orting large scale CSP last year, aiming to reduce the cost of CSP power to 7-10¢/kWh by 2015 and 5-7¢/kWh by 2020. The DOE estimated that reaching these cost targets could lead to installation of up to 35,000 MW of new generating capacity by 2030 in the US. James Fraser at The Energy Blog commented at the time that it was 5 years too late (given recent commercial activity in the area) and that PV solar may beat these price goals before solar thermal does, but that more solar options are good in any case, as both PV and thin film solar manufacturing will be constrained by availability for materials for some time as production continues to accelerate.
Another estimate from Sandia labs showed solar thermal costs (for solar towers) could fall to around 4 cents per kWh by 2030.
Another variant on the solar thermal power theme are Stirling engine based power plants, which generate electricity directly rather than first storing the energy as heat.
Stirling Energy Systems seems to be the leader in this field, with some reports talking about agreements with Southern California Edison and San Diego Gas & Electric for up to 1.75 GW of power. The company recently set a new world record of 31.25% for Solar-to-Grid conversion efficiency.
Other companies pursuing stirling engine based solutions are Infinia and SunPower (not to be confused with its larger namesake in the PV industry).
Passive Solar Thermal - Solar Hot Water And Others
Generating power isn't the only way to utilise solar thermal energy of course - solar hot water is a very cheap and efficient way of replacing gas or electricity usage with solar energy. Solar hot water systems are in widespread use in Australia, with state and federal governments encouraging people to upgrade their home hot water systems to solar - almost cost free in some states. The New Zealand government is also encouraging the use of solar hot water systems.
Some larger scale uses of solar thermal hot water are being put in place by Abengoa in Texas and Colorado.
Solar hot water is in wide use in China as well, with the city of Rizhao becoming somewhat famous for achieving widespread takeup of the units.
An unusual variation of the direct capture of solar energy in the form of heat is from a Dutch company that has developed a "Road Energy System" that siphons heat from roads and parking lots to heat offices and homes.
And one final use of solar thermal power - it can keep your house warm, if your windows face the right way, and even better, have insulating glass that doesn't let the heat out again - which could help make your building energy positive.