A 100W solar panel converts approximately 100 watts, under optimal conditions, which translates to 0. 1 kilowatts per hour of electricity generated. In ideal situations, it can yield around 300-400 watt-hours daily, depending on sunlight exposure and geographical location. Efficiency, in combination with latitude and weather, determine the energy output of a solar system. But pay attention to this: this "100W" description is the panel's maximum rating, often measured under Standard Test. A 100-watt solar panel is a small-scale energy magician. Due to the many advances in photovoltaic technology over the last decade, the average panel conversion efficiency has increased from 15% to over 24%. Typical total efficiency ranges 75–90%. Increasing panel count or choosing higher wattage.