Battery energy storage systems for ancillary services in renewable energy communities

•Review of renewable energy community pilot projects for ancillary services.•Several ancillary services are available on European markets for storage.•Savona campus’s potential as a renewable energy community member.•User cooperation influences positively community costs and benefits.•Community aggregation with storage technologies enhance grid stability. Renewable Energy Communities can become relevant flexibility actors thanks to their capability of gathering under the same ecosystem, different energy assets, such as generation, and storage, and deferrable and controllable devices such as heavy appliances and computing assets. Particularly thanks to the integration of different energy storages RECs can therefore become a relevant grid operator. This document presents a review of storage and flexibility services alongside a quantitative methodology to analyze its benefits, using the Julia-based EnergyCommunity.jl package. The renewable energy community in Savona in collaboration with the University of Genova campus has been simulated to assert the battery energy storage systems potential. The study compares the outcomes of cooperative approaches with and without flexibility services to a scenario where users do not cooperate. The study concludes that storage systems can create new flexible instruments for the grid and a tool for citizens, which could make batteries financially viable. The study suggests that greater transparency and information on hourly energy sales and purchase prices would facilitate awareness among community members and stimulate discussion of technologies such as batteries to cover the most expensive nighttime periods for users.