The higher a panel's efficiency, the more power it can produce. Most solar panels have cells that can convert 17-23% of the sunlight that hits them into usable solar energy. The most fundamental metric for sizing and evaluating any solar installation is its capacity. This measurement serves as the baseline figure for financial modeling, regulatory approval, and comparing different system. Solar energy can be harnessed two primary ways: photovoltaics (PVs) are semiconductors that generate electricity directly from sunlight, while solar thermal technologies use sunlight to heat water for domestic uses, to warm buildings, or heat fluids to drive electricity-generating turbines. Solar. Solar energy generation, measured in gigawatt-hours (GWh) versus installed solar capacity, measured in gigawatts (GW). Data source: Energy Institute - Statistical Review of World Energy (2025); IRENA (2025) – Learn more about this data Our World in Data is free and accessible for everyone. Help us. Enhance PVWatts ® with features tailored to your specific needs! We collaborate with companies, universities, and organizations to privately fund new capabilities or analyses. Your investment drives innovation while benefiting the broader energy community. That's the wattage; we have 100W, 200W, 300W solar panels, and so on. South. About 97% of home solar panels quoted in the second half of 2025 produce between 400 and 460 watts, based on thousands of quotes from the EnergySage Marketplace.