PV Trends:
In a laboratory some PV cells have been able to reach efficiencies up to 31%. These are to expensive to be used economically (Ashley, 1989).
PV systems have grown in popularity for people who are already connected to the electrical grid. The growth of grid connected customers is 25-30% per year (Fies, 2001).
The Public Utility Regulatory Policy Act (Section 210) requires utility companies to buy power from renewable energy producers. In a grid tied system the homeowner is the producer so the power company has to buy the power (Stone, 2001).