A photovoltaic panel can convert sunlight directly into electricity. If one connects enough of them in a series-parallel arrangement called a solar array, they can provide about half of a home's annual electricity needs. The panels comprise specially treated electronic materials that when exposed to sunlight will give up electrons freely, and these can be made to flow through an external circuit to provide electricity. How much electrical energy (kWh) a solar system can collect is a function of where it sits on the earth's surface, which determines how much sunshine it receives. Ideally, a solar array should be situated so it faces south and tilted at an angle that allows it to collect the most energy available. That southern exposure should be as free of obstructions and shadowing as possible. This article takes a closer look at some of the practical concerns involved: tilt and location. (Contains 1 figure and 2 tables.)