How far away from competing with coal is solar thermal technology?

Not far, says David Wheeler, a senior fellow at the Center for Global Development. With $4-8 billion dollars of learning curve investments over the next five years or so, a new solar thermal plant would be competitive with a new coal plant.

He looked at the cost of the plants now and then made some reasonable assumptions about how much learning-by-building plants will drive down the cost of the still immature solar thermal tech. People who look at this stuff generally measure this learning rate by the percentage that the price of the tech drops for each doubling in capacity. Different technologies have different learning rates, but you might expect something like 10 or 20 percent.

Looking at those numbers, Wheeler concludes:

We find that the solar thermal investment program is cost-competitive with coal-fired power at extremely low carbon accounting charges—so low, in fact, that there is no reasonable case for delaying the switch to solar thermal power (and, by implication, other renewable technologies with similar learning curves and cost differentials). Using the best available evidence on costs and solar learning curves, we conclude that a focused investment program can drive solar thermal power to cost parity with coal-fired power in five to ten years, for a total cost of four to eight billion dollars.

Here’s a presentation that he and a colleague give detailing the approach: