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Point Source Carbon Capture from Power Generation Sources


FEED Studies | Engineering-Scale Testing | Laboratory- and Bench-Scale Testing


Process diagram of carbon capture and compression in an NGCC plant.
Process diagram of carbon capture and compression in an NGCC plant.

Point source capture (PSC) in fossil fuel-based power production separates CO2 emissions from a power plant’s flue gas or syngas stream to prevent its release into the atmosphere. The captured CO2 is durably stored or converted to a long-lived product, resulting in an overall reduction in CO2 emissions. In conventional fossil fuel-fired power plants, a fossil fuel such as natural gas is combusted with air to generate thermal energy, which is converted to electricity. Combined cycle gas plants are a type of natural gas power plant consisting of a simple cycle gas plant in combination with a steam engine, using both heat and steam to generate electricity. In a natural gas combined cycle (NGCC) plant, the heat generated from combusting natural gas is expanded through a gas turbine, generating electricity, while waste heat from the gas turbine is used to generate steam, which then powers a second turbine, generating additional electricity. Of the 4 trillion kilowatt-hours of electricity generated in the United States in 2020, approximately 40% was from natural gas (2021, EIA)i. With 60% of the total U.S. energy consumption from fossil fuels, deployment of point source capture technologies in power production is vital to reduce CO2 emissionsi. One principal challenge in carbon capture from fossil fuel power generation is cost-effectively separating the relatively low concentration of CO2 from the other flue gas constituents that generally are detrimental to separation materials, capture systems, materials of construction, and process and plant efficiency. Although flue gases from NGCC plants typically contain approximately 4 to 5% CO2 by volume (compared to 12 to 15% in coal-fired flue gas), natural gas is less carbon-intensive than other fossil fuelsii.

The U.S. Department of Energy/National Energy Technology Laboratory’s (DOE/NETL) PSC Program has identified and advanced carbon capture technologies since 2001, with the goal of decreasing the cost and improving the efficiency of carbon capture systems that can be installed on existing or new fossil fuel-fired power plants. The program sponsors technology development ranging in scale from laboratory projects using simulated gases, to engineering-scale projects (up to 12 megawatt-electric [MWe]) testing technologies at operating power plants on actual flue gas, to front-end engineering and design (FEED) studies focusing on carbon capture systems integrated into specific operating power plants combined with long duration carbon storage or conversion of the CO2 into long lived products in preparation for future commercial demonstration. The program is further advancing the development of cost-effective carbon capture technologies, with a focus on capturing at least 95% of the total CO2 emissions from point sources and generating CO2 suitable for geologic storage or conversion/utilization.


FEED Studies for Carbon Capture Systems at Coal and Natural Gas Plants 

To facilitate wide-scale deployment of carbon capture systems, the Carbon Capture Program supports the execution of FEED studies to provide estimates of the capital and operating costs for installing commercial-scale, advanced post-combustion CO2 capture technologies that have achieved a Technology Readiness Level (TRL) of at least 6 at new or existing power plants. FEED studies incorporate knowledge gained from feasibility studies and completed field-testing of the specific technologies to define a project scope of work, design basis identifying host site characteristics and permitting requirements to initiate construction, material purchasing and construction schedules, and an engineering design package resulting in preparation of a capital cost estimate including $/tonne net CO2 captured. The FEED studies also examine the benefits and economics of integrating CO2 captured from a power station directly into an existing CO2 pipeline network and possibly direct use by end-users.

3D design for 550-MWe capture plant with Linde-BASF post-combustion CO<sub>2</sub> capture technology developed in pre-FEED study.
3D design for 550-MWe capture plant with Linde-BASF post-combustion CO2 capture technology developed in pre-FEED study.

Engineering-Scale Testing of Carbon Capture Technologies

The Carbon Capture Program also supports engineering-scale testing (i.e., up to 12 MWe or 200 tonnes CO2/day) of advanced post-combustion CO2 capture technologies under actual flue gas conditions. Engineering-scale testing of carbon capture technologies can be performed at carbon capture test centers or by means of purpose-built pilots installed at power plant facilities. Testing under continuous steady-state operation, as well as off-load plant conditions, provides performance data necessary for further process scale-up. Results from field-test campaigns provide critical information for a subsequent FEED evaluation.

Calpine’s Los Medanos Energy Center, a commercially dispatched NGCC power plant; host site for engineering-scale testing of ION Clean Energy’s solvent technology.
Calpine’s Los Medanos Energy Center, a commercially dispatched NGCC power plant; host site for engineering-scale testing of ION Clean Energy’s solvent technology.

 

Carbon Capture Test Centers

National Carbon Capture Center
National Carbon Capture Center.

The National Carbon Capture Center (NCCC), DOE’s primary carbon capture research facility operated and managed by Southern Company, provides a platform for testing and evaluating third-party technologies at bench- and engineering-scale, bridging the gap between laboratory research and large-scale demonstrations. The NCCC infrastructure includes multiple, adaptable test units, offering the flexibility of testing multiple technologies simultaneously under power generation process conditions over a range of scenarios that will enable evaluation of the efficiency, environmental performance, and economic viability of fossil fuel-fired power generation processes with CO₂ capture. After 10 years of successful technology development for carbon capture from coal-fired power systems, the NCCC has expanded its post-combustion test capabilities to include natural gas-derived flue gas from a natural gas boiler. The boiler produces flue gas that is representative of that from a commercial NGCC power plant.

In addition to supporting the testing of integrated CO2 capture systems at operating power plants, NETL partners with Technology Centre Mongstad (TCM) in Norway, the world’s largest open access test center for carbon capture technologies, to conduct engineering-scale test campaigns under actual flue gas conditions. TCM’s facility consists of two post-combustion capture plants (one based on chilled ammonia technology and one based on amine technology) designed to test solvent-based technologies using actual flue gas - at the equivalent of approximately 12 MWe - sourced from an on-site natural gas-fired combined heat and power (CHP) plant or the residue fluid catalytic cracking (RFCC) flue gas of the Equinor refinery. The TCM facility also consists of a module site for testing emerging carbon capture technologies.

Technology Centre Mongstad
Technology Centre Mongstad.
Wyoming Integrated Test Center
Wyoming Integrated Test Center.

The Wyoming Integrated Test Center (ITC), located at Basin Electric Power Cooperative’s Dry Fork Station in Gillette, Wyoming, is also utilized by NETL for testing of post-combustion carbon capture and utilization technologies. The ITC is focused on larger scales of testing to compliment the testing performed at NCCC, and features five small sites and one large site, utilizing up to 20 MW equivalent of coal-based flue gas from the power plant.


Laboratory- and Bench-Scale Testing of Carbon Capture Materials and Processes

Research and development (R&D) of advanced materials and highly efficient components is critical in developing carbon capture technologies that economically capture at least 95% of CO2 from NGCC flue gases with 95% CO2 purity. Hybrid technologies combine different types of materials (e.g., sorbent-membrane) into one system to achieve higher efficiency while minimizing the energy penalty. Novel concepts involve innovative solutions for CO2 capture, such as cryogenic separation or electrochemical processes, or additive manufacturing of materials to enhance thermodynamic operations and reduce equipment size. Enabling technologies comprise topics, such as additives for solvent viscosity reduction, solvent aerosol emissions mitigation, and anti-corrosion coatings, and can potentially be applied to an entire class of materials. In addition to materials, the PSC Program also conducts R&D on advanced processes and process intensification techniques to be used in tandem with the advanced materials to provide the most optimized carbon capture systems.

Dual phase membranes for post-combustion CO2 capture
Dual phase membranes for post-combustion CO2 capture.
Advanced structured adsorbents for CO2 capture
Advanced structured adsorbents for CO2 capture.
Electrochemically mediated amine regeneration process.
Electrochemically mediated amine regeneration process.

i U.S. Energy Information Administration. Electricity in the United States.
https://www.eia.gov/energyexplained/electricity/electricity-in-the-us.php

ii U.S. Energy Information Administration. Today in Energy.
https://www.eia.gov/todayinenergy/detail.php?id=31012