With today’s cost of energy, it’s no wonder there is a renewed interest in generating electricity by means of the sun’s energy. This is not a new concept. The development of solar energy goes back more than 100 years. Early solar power plants produced steam from the heat of the sun, and the steam was used to drive machinery. In the same time frame, Henri Becquerel discovered the photovoltaic (PV) effect, which is the production of electricity directly from the sun. This early research was further enhanced by the work of Werner Siemens.
The key to PV technology is making it cost effective as a means to generate energy. This can be done by improving the efficiency of the PV cells to generate electricity from the sun as well as by decreasing the cost to manufacture the cell itself. As technology improves, the efficiency of PV technology has benefitted. Years ago, solar panels were about 5% efficient. Today, commercial modules using single-crystal silicon cells exceed 15% efficiency. Physics limits this efficiency to about 26%. Higher efficiencies to 40+% have been achieved in research applications using a high-concentration device requiring sophisticated tracking optics with a concentrating lens the size of a table and about one foot thick.