Reuters has an article on the challenge posed by ever cheaper solar PV power to large scale solar thermal power (which I think will still scale better to very large scale generation, once economies of scale are achieved) - Solar thermal seeks U.S. breakthrough.
Solar thermal power could be close to a breakthrough in the U.S. market, but only if developers can shave costs to beat back competition from photovoltaic (PV) solar systems, and attract the huge sums needed to finance the renewable energy plants.
While the new technology has been touted as a solution toward moving the United States away from its dependence on fossil fuels, it has so far stumbled because of the high price tag for the massive plants.
Solar thermal companies like Brightsource and eSolar, both of which count search giant Google Inc among their investors, and Spain's Abengoa Solar, have technology that concentrates the sun's rays to heat water into steam and drive a generator.
Traditional PV modules made by companies like First Solar and Suntech directly convert sunlight into electricity, and make up the largest chunk of the solar market.
Backers of solar thermal have said it would claim the lion's share of large-scale projects in the United States, but a sharp drop in PV panel prices has drawn much of the market's interest to that technology.
"With panel prices coming down so much for solar PV, solar thermal does not look as cost-competitive anymore," Wedbush analyst Christine Hersey said.
Solar thermal is economical only on a large scale, lifting total project costs into hundreds of millions of dollars, while PV systems can be built piecemeal in smaller steps that are easier to finance.
"It does not make sense to do a (thermal) plant that is less than 100 megawatt (MW)," Cowen & Co analyst Rob Stone said. "That is because of the cost of the steam plant that goes with it."
PV, however, can be used for a wide range of applications, from very large to very small.
"In terms of ubiquity, PV is ultimately going to be the most widely deployed technology just because it's going to show up ranging in size from 500 MW projects all the way down to solar cells on the roof of a hybrid vehicle," Stone said.