A photovoltaic battery can convert solar light into usable energy.
By 1958, Hoffman Electronics produced photovoltaic cells that were 9 percent efficient, and then the following year those cells were used to power Vanguard I, the first satellite to use PV technology for power.
Stored water is then pumped to an internal header tank using a pump powered by a photovoltaic (solar electric) panel.
While its share of meeting the nation's energy needs is currently small, the number of photovoltaic panel installations grew 40 percent in 2009, according to data from the Interstate Renewable Energy Council.
Confused about whether to lag the boiler, insulate the loft or re-tile the whole roof in photovoltaic cells?