Green CAES is Storelectric's adiabatic Compressed Air Energy Storage technology. The cycle runs in two phases:

1) On charge, compressors use surplus renewable energy to push ambient air into the cavern at pressure; the heat this generates, which conventional CAES wastes, is captured and held in a thermal storage system.

2) On discharge, air is drawn back out of the cavern, reheated using that stored heat rather than burned fuel, and expanded through a turbine to generate clean electricity.

This removes the gas-fired reheat step used in the conventional CAES model which Green CAES builds on. The conventional process has a round-trip efficiency of 42–54%. Green CAES replaces the combustion step with thermal storage, cutting emissions at the point of generation, with an improved round-trip efficiency of up to 70%.

The technology is built from standard, multi-sourced industrial equipment rather than bespoke components, which lowers build cost, improves reliability, and allows operation across a wide range of cavern pressures.

Storelectric's project, TeesCAES, is set to demonstrate this at commercial scale. TeesCAES is the sole CAES project provisionally selected for support under window one of Ofgem's LDES Cap and Floor scheme.