ENHANCING GRID FLEXIBILITY WITH VIRTUAL POWER PLANTS: A STUDY ON THE INTEGRATION OF RESIDENTIAL WATER HEATERS AND HEAT PUMPS IN THE BELGIAN POWER SYSTEM

Within the framework of the Paris Agreement, the global energy transition towards 2050 and beyond seeks to achieve flexible energy country systems, free of CO2 emissions, waste and with a minimum system cost. Insights from the adequacy and flexibility study, carried out by the Electricity Transmission System operator in Belgium, highlight the need for decentralized flexibility solutions in the Belgian electricity grid to adapt it to the variability
of renewable energy sources and benefit from the increase of residential and industrial appliances. A key lever to achieve this is by leveraging residential electric water heaters and heat pumps water heaters as a decentralized storage and demand response resource for grid flexibility. This study aims to asses the available flexibility of a fleet of these technologies integrated into a Virtual Power Plant. The fleet of water heaters is modeled using Dispa-SET, a unit commitment and optimal dispatch model, applied to the case of Belgium. The analysis is carried out for the current power system and also with future plausible scenarios where the system counts with higher shares of variable renewable energy and the phase-out of nuclear power. The unit commitment and optimal dispatch model furthermore allows to simulate the participation of the Virtual Power Plant through the Boundary Sector concept, which serves as an interface to represent interactions between the power and non-power sectors. This innovative approach allows the aggregated water heaters to be integrated as a flexible resource capable of
providing demand-side management and cross-sectoral energy services. The results show a significant increase in the potential for the integration of renewable sources, and consequently a reduction in curtailment in a range varying between 6.72% and 79.37% depending on the scenario. On the other hand, the congestion analysis shows needs of increasing the net transfer capacity between Belgium and the neighboring countries.