Sizing Energy Storage in Electricity Grids Containing Flexible Loads

Abstract

Flexible loads such as EV chargers and heat pumps have the potential to reduce the amount of energy storage required to handle local power imbalances. However, when sizing energy storage these loads are often neglected. Thereby it is unclear how intelligently controlled flexible loads influence energy storage sizing. Therefore, this paper presents an empirical study into the effect of controlling four different classes of flexible loads on energy storage sizing, under which fall existing technologies such as EV chargers, heat pumps and white-goods. We use a Profile Steering control strategy to minimize the power imbalance over the considered period. Furthermore, we use parameter sweeps to investigate the influences of load availability and load demand on the energy storage sizing, and visualize the energy storage reduction with heat maps. The results show that significant energy storage sizing reductions are possible if flexible loads are considered, including a reduction in capacity of more than 60%. Furthermore, if flexible loads can also supply their buffered power to the local microgrid (such as with V2G applications), the need for energy storage is almost completely removed. We conclude that it is important to consider local flexible devices when sizing storage in order to avoid over-dimensioning.

Keywords: electricity grid flexibility, energy storage sizing, flexible loads, Electrical Vehicle charging, heat pumps