The PhARRE project (photovoltaic, self-supply, charging and power grid) is an exemplary local initiative headed by SyDEV, the public energy body for the Vendée département in western France, with the support of Bouygues Energies & Services. The aim is to trial new energy generation and storage possibilities, and potentially roll these solutions out in public buildings in the Vendée. PhARRE offers a response to three major ecological concerns for the coming years: reducing the impact of buildings’ energy consumption, storing green energy, and recycling or reusing electric vehicle (EV) batteries. What does it consist of? 200 m² of photovoltaic panels fitted on the roof of SyDEV’s head office providing 40,000 kWh a year, covering 15% of the building’s needs. A good way to reduce its carbon footprint while generating green energy. On top of that, to avoid losing the solar power surplus not used immediately and to keep it for use later on, this power is stored in used electric car batteries. These have lost 25% of their capacity and no longer meet the autonomy requirements of an electric vehicle, but can still be used as batteries for the building. A great example of the circular economy at work.