Curious about the differences between solar thermal and solar photovoltaic? I was. Check out this explanation from the US Energy Information Administration:

Solar energy can be converted to electricity in two ways:

• Photovoltaic (PV devices) or “solar cells” change sunlight directly into electricity. Individual PV cells are grouped into panels and arrays of panels that can be used in a wide range of applications ranging from single small cells that charge calculator and watch batteries, to systems that power single homes, to large power plants covering many acres.

• Concentrating Solar Power Plants generate electricity by using the heat from solar thermal collectors to heat a fluid which produces steam that is used to power the generator. Out of the 11 known concentrating solar power generating units operating in the United States at the end of 2008, 9 of these are in California, 1 in Arizona, and 1 in Nevada.

EIA’s Energy Kids page on solar continues the explanation in language we can easily understand!