The Economist

To make electricity from sunlight you can convert it directly, using a photovoltaic cell. Or you can use the heat of that sunlight to boil water, and then drive a turbine with the resulting steam. These are both established technologies. But there is, in principle, a third way: use heat directly, without steam or turbines. In this case, unlike a standard solar cell (which is sensitive to some frequencies of light, but not others), almost all of the incident energy is available for conversion. Yet unlike the boiling-water method, no messy mechanical processes are involved.