Does bulk electricity storage assist wind and solar in replacing dispatchable power production?

Abstract

This paper discusses the impact of bulk electric storage on the production from dispatchable power plants for rising variable renewable electricity shares. Two complementary optimization frameworks are used to represent power systems with a varying degree of complexity. The corresponding models approximate the wholesale electricity market, combined with the rational retirement of dispatchable capacity. Two different generic storage technologies are introduced exogenously to assess their impact on the system.The analysis covers two countries: France, where the power supply's large nuclear share allows for the discussion of storage impact on a single generator type; and Germany, whose diverse power supply structure enables storage interactions with multiple electricity generators. In the most general case, additional storage capacity increases dispatchable power production (e.g. nuclear, coal) for small wind and solar shares, i.e. it compensates the replacement induced by renewable energies. For larger variable renewable electricity volumes, it actively contributes to dispatchable power replacement. In a diverse power system, this results in storage-induced sequential mutual replacements of power generation from different plant types, as wind and solar capacities are increased.This mechanism is strongly dependent on the technical parameters of the storage assets. As a result, the impact of different storage types can have opposite signs under certain circumstances. The influence of CO2 emission prices, wind and solar profile shapes, and power plant ramping costs is discussed.