Finding a New Niche for Solar Power?

Solar power is well-suited for small scale and off-grid applications. But without cheap utility-scale storage, the daily time limits on sunshine make large scale solar impractical and exorbitantly expensive. Abengoa Solar, based in Lakewood, CO, and Xcel Energy, Colorado's largest electrical utility, have come up with an idea that may get a foot in the door for larger solar utility projects: mixing solar energy with coal energy.

...a large part of the cost of a solar-thermal plant is the equipment for converting heat into electricity. The Abengoa Solar project will use existing boilers, turbines, generators, and so on, reducing this cost.

"The thing that's attractive about this is you only have to buy the solar field portion of the plant, which is 50 to 60 percent of the cost of the plant," says Hank Price, director of technology at Abengoa Solar. That could effectively make solar-thermal power about 30 to 50 percent cheaper, according to various estimates. That would equate to a range of about six to 12 cents per kilowatt-hour, which is competitive with many conventional sources of electricity. "It's potentially the most cost-effective way to get significant solar power on the grid," he says.

In the new project, because parabolic troughs don't generate sufficiently high temperatures, the heat they produce won't be fed directly into the turbines. Instead, it will be used to preheat water that will be fed into the coal plant's boilers, where coal is burned to turn the water into steam. _TechnologyReview

Because the water going into the boilers will be pre-heated by focused solar heat, less coal will be required to produce the steam that powers the steam turbines.

Whether this approach actually saves money, will require some testing and a great deal of analysis. It is a good idea that has to be proven by hard-headed work.

The problem hanging over the energy sector, preventing a clear analysis of new technologies, is the political crusade over carbon climate catastrophe. If the economics of energy is allowed to be distorted by political crusades, we will all end up much worse off than we are today. We hope that this project, lake all energy projects, can be evaluated in a dispassionate manner.