbines.   This plan was scrapped last year in favor of a more traditional PV technology, and I know local company First Solar has been hoping to save itself by getting the panel deal (First Solar also has been hammered by the loss of German subsidies).

If we take the cost of this planned 1000MW facility as the stated $2.8 billion (of which 2.1 billion would be guaranteed by US taxpayers), we see the basic problem with solar.   A new 1000MW  natural gas powered electric plant costs no more than about $1 billion.  It produces electricity 24 hours a day.  This solar plant, to be the largest in the world, would produce 1000 MW for only a few hours of the day.  That area of desert gets about 7 peak sun hours per day (the best in the country) so that on a 24 hour basis it only produces 292 MW average.  This gives it a total capital cost per 1000 MW of $9.6 billion, making it approximately 10 times costlier than the natural gas plant to build.  Of course, the solar plant has no fuel costs over time, but solar is never able to close the gap over time, particularly with current very low natural gas prices.

Update:  Apparently the $2.8 billion was just for the initial 484 MW so you can double all the solar costs in the analysis above, making the plant about 20x costlier than a natural gas plant.


  1. DrTorch:

    Why go to PV over solar thermal?

    Also, wouldn't it be more correct to compare the 24,000MWhrs of the natural gas plant to to the 7,000 MWhrs of the solar plant? After all, the peak power production is the same, it's the energy production that varies.

  2. Bobby L:

    I see the problem: they just needed 210 more MW, then they would have had the 1.21 GW needed to go into the future and grab the developed technology and bring it back to today.

  3. Ted Rado:

    Solar thermal has an advantage. There is already a boiler and turbine. During the night, steam can be supplied via natural gas. With PV solar, backup must include the whole deal (boiler, turbine,etc.). I have not done the calcs, but I would think that, if backup was included in the comparison, solar thermal would be better. Niether, of course, is any good without massive subsidies.

  4. Philip Ngai:

    DrTorch: that's where the 292 comes from.

    Rado: backup is never included in pricing these things. If it seems like fraud to you, I wouldn't argue.

    What's interesting to me is that PV is currently cheaper than solar thermal but still 20x more than natural gas. Where are the costs in solar thermal? I see two major components to solar thermal: the collector or reflectors, and the heat to electricity conversion (turbines and generators).

    A natural gas plant needs turbines and generators too. Are the turbines and generators for solar thermal a lot more expensive?

    Or does the high cost of solar thermal come from the collector or reflectors? Because the latter are just mirrors and I would have guessed they would be cheap. I could be wrong.

  5. markm:

    Philip: Don't forget the costs of mounting the mirrors. Mounting a fixed mirror array will cost the same as mounting the same area of PV panels. (The mirrors are much lighter, but it's the wind loads that determine the required strength in either case.) I've reviewed budgets for house-sized PV arrays, and just the materials to mount the panels cost about half as much as the panels themselves. If I'd figured union labor rates, the cost of mounting PV panels or mirrors probably exceeds the cost of the PV panels themselves.

    And that's for fixed mirrors, which either require moving the collector/boiler to follow the sun, or give you a diffuse focus, good for only part of the day, with temperatures and thermal efficiencies never approaching that of a fuel-fired steam plant. Steerable mirrors are probably better, but much more costly.

    Ted: Solar-thermal with a fuel-fired boiler for backup sounds like a better idea, but I'm not sure it survives economic analysis. Solar boilers look nothing like conventional boilers, so the shared part of the system is just the turbines, generators, electrical controls, and the output power lines. The "backup" system will run for more hours and generate more energy than the solar, so it's efficiency and cost effectiveness is paramount. The solar boiler must superheat steam to the same temperature as a good coal-fired plant, which rules out many solar thermal designs that trade off lower thermal efficiencies for cheaper mirror systems. The fuel costs should not be higher per KWH than competitive conventional plants, which makes coal a better bet than natural gas - but can you turn coal boilers on and off quickly enough?

    I don't know about conventional power plants, but I do know that on Navy steam ships, engineering starts work at least 8 hours before the ship is scheduled to leave the dock. Most of that 8 hours is slowly and carefully heating up the boiler. They might be able to get steam up in less than an hour in an emergency, but the added stress will shorten the life of the boiler, etc. (OTOH, it's better than getting shot full of holes...) And this suggests to me that a solar thermal plant will have a substantially shorter life than a 24-hour-a-day coal plant that rarely puts the boilers through the thermal stress of shutting down and starting back up. Also, that steam backup plants will need to keep the boilers hot 24 hours a day.