Photovoltaic (PV) cells convert sunlight into electricity by using layers of semiconductor material that release electrons when struck by photons. Edmund Bequerel first noted the photoelectric effect in 1839, and Albert Einstein later described its nature. In the 1960s, the space industry began using solar technology to power spacecraft. Solar panels work by sunlight creating direct current that is converted to alternating current and connected to existing electrical systems. While initial installation costs may be high and solar panels do not work at night, solar power has advantages in being renewable, reducing fossil fuel use, and stimulating economic growth in green jobs.