The basic unit of all solar electric technology is the photovoltaic (PV) cell.
Solar electric (PV) and solar thermal (ST) are proving technologies, however; the primary industry focus currently is on grid-tied solar electric photovoltaic (PV) power, with solar thermal (ST) power accorded a secondary focus. The reason for taking this approach is that, as presently constituted, the U.S. solar market is built primarily on sales of PV systems.
The solar power market cannot be properly understood without reference to the overall U.S. electricity market, which is thoroughly dominated by coal, natural gas, and nuclear power. Thus the status quo electricity market based on non-renewable energy power must be taken into scope.