I wrote about the Chevron plant that converts solar energy to steam, so that they can recover oil using a smaller carbon footprint.  This Coalinga (CA) plant is pretty darned big.  It’s on some 65 acres and nearly 8000 mirrors that track the sun.  (They are called heliostats.)   And, it yields some 29 MW of steam.

We haven’t heard much about the Ivanpah solar power facility.  This one is even bigger than the Chevron facility, with some 170,000 mirrors.  (Yes, that means it’s more than 20X the size of the Chevron one.)  And, the Mojave Desert facility has consumed some $ 2.2 billion in its development.  For that price, it was supposed to yield 1 million MW of electricity, using BrightSource Energy Inc technology while being run by NRG Energy Inc.

But, now that it’s been running for 15 months, the yield is only 40% of what was promised.  Of course, NRG blames it on faulty equipment (who chose this design again?)- such as leaky pipes to the water boilers, vibrating steam turbines, and the like.

But, the real conditions are worse than that.   The concept was to use natural gas for about an hour (prior to sunrise) to generate steam- but it seems to need 4 hours to get things to optimal conditions.  But, the lack of sun- that’s something that will make the plant design truly non-functional.   And, cloud cover has greatly exceeded the predicted amount!

Given these facts maybe we shouldn’t have jumped onto heliostats so quickly.  After all, conventional (ok, let’s use the term traditional) solar panels are letting their designers exceed the initial estimates of power development.  (SunPower and the California Valley Soar Ranch are both large facilities doing so.)  These traditional systems are providing 16 Million MW of power.  These are big steps in our adoption of solar power,  but these two units are only  yielding 1% of US electric demand. (By contrast, they are providing 6X the amount of power solar-thermal [heliostat] facilities develop.)

Traditional solar plants are producing their power at lower costs than the heliostats, too.  Instead of the 12 to 25 cents per KWh that is spent at Ivanpah, these other facilities are providing their output at some 5 cents a KWh.

Looks like we need a lot more engineering to get our value from these heliostats.  Assuming they also find a way to deal with the 1000F temperatures that surround the heliostats (frying all living things in the vicinity.)

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