• Leaderboard rankings are determined by the amount of CO2 each user's renewable systems saved during the previous and current week and the amount spent to save each ton—with CO2 savings being given slightly more importance.
• Every megawatt hour (MWh) your renewable systems generate equals about 0.7 metric tons of CO2 saved. This is the amount of CO2 produced by a month of electricity use in a typical U.S. home using fossil fuels.
• The weekly (or daily) cost of a system is its total installation cost divided evenly by the number of weeks (or days) in the system's 30-year lifespan.
• Cost per ton is the portion of the cost of all systems in all locations during a given production period divided by the number of tons of CO2 saved.
