Could you explain why?

The alternatives seem simpler, specifically solar thermal collectors[1] where they can be used in conjunction with steam turbines and molten salt heat storage.

The most obvious disadvantage is that energy collection ability drops sharply on clouded days and it relies entirely on clear skies.

[1] http://en.wikipedia.org/wiki/Solar_heating

I don't understand how a solar thermal collector is in any way simpler than a photovoltaic array. Actually, it seems more complex to me. Again, could you explain?

They are simpler than photovoltaics in the sense that a mechanic can repair them. I like them because they:

- Use simple materials, not a bunch of rare earth metals that the USA doesn't have

- Will last as long as you maintain them (to my knowledge) unlike solar panels

- Have better efficiency compared to solar panels

You are right that they are not as "simple" as slapping a panel on a flat surface and wiring it up. Clearly, they are not suited for installation on houses. However, power plants have always used more sophisticated systems because they can handle the tradeoffs to reap the rewards.

This is a bit like saying a vacuum tube TV is simpler than an LCD one because a mechanic can repair it. It's a myopic view.

Are you sure a thermal solar installation will last as long as photovoltaics? Any plant with the efficiency gains you describe has gimballing mirrors, highly thermally cycled metals, steam circuits, and freakin' turbines among other mechanical contraptions all over the place. I see a whole lot of disadvantages compared to a completely solid-state, arbitrarily scalable panel that lasts (conservatively) 50 years.

I realize some places might get really neat solutions out of thermal solar, but I just don't see how it's anything more than a niche. By contrast, photovoltaics have the prerequisites to take over the entire market from the bottom up. They are our future.

Solar panels are nice in that if one fails, you just replace it. That's also why they are not nice; all the upsides and downsides of a disposable unit-based system.

I'm curious where you are getting this "conservative" estimate of 50 years. I typically hear 20 years, 40 years tops.

photovoltaics might be the future, but they aren't the today as best I can tell. They are inefficient, and much like the Prius batteries people like to talk about, are pretty environment-unfriendly to manufacture.

I would speculate (but don't know) that concentration of the heat energy to power a more conventional steam generation plant would be more efficient, at least beyond a certain scale. The best photovoltaic panels are about 20% efficient under optimal conditions.

They are also closer to the consumer, negating a big chunk of the transmission losses.

Also, while thermal electric plants may be more efficient at large scale, I'm not sure how that works at small scale, or if there is a difference in how much capacity they lose in cloudy weather compared to photovoltaics. Actually, I wonder what the ratio of installed photovoltaics to thermals is per region and generator scale.