[1] The Clean Energy Standard Act of 2012 defines «clean» electricity as «electricity generated at a facility placed in service after 1991 using
renewable energy, qualified
renewable biomass, natural gas, hydropower, nuclear power, or qualified
waste - to - energy; and electricity generated at a facility placed in service after enactment that uses qualified combined heat and power (CHP), [which] generates electricity with a carbon - intensity lower than 0.82 metric tons per megawatt - hour (the equivalent of new supercritical coal), or [electricity generated] as a result of qualified efficiency improvements or capacity additions at existing nuclear or hydropower facilities -LSB-; or] electricity generated at a facility that captures and
stores its carbon dioxide emissions.»
The preference for grid - connected systems not only enhances grid reliability by supplementing grid power with these new
renewable energy sources, but taps into any excess solar power that is not used on - site that would otherwise be
wasted if not
stored in a portable battery.