http://thefraserdomain.typepad.com/energy/2007/03/solarmission_so.html#comment-63664110

I think solar cogeneration is the best technology. Use trough concentration to boost solar PV to 40% efficiency, this happens at only 10 suns.

Then collect the heat for heating/cooling or to run a turbine generator on refrigerant.

I think road surface solar is better with heat tubing running through the asphalt. The heat collected could be used to run turbine generators. The efficiency would be less than cogeneration, but considering the huge road surface available it would still be a huge source of power.

The space on rooftops alone would provide more than enough power in sunny climes, a survey of San Diego rooftop solar locations proves it. Adding space over parking areas would power all serial plugin hybrids even if every internal combustion vehicle were converted.

Mass production of concentrating solar cogeneration would bring the cost down right around the current cost of wind power. The increased efficiency and the fact that only about 1/8th the amount of solar PV cells would be needed to provide twice the power compared to flat plate PV cells does the cost reduction.

Not to mention using the waste heat too. Total efficiency of electricity and heat collection could get up around 70% with this technology.

Then there is the other cogeneration element of algae grown in solar collectors, it sequesters cO2, produces biodiesel and powdered cellulose biofuel (that runs in solid oxide fuel cell/turbines), and recycles and cleans waste water. This can be combined with concentrating solar PV. the whole system mouted on rooftops or over parking lots.

Solar furnaces systems that concentrate sunlight with fields of mirrors can be used for manufacturing and recycling, with the waste heat stored in the molten silicon, glass, or metal (for instance) driving turbine generators to provide grid power after the sun goes down. molten heat storage salt or wax could be added to extend the power generation all night long. Another form of solar cogeneration.