The impacts of solar water heating in low-income households on the distribution utility’s active, reactive and apparent power demands

In Brazilian low-income households, water-heating requirements are typically met by electrical showerheads. On average, 73.1% of all residential units in the country are equipped with these resistance-heating devices, with nominal powers ranging from 3 to 8 kW. This situation imposes a considerable burden on the electricity utility companies, since electrical showerheads typically represent the highest load but the lowest utilization (load factor) in a residential consumer unit. Furthermore, typical utilization times coincide with, and contribute to, the electrical power demand peaks in Brazil, rendering these low-cost, high-power electrical devices a high-cost consumer for the electrical system to cater for. For low-income residential consumers, electricity tariffs are subsidized, and utilities must therefore make a considerable investment in infrastructure for a limited return. In this paper we analyze the impacts of solar water heating in low-income households on the distribution utility active, reactive and apparent power demands. We have monitored a statistically representative group of low-income residences equipped with a compact domestic solar water heater in Florianopolis – Brazil for 1 year. We show that in comparison with identical residential units using electrical showerheads, with the adoption of solar water heating the reductions in the active, reactive and apparent power demands on the distribution utility were 49%, 29% and 49% respectively. 2011 Elsevier Ltd. All rights reserved