Impact of storage systems participating in energy markets on distribution grids

This paper studies the impact of a battery storage system connected to a distribution source substation and participating in the Day-Ahead (DA) or Frequency Containment Reserve (FCR) energy markets. The supply of these products results in charge/discharge power profiles added to the natural profiles of the source substations to which these storage systems are connected. These profiles are uncorrelated with the electrical uses initially present in the connection zone and can therefore lead to unexpected technical constraints. This paper thus quantifies the impact of storage facilities operating on wholesale markets and connected to the distribution grid through a selection of metrics. In particular, the number of tap changes of the on-load tap changer is significantly impacted by the participation of the source-connected storage operator in the DA market, which is less the case with FCR.