The impact of scheduling appliances and rate structure on bill savings for net-zero energy communities: Application to West Village

Abstract

This paper investigates the financial incentives of load shifting under a time-of-use rate and Net Energy Metering pertaining to the solar net-zero energy apartment community, West Village in Davis, California. By “smart-scheduling” the electricity and domestic hot water demand of the dishwasher, clothes washer, dryer, sinks and showers solely to off-peak periods, the peak demand is reduced by 18%, the part-peak demand by 32% and the off-peak demand increased by 12%. With this shifted schedule customers accrue twice as many credits as they would receive under a non-shifted schedule with the same time-of-use rate, totaling to $2975 of “free” electricity per year for one 12unit building. But, under current rates smart-scheduling is found to be worthwhile only during the months from May through October, when 96% of the credits are accumulated. If the rate schedule is altered to include peak-periods during the winter months, the credit savings will double again in value. These comparisons are prepared using two photovoltaic simulation programs (PolySun by Vela Solaris and System Advisory Model by the National Renewable Energy Laboratory) and for apartments using an electric heater and a heat pump for domestic hot water. By quantifying these savings, PV generating customers are informed that a time-of-use rate can benefit them significantly, especially if the surplus generation is maximized and sold to the grid during peak day time hours. With this information, housing developers can create effective incentives for residents, and utility companies, policy makers and designers of smart-scheduling household appliances can encourage a more reliable, clean and economical national grid.