抄録
In order to expand the use of renewable energy, a shift from "selling" to "self-consuming" of surplus electric energy generated by photovoltaic power generation (PV) is necessary. As for the means of the self-consumption, water heater with a hot water tank, which can store energy at relatively low cost as hot water, is attracting attention. Hybrid water heater, that has both an electric heat pump and a gas heat source, stores hot water to a relatively small tank compared to a simple electric heat pump water heater at less electric energy. Since it also has a gas heat source, there is no need to worry about running out of hot water even with a small tank. By combining a hybrid water heater and a storage battery system, an improvement of self power consumption ratio of PV energy is expected compared to the stand-alone usage of a hybrid water heater. This article reports the improvement result in an actual house. The self-consumption of PV energy used at the hybrid water heater was improved by 11.6 % in winter, 23.8 % in mid seasons, and 4.9 % in summer. Then the CO2 emission is reduced by 33 % a year.
