Flexible Low Temperature CO2 Capture System, E-CACHYS™

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Project Term:
03/17/2021 - 12/16/2024

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:

Envergex aims to integrate a flexible, low-temperature CO2 capture system (E-CACHYSTM) into a natural gas combined cycle (NGCC) power plant, capable of operating in a high VRE environment, to attain a net-zero carbon electricity system. The technical approach is based on an innovative multi-phase sorbent technology for post-combustion capture of CO2 from flue gas. The hybrid sorbent technology, which consists of a regenerative sorbent and a novel heat exchange system for optimal energy recovery, seamlessly integrates into the NGCC architecture. The size of the proposed CCS system can align with the average capacity factor of the power plant, enabling constant operating conditions in the capture system and reducing overall plant operating expenses. Designing the next generation E-CACHYS™ for a 50% capacity factor could result in a cost of energy of $73/MWh if coupled with a 740 MW NGCC unit.

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. Enabling deep turndown of natural-gas fired plants at times of high VRE output will reduce fuel consumption and CO2 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. Srivats Srinivasachar
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