Green CAES™

Compressed Air Energy Storage (CAES™) is a cost-effective, efficient and proven technology in the production of clean grid-scale electricity.

CAES™ solutions tackle grid instability, allowing sovereign nations to move away from interconnectors and achieve energy independence.


When intermittent renewables do not produce enough power for the demand, traditional power plants have to meet that demand.

Storing energy when it is abundant is the solution

Currently, there are only two technologies that have proven references of over 30 years in Energy Storage. 

These are Pumped Hydro Energy Storage (PHES) and Compressed Air Energy Storage (CAES).

Other technologies are developing but are severely hampered by longevity issues, size and duration restrictions.

CAES™ IS A proven Energy storage solution

Our technology has been proven; CAES has been in operation since 1978 in Huntorf in Germany, and since 1992 in McIntosh, Alabama, USA. Both plants store compressed air in underground salt caverns, ready to be expanded when required.

However, they both regenerate electricity by feeding it into a gas-fired power station.

Our Green CAES technology uses a Thermal Energy Management & Storage system to recoup lost heat from the compression process and reuse it in the power cycle.

Thus eliminating Fossil fuels from the process, decreasing costs significantly, and improving plant efficiency.

Green CAES can utilise the existing infrastructure of the fossil fuel industry to produce peaking or baseload energy; fossil fuel-free and with zero emissions.

Hydrogen & CAES


Our Green CAES technology provides a perfect solution for enabling renewables to power the grid with zero emissions, whilst our Hydrogen CAES™ can increase plant’s efficiencies and lower their operating costs during the transition away from fossil fuels to a Hydrogen economy.

For a truly flexible solution with the lowest costs and highest efficiencies, we have also developed a Hybrid system which can switch between Green CAES™ and Hydrogen CAES™ – burning fuels only when energy stores are depleted.


Electrolysis (and fuel/chemical synthesis) does not operate as efficiently when powered intermittently. By including CAES in a renewables & hydrogen project, we can deliver near-baseload energy to the electrolysers, as well as high-value services to the electricity grid, and can do so very cost-effectively.



  • Zero emission fossil-fuel free peaking or baseload power
  • Bulk energy storage 20MW to multi-GW power, and 4 hours to multi-day duration
  • Maximized flexibility providing load shifting, grid balancing, ancillary services and T&D deferral solutions
  • 24-hour voltage support, emergency power, black start, and power quality conditioning
  • Allows the replacement of fossil fuel generation with low cost renewable energy, cutting or eliminating emissions
  • Also flexible consumption, providing Demand Turn-Up and related balancing services
  • Renewable energy on demand at a lower cost than diesel / OCGT power
  • Co-location with output cables for major renewable generation or interconnectors reduces grid connection capital costs and grid access charges, and maximises revenues.
  • Time shift generation to maximise project economics and provide risk mitigation during triads
  • Eliminate curtailment of low marginal cost renewable energy at times of low demand
  • Baseload or peaking plant designs sized to cover peak demand periods
  • Electrical independence for islands, micro-grids, and off-grid locations
  • Co-location with renewables also enables the generator to avoid grid access charges on its output energy, storage to avoid them on charging energy and storage to avoid capital costs of grid connections
  • New transmission and distribution lines, substation capacity and other assets have long lead time, are expensive, and challenging to permit
  • Maximise existing T&D capacity by utilising capacity bringing power through transmission bottlenecks to charge during off-peak times
  • During peak demand times, inject electricity from storage after the T&D bottleneck, to supply market on the load side
  • Co-location with renewables benefits grids by greatly reducing reinforcement and adding real inertia 24/7
  • Emissions-free (Adiabatic) Green CAES ™ can be installed in densely populated urban areas as it uses no hazardous substances
  • Provides flexible generation and reliable back-up power for critical areas and infrastructure
  • Repurpose existing coal plants by leveraging location and existing infrastructure
  • Re-purpose existing CCGT/OCGT by leveraging location and existing infrastructure
  • Such re-purposing gives new life to otherwise stranded assets by adding revenue streams, reducing emissions and (as price volatility increases) reducing operational costs
  • Co location of storage with renewable generators allows better use of under-utilised T&D infrastructure
  • Repurposing existing salt caverns currently used for natural gas storage for improved economics
  • Repurposing of other underground storage assets such as aquifers, depleted hydrocarbon fields, disused mines, porous inclusions.