In Hawaii, like most U.S. states, households installing rooftop solar photovoltaic (PV) systems receive special pricing under net-metering agreements. These agreements allow households with rooftop solar to buy and sell electricity at the retail rate, effectively using the larger grid to store surplus generation from their panels during sunny times and return it when the sun isn’t shining. If a household generates more electricity than it consumes over the course of a month, it obtains a credit that rolls over for use in future months. Net generation supplied to the grid in excess of that consumed over the course of a full year is forfeited to the utility.