Impact of a solar domestic hot water demand-side management program on an electric utility and its customers

A methodology to assess the economic and environmental impacts of a large scale implementation of solar domestic hot water (SDHW) systems is developed. Energy, emission and demand reductions and their respective savings are quantified. It is shown that, on average, an SDHW system provides an energy reduction of about 3200 kWH, avoided emissions of about 2 tons and a capacity contribution of 0.7 kW to a typical Wisconsin utility that installs 5000 SDHW systems. The annual savings from these reductions to utility is $385,000, providing a return on an investment of over 20%. It is shown that, on average, a consumer will save $211 annually in hot water heating bills.