Some solar technology uses large crystals made out of silicon. When silicon is struck by sun light the electrons in the silicon crystal get up and move when exposed to light instead of just jiggling in place to make heat. The silicon turns a good portion of light energy into electricity, but it is expensive because big crystals are hard to grow. Fortunately, there have recently been major advancements in solar technology (like photovoltaic cells and solar thermal water heaters), making is more effective to gather solar power from the sun.
Americans can assume, at least in the Sunbelt regions of the southwestern United States including Tucson, Arizona, that every square yard of land exposed to direct sunlight will receive about 5 kilowatt-hours per day of solar energy roughly 4,200 watts of electricity.
According to the U.S. Energy Information Association, the average American home in 2008 used 11,040 kWh. This equals a daily usage of roughly 30 kWh. In other words, the average house would need 30 square yards of solar panels to completely eliminate their solar bill.
However, since Tucson Electric Power charges for electricity on a tiered, the more electricity one uses the more is costs, rating system solar electric power can greatly reduce one’s electrical bills by preventing their electric bill for reaching the next tier’s pricing range.