On average, a well-designed and properly installed 20kW solar system can generate between 2,000 to 2,500 kilowatt-hours (kWh) of electricity per month, depending on the location and time of year. This translates to an annual energy production of 24,000 to 30,000 kWh. . If we know both the solar panel size and peak sun hours at our location, we can calculate how many kilowatts does a solar panel produce per day using this equation: Daily kWh Production = Solar Panel Wattage × Peak Sun Hours × 0. 75 / 1000 As you can see, the larger the panels and the sunnier the. . A 20 kilowatt (kW) solar panel system can power most homes while significantly reducing monthly utility costs. It's easy to use, requires just a few inputs, and provides accurate projections that can help you make informed decisions about your energy needs and return on investment (ROI). household's 900 kWh/month consumption, you typically need 12–18. . 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. For example, PV modules with better. .