In Pictures: The World’s Largest Solar Thermal Power Plant

That's a slightly glossed over interpretation of thermodynamics. Perhaps photovoltaics have a higher theoretical efficiency than a thermal cycle plant, but in practice they don't. Thermal cycle power plants are the mainstay of our power generation - nuclear, coal, gas, geothermal - all those power sources make use of a steam based heat to work cycle. We've got 100 years of experience in developing thermal cycle power. Peak photovoltaic efficiency is currently ~20%, while most affordable cells are closer to 10-15%. A simple cycle thermal plant might have an efficiency of 30-40%. It'll be some time before photovoltaics are more efficient for a given area of collecting space.

Cost is a different question. Photovoltaics have fallen dramatically in cost recently. As the space taken up by a solar plant isn't really an issue (the collecting area could take up 10 times more space without really impacting anything), the winner in solar energy will be the cheapest option per kWh.

The amount of energy extracted is minuscule. Digging coal an uranium out of the ground aren't side effect free either.

Capacity factor is location- and weather-dependent, and not always known for certain with a new technology (or in this case a known technology this much larger).

Concentrated solar thermal also allows for storage, making the capacity factor percentage adjustable, and allowing for on-peak optimization, which would have a lower capacity factor but a significantly higher benefit to the power company.

If it's peak capacity syncs with peak demand for air-conditioning that might work.

Environmentally you would probably do much better (energy wise) by covering the roofs of building in Las Vegas with similar mirrors to lower their albedo and reduce air conditioning use.

Don't know about tarnishing, but for cleaning they most likely use water.

From an article on solar thermal plants in the Middle East [1]:

But harsh desert conditions in parts of the MENA region generate large amounts of airborne dust which collects on the solar panels used in CSP systems, reducing their efficiency. They need regular cleaning, which consumes large amounts of water.

1: http://m.scidev.net/en/climate-change-and-energy/renewable-e...

> I have not seen the math but in order to achieve any meaningful scale it needs to be huge

How can you make a statement like that? If you're not aware of the mathematical basis for the plant then you can't quantify "huge". You're either regurgitating something you read elsewhere without any real understanding, or you're simply making untrue statements.

If this is a ridiculous concept, what do you propose instead? Further oil exploration? More coal? This project is making a meaningful step towards reducing our dependence on fossil fuels. If you want to criticise, fine, but please at least take the time to properly understand the costs involved and the alternative options.

You an see an early version of one of these in Barstow, if that's what you're thinking of. There is a functional one in Spain as well (http://en.wikipedia.org/wiki/PS10_solar_power_tower)

Anyway you may be right that the tower concept isn't going to last long, but the troughs have been shown to last decades (see Victorville, California) and obviously they have the same issue of dust... so there must be a known solution for that engineering challenge.

They probably keep it at under 1000 degrees by circulating a molten salt at whatever rate is necessary to carry away the heat.

No matter what the target is made out of, without that circulation to withdraw heat, it wouldn't get much hotter before it vaporized and there was no target. No doubt it'd be possible to get a much higher temperature if that was the goal.