Net energy metering (NEM) is a billing arrangement that credits solar customers for excess electricity they generate and return to the utility grid at the same rate they pay for grid consumption. This policy has been central to residential solar adoption across the United States since the 1990s, allowing homeowners to offset energy costs by exporting excess daytime generation. NEM structures vary significantly by state and utility, with some offering 1:1 retail rate crediting while others apply time-of-use rates or reduced compensation for exported energy.
Policy Variations
NEM 1.0 provided unlimited retail-rate credits for excess generation. NEM 2.0, introduced in California and adopted by other states, includes new charges and reduced export rates while preserving net metering benefits. NEM 3.0 further reduces export compensation and implements demand charges, requiring customers to carefully analyze system sizing before installation. Each state maintains distinct NEM policies affecting solar economics and payback periods.
System Design Impact
Net metering policies directly influence optimal solar array sizing, battery storage decisions, and financial return calculations. Systems designed under favorable NEM policies may operate without storage batteries, while those under restrictive policies often require battery backup to maximize self-consumption and minimize exported energy credits. Regular policy reviews ensure accurate cost projections and help customers understand compensation structures for their specific geographic location and utility provider.