There are several free tools available that can help estimate solar power generation and forecast system performance. Many of these platforms use historical weather data, solar irradiation levels, and system configuration details to provide fairly accurate energy production estimates. One widely used option is the PVWatts Calculator developed by National Renewable Energy Laboratory. It allows you to enter your location, system size, panel orientation, and other parameters to estimate annual and monthly solar energy production. Another popular platform is PVGIS provided by European Commission, which offers detailed solar radiation data and system performance calculations for many regions around the world. These tools are very helpful during the planning stage because they allow you to compare different system sizes, panel angles, and locations before installation. While they provide good estimates, it’s still important to have a professional system design done to account for factors like shading, roof layout, and local electrical requirements. Overall, free solar forecasting platforms are a great starting point for understanding how much energy a potential solar system could generate.