Oxygen Storage Incorporated into the Allam Oxy-Fuel Power Cycle

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San Antonio, Texas
Project Term:
03/22/2021 - 06/21/2022

Critical Need:

Power plants equipped with carbon capture and storage (CCS) technologies can reduce the cost of net-zero carbon systems, but the addition of variable renewable energy (VRE) sources like wind and solar can make them difficult to design and operate while limiting their commercial potential. Increased cyclic operation of electricity generators could also reduce capacity factor and efficiency, increase operations and maintenance costs, and potentially increase CO2 emissions. Improving CCS processes and designs could enable a low-cost, net-zero carbon electricity system.

Project Innovation + Advantages:

Southwest Research Institute will apply energy storage to a natural gas, direct-fired supercritical carbon dioxide (sCO2) power generation cycle (Allam-Fetvedt cycle with near 100% carbon capture) by incorporating oxygen storage adjacent to the air separation unit (ASU). By operating the ASU at higher capacities when power from alternative energies is available (e.g., wind power at night or solar photovoltaic power during the day) and storing liquid oxygen (LOX), greater output from the power plant can be achieved during times of peak electricity demand. Using LOX’s vaporization cooling to reduce the compression power of CO2 needed for the power cycle can result in more savings. Because the ASU equipment is electrically driven, no change to the power block is required to produce up to 20% greater power plant output during peak demand.

Potential Impact:

Improvements in the design and processes of CCS-equipped plants in high VRE environments could dramatically reduce the cost of a net-zero carbon system. Benefits include:


Flexible CCS systems can enable the continued use of low-cost domestic fuel for electricity generation and increase the reliability of a deeply decarbonized electricity system.


Flexible CCS systems can achieve high CO2 capture rates from flue gas. For example, a power generator could be enabled to shift the times it exports electricity to the grid, allowing the power generator and CCS plant to operate under steady-state conditions and with reduced emissions.


Flexible CCS systems can reduce the cost of a net-zero carbon electricity system by providing dispatchable power to a high-VRE grid.


ARPA-E Program Director:
Dr. Jack Lewnard
Project Contact:
Dr. Jeffrey Moore
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