CARES - Compressed Air Renewable Energy Storage

Project of Common Interest in Cheshire, UK

Current Status of the Project

Purpose of Each Plant

As stated elsewhere, this project consists of two plants: one at 40MW, 200MWh and the other at 500MW, 2.5GWh. These will be in different Special Purpose Vehicles (SPVs), the first of which is Storelectric Cheshire Limited.


The purposes of the 40MW plant include:

  • Demonstrating the technology profitably;
  • Enabling the financing of the 500MW plant;
  • Providing balancing and ancillary services to the distribution grid.


The 500MW plant will do the same for the transmission grid.


Current Status

We have now completed the technical feasibility of the 40MW plant in conjunction with Costain and Fortum, the former undertaking static modelling including various sensitivity analyses, and the latter undertaking dynamic modelling using their industry-leading Apros system. To quote from the Executive Summary,













We are now raising funds for the FEED stage with the expectation of investment in taking this plant to “shovel ready” by mid 2019, for construction and commissioning by the end of 2020. “Shovel ready” includes:

  • Front End Engineering Design (FEED) to the point of letting contracts;
  • Obtaining planning permission from the local authority;
  • Obtaining a grid connection offer from the Distribution Network Operator (DNO – Scottish Power Energy Networks).

Once this is done, the same will be done for the larger plant, though the planning application will be through the Nationally Significant Infrastructure Projects (NSIP) process, and the grid connection offer will be from the Transmission Services Operator (TSO – National Grid).

We will undertake a public consultation with each planning application, details of which will be published either on this website or on the SPV’s website (to which this site will link) at the appropriate times.

“The system is robust and works well under all the sensitivities tested during this study. For the base case the round trip (i.e. grid-to-grid) efficiency calculated was 63.1%, with a range of 61% to 63.5% depending on findings of further study work (particularly the thermodynamic modelling of the caverns) and prevalent ambient conditions. The dynamic simulation conducted by Fortum show good correlation with the results of this study stating efficiencies of 62 to 64%. Previous works by Oswald Consultancy and Siemens put the efficiency at 62.3 and 62.7% respectively, albeit the process setup was marginally different.


“It is expected that further improvements to the efficiency should be achievable during the Front End Engineering Design Phase, with a close collaboration between the heat storage, compressor and expander suppliers.”




A 500+40MW adiabatic Compressed Air Renewable Energy Storage project in Cheshire, UK, providing large scale and long duration (5 hours) energy storage efficiently and without emissions



(+44) 7910 020 686


Project promoter: Storelectric Limited


Licensing the TES CAES technology from TES CAES Technology Limited


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