Even the most optimistic reading has these "rain panels" well under 1W/m^2. For comparison, peak solar irradiance is something like 1400W/m^2. This webpage has

Even the most optimistic reading has these "rain panels" well under 1W/m^2. For comparison, peak solar irradiance is something like 1400W/m^2. This webpage has already burned more energy than that panel will ever produce.