A single solar cell can produce up to 0. 7 watts of electric power when exposed to sunlight, making it crucial for designing an efficient solar energy system. Solar-cell efficiency is the portion of energy in sunlight that is converted into electricity by a solar cell. Photovoltaic modules, commonly known as solar panels, are a web that captures solar power to transform it into sustainable energy. Thus, a. Caution: Photovoltaic system performance predictions calculated by PVWatts ® include many inherent assumptions and uncertainties and do not reflect variations between PV technologies nor site-specific characteristics except as represented by PVWatts ® inputs.