Nobody can fault Ausra for lack of ambition. The solar power-plant maker has released a peer-reviewed paper claiming that solar-thermal electricity could power 90% of the US grid, with enough left over for plug-in hybrid cars. "The company estimates that such a changeover would eliminate 40 percent of the country's greenhouse gas emissions with a land footprint of 9,600 square miles, about the size of Vermont".
"How can that be?", you ask. "Isn't solar power only available when the sun shines?"
The way Ausra's technology works is that mobile reflectors concentrate sun light on pipes. Water goes through them and is heated up enough to produce high pressure steam, which then turns a turbine to generate electricity. The twist is that they also store enough hot water to keep going around the clock, or increase production on demand.
There's an animated version of the picture above.
And if the quote about "the size of Vermont" in the intro scared you, know that it would represent "less than 1% of America's deserts, less land than currently in use in the U.S. for coal mines, and a tiny fraction of the land currently in agricultural use."
Ausra says it can generate electricity for 10 cents a kilowatt hour, which is close to the cost of natural gas, and it expects the price to drop even further. The company has received a lot of attention because of its compact linear Fresnel-reflector technology, and because it lined up two big-name VCs early: Vinod Khosla and Kleiner Perkins, where Al Gore is a partner. It's received $43 million in venture capital, and an additional $30 million at least in venture debt. It's planning a $100 million-to-150 million funding round later this year.
You can read Ausra's study here (pdf).
We're definitely excited about solar-thermal. Right now it has higher efficiency than photovoltaic panels (PVs) (20-40% vs 15-22%) and its price is still coming down relatively fast. That's the important thing: To make it cheaper than coal.
We don't know which approach will succeed - Ausra's or another - but we're glad a lot of R&D; and competition is going on in the field. That's the best way to move forward.
See also: ::Torresol to Build 3 Solar Thermal Power Plants in Spain for $1.24 Billion, ::Solar Thermal Power: Not Forgotten, ::Australian Firm Presents Solar Thermal Storage Concept, ::Ontario Gets 407 Megawatts of Solar Power Contracts, Originally Expected 88 Megawatts