Solar baseload outshines ‘clean coal’ — and it always will

Concentrated solar thermal power — aka solar baseload — remains hot. The Daily Climate has a nice update:

All told some 60 plants are either under construction or under contract worldwide — with most in either Spain or the United States — for a total capacity just north of 5,700 megawatts

Here is the world list of projects. Here is the U.S. list.I remain as convinced as ever that solar baseload could well be “The technology that will save humanity,” in large part because it is highly scalable, eventually able to achieve 50 to 100 gigawatts a year growth or more.

Indeed, given the immense challenges that coal with CCS faces (see “Is coal with carbon capture and storage a core climate solution?”), I’m still happy, indeed eager, to bet that concentrated solar thermal will continue delivering more power every year this century than so-called “clean coal” — and at a far lower cost per kilowatt-hour.

Solar baseload’s ultimate “trump card” is, of course, storage:

The ability to store power for later use is a holy grail of sorts for renewable energy developers. Wind and photovoltaic plants force utilities to use the power on the spot or dump the load. Various batteries and capacitors are in the works for those technologies, but none so far match the smooth efficiency or low cost of solar thermal’s ability to hoard sunlight.

A plant designed with storage can shunt the hot oil from the mirrors to a giant insulated heat sink — a vat of molten salt, say, or a chunk of concrete or pig iron. Then after the sun sets but while demand remains high, that heat can be tapped to generate steam.

Or if a cloud rolls over a plant’s mirrors, or an afternoon thunderstorm stalls overhead, hundreds of megawatts of juice won’t suddenly drop off the grid. Utility operators can simply tap the tank.

“We’ve sort of stumbled on this thing with storage,” said Tom R. Mancini, program manager for concentrated solar power technologies at Sandia National Laboratories in New Mexico. “The round-trip efficiency is 90 percent…. Solar thermal is made for this.”

Arizona Public Service is building a plant that can keep the sun’s power for six hours past sunset, allowing managers to meet evening demand with midafternoon sun. A utility in Spain hopes to develop a plant that can keep heat for seven. Engineers figure 14 hours or more is feasible.

Until “clean coal” sees this type of enthusiastic global embrace, with dozens of projects around the world, at power prices comparable to other types of new power plants, it will always remain a (CO2) pipe dream.

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