Neutral global warming potential target of electricity storage as threshold for greenhouse gas emission mitigation in buildings

Coupling photovoltaic (PV) systems with energy storage (ES) in buildings, enables to increase the building’s energy autonomy and the self-consumption of onsite renewables. ES increases nonetheless the life cycle environmental impact of the stored energy. As such, there exists a threshold where the GHG emission benefits of using ES start to compensate its own embedded and operational impact. In this study, a methodology to assess this neutral global warming potential target of ES is proposed, and is extended to the primary energy and its non-renewable part. The methodology is tested on a case study consisting of a feasibility project of a building located in Switzerland. When the surplus of renewable energy that cannot be used or stored directly is exportable to the grid, the operational benefits of the ES cannot balance anymore its embedded impact. In regards to market products, these neutral targets are tighter for GHG emissions than energy. Neutral targets are greatly affected by the characteristics of the grid mix supplying the building so the use of energy storage for the mitigation of GHG emissions in buildings may be efficient in Germany, but might be technologically more challenging with low-carbon French electricity.