Gravitricity Ltd, Development of Hybrid Mechanical and Compressed Air Energy Storage System

This is a proposal to develop a novel technology based on a combination of using gravity and compressed air

for grid-connected electrical energy storage at a scale from 100kW to 50MW peak power and from 250kWh to

10MWh energy per cycle. This will fill a technology gap between small-scale relatively short-life storage devices

like flywheels and batteries, and inherently large scale systems like pumped storage. It also has major

advantages including rapid response (<2s to full power) and high energy efficiency (>90% round-trip efficiency)

with no cyclic deterioration (performance is not affected by number of storage cycles or by part-loading).

The project will include engineering work to develop all aspects of the technology (including a methodology to

vertically drill holes up to a km deep and 5m in diameter) alongside parallel commercial work to ensure the

technical offering will suit the emerging demand for energy storage on power grids. The project will output fully

costed plans for a proof-of-concept prototype deployment to be deployed within 3-5 years.