Solar thermal stores heat from the sun into molten salt to be used as needed to generate power through conventional steam turbines. Thus, it can generate power any time day or night, even when the sun isn’t shining. This is a zero emissions process and the salt itself is completely non-toxic.
Renewable Energy World has an fact-filled article about how solar thermal works written by the director of development at SolarReserve, who have a 1200 acre solar thermal plant. Their website has a wealth of information.