Cased-Wellbore Compressed Air Storage for Renewable Energy

1 Review
Deployed by 1 company

Innovative technology as a geo-energy storage system

Page last modified
April 11 2024

The Cased-Wellbore Compressed Air Storage (CWCAS) technology is an advanced type of Compressed Air Energy Storage (CAES) process that is designed as a versatile and cost-effective renewable energy storage system. The system uses power from renewable sources to operate a compressor to compress ambient air. The high-pressure air is then stored inside a deep well(s), cased with high-grade steel. When there is a power demand, the compressed air is extracted from the well to generate power with an expander-generator.

Pros & Limitations
Versatile energy storage easily scalable, site independent and cost-effective
Rapidly increase the amount of reliable renewable energy in electricity supply systems
Storage of off-peak, excess, or irregular power from renewable energy sources - to reduce congestion and curtailment
Designed for grid, off-grid and behind-the-meter applications
Not site-specific; it can be utilized anywhere, including near existing transmission infrastructure
Integrates easily with solar and wind farms
Low environmental footprint compared to other energy storage technologies, such as batteries and pumped hydro storage
Safe and has a long life-cycle (20 – 25 years)
Mobilization, installation, and commissioning of a CWCAS facility is relatively fast and cost-efficient
CWCAS geo-ESS is a viable alternative to large-scale battery ESS
The CWCAS may not be suitable under certain operational conditions for UPS (Uninterrupted Power Supply management)
Specification Title Specification Description
Areas of Application
Wind and Solar Power Facilities | Remote Communities | Power for Industry, Mines| Re-purposing of Oil & Gas fields
Cased-Well Drilling and Construction | System Installation | Modelling & Project Development | R & D
A well is drilled and a high-grade steel casing is cemented into the wellbore, in a rock mass to a depth of 500 to 1,500 m.
Energy Capital Cost: CWCAS <$350/KWh vs. Battery Storage ~ $600/KWh
Storage of up to 10+ MWh per 1,000 m deep well.
Pressure class
7250+ PSI (50+ MPa)
A large well diameter is used at least 30 cm diameter casing. This provides a storage volume of 7 m3/100 m.
200 ºC (392 ºF)

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CleanTech Geomechanics Inc (CTG) is a Canadian company developing innovative technologies for geo-Energy Storage Systems (geo-ESS). CTG developed the concept of Cased-Wellbore Compressed Air Storage (CWCAS) for renewable energy storage. CWCAS is an advanced Compressed Air Energy Storage (CAES) process; and is a high-pressure, low-volume CAES process. CWCAS geo-ESS enhances the versatility and application of this energy storage approach.

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