Optimal control of domestic hot water tanks in a housing cooperative - benefits for the grid

Energy communities (ECs) are emerging, and there is a need to understand how they will impact the distribution grid. One example of ECs in Norway today are housing cooperations with common assets such as thermal energy storage. This paper aims to quantity the benefit electric domestic hot water (DHW) tanks can give to a housing cooperative and the distribution grid. A real housing cooperative in Norway with six apartment blocks, rooftop PV and a common electric vehicle garage is investigated in three cases: a base case with no optimisation of the DHW tanks; individual optimisation of DHW tanks in each apartment block; and central optimisation of all DHW tanks in the housing cooperative as an EC with aggregated net metering. The apartment blocks, garage and DHW tanks have a peak electricity demand of 588 kWh/h, 156kWh/h, and 174 kWh/h, respectively. Compared to the base case, individual optimisation leads to a 4.4% reduction in peak demand. Central optimising leads to a 10.6% reduction in peak demand, and electricity costs are reduced by 2.6%, mainly due to a reduction in the demand charge electricity grid tariff.