**The Allam Cycle (TAC)**, also known as the Allam-Fetvedt Cycle, is a power generation process that uses supercritical carbon dioxide (sCO2) as a working fluid in a high-pressure, low-pressure-ratio, oxy-fuel Brayton cycle to convert carbonaceous fuels into electricity with near-zero carbon emissions. TAC captures nearly all CO2 and water produced during combustion, making it a promising technology for clean energy production. TAC achieves high efficiency (up to 60% for natural gas) by recycling supercritical CO2 to control combustion temperatures and using a recuperated system to minimize energy losses. The captured CO2 is pipeline-ready for sequestration or utilization, and the cycle produces liquid water as a byproduct, potentially eliminating water usage if air cooling is employed. **Key TAC Features:** - **Oxy-Fuel Combustion**: Burns fuel (natural gas or syngas) with pure oxygen, producing primarily CO2 and water, simplifying emissions handling. - **Supercritical CO2**: Uses high-pressure sCO2 as the working fluid, which is compressed, heated, and expanded in a turbine, achieving high thermal efficiency. - **Carbon Capture**: Inherently captures nearly 100% of CO2 emissions without additional costly equipment, making it cost-competitive with traditional gas plants. - **Applications**: Suitable for natural gas, coal-derived syngas, or biomass, with potential integration into processes like LNG regasification or ammonia production. **How It Works (Simplified):** 1. **Combustion**: Fuel is burned with oxygen in a combustor with recycled sCO2 to control temperature, producing a high-pressure CO2-rich exhaust. 2. **Turbine Expansion**: The exhaust drives a turbine, generating electricity. 3. **Heat Recovery**: Exhaust heat is recovered in a regenerator to preheat the recycled sCO2. 4. **CO2 Processing**: The exhaust is cooled, water is separated, and high-purity CO2 is either recycled back to the combustor or extracted for sequestration/utilization. 5. **Compression and Pumping**: The recycled CO2 is compressed and pumped to high pressure, maintaining the cycle’s efficiency. **Companies Working on the Allam Cycle:** 1. **NET Power**: - A key developer of the Allam Cycle, owned by 8 Rivers Capital, Exelon Generation, and CB&I (now part of McDermott). - Operates a 50 MWth demonstration plant in La Porte, Texas, which successfully synchronized to the ERCOT grid in 2021, validating the technology.en.wikipedia.orgsciencedirect.com - Plans to develop a 300 MWe commercial natural gas plant, with potential commissioning as early as 2025 in the UK. powermag.com 2. **8 Rivers Capital**: - The primary innovator behind the Allam-Fetvedt Cycle, focusing on its commercialization and global deployment. - Collaborating with Sembcorp Energy UK for the 300 MW Whitetail Clean Energy project at Teesside, UK, aims to capture 800,000 tons of CO2 annually. 3. **Sembcorp Industries**: - Through its subsidiary Sembcorp Energy UK, it is partnering with 8 Rivers to develop the UK’s first Allam Cycle-based power plant at the Wilton International site. powermag.com 4. **Toshiba**: - Developed the turbine for NET Power’s La Porte demonstration plant, addressing challenges like operating in a supercritical CO2 environment with potential carbonic acid formation. petro-online.com 5. **Other Stakeholders**: - **Exelon, McDermott, and Occidental Low Carbon Ventures**: These companies are joint investors in NET Power, supporting its development and commercialization efforts. powermag.com - Institutions and engineering firms involved in modeling and optimizing TAC, as seen in studies by Scaccabarozzi et al. and Li et al., mdpi.com **Additional Notes:** - TAC has been recognized as a breakthrough technology (e.g., by MIT Technology Review in 2018) due to its potential to provide cost-competitive, emissions-free electricity. - Challenges include the need for robust CO2 pipeline infrastructure and high initial costs for components like the air separation unit (ASU). atlanticcouncil.org - TAC’s efficiency ranges from 48–60% for natural gas and 38–51% for syngas, depending on configuration and fuel. sciencedirect.com ![[Picture1.jpg]]) [NET Power’s First Allam Cycle 300-MW Gas-Fired Project Will Be Built in Texas](https://www.powermag.com/net-powers-first-allam-cycle-300-mw-gas-fired-project-will-be-built-in-texas/) [[NetPower]] **Simple TAC Schematic:** ![[Picture2.jpg|720]] **Allam Cycle 2025 Commercialization Status** **Current Status** **1. Demonstration Plant Success** - **NET Power’s 50 MWth Facility (La Porte, Texas)**: - Operational since 2018, synchronized to the TX ERCOT grid in November 2021. - Uses natural gas, near-100% CO2 capture and high efficiency (up to 60% LHV). - Validates core components (sCO2 turbine, combustor) designed by Toshiba, confirming technical feasibility through long-duration testing. **2. Planned Commercial-Scale Projects** - **United States**: - **Odessa, Texas (300 MWe, Natural Gas)**: - Announced in November 2022 by NET Power, to be built at an Occidental-hosted site. - Described as the “serial number one” commercial project, targeting low-cost, zero-emissions power with inherent CO2 capture. - Construction planned for 2023, with power production targeted for 2025. - **Status in 2025**: No updates confirm operation. Delays in final investment decisions (FID), supply chain issues, or regulatory approvals may have impacted the 2025 timeline. Front-end engineering design (FEED) studies were underway in 2022, suggesting late-stage development or early construction. - **Coyote Solar & Power Project (Southwest Colorado, 280 MWe)**: - Announced in April 2021 by 8 Rivers Energy, located on the Southern Ute Indian Reservation. - FID expected in 2022, with power production targeted for 2025. - **Status in 2025**: No confirmation of FID or construction, likely in pre-FEED or FEED stage. - **Broadwing Clean Energy Complex (Decatur, Illinois, 280 MWe)**: - Developed by 8 Rivers with Archer-Daniels-Midland (ADM), targeting 2025. - **Status in 2025**: Likely in pre-FEED or FEED stage, with no confirmed construction. - **United Kingdom**: - **Whitetail Clean Energy Project (Teesside, 300 MWe, Natural Gas)**: - Planned by NET Power and Sembcorp Energy UK at the Wilton International site, aiming to capture 800,000 tons of CO2 annually. - Announced in July 2021, with commissioning targeted for 2025. - **Status in 2025**: No updates confirm progress. Likely in FEED phase or awaiting FID, with potential commissioning in 2026 or later. - **Other Potential Projects**: - NET Power and 8 Rivers are exploring sites in Europe, the Middle East, and Asia, with interest in co-locating with LNG terminals or industrial facilities. - No specific projects confirmed beyond those listed, with pre-FEED studies ongoing. - **Coal-Based Allam Cycle**: - 8 Rivers, with DOE support under the Coal FIRST initiative, completed a pre-FEED study for a coal-based cycle using gasified syngas, targeting mid-40s efficiency. - **Status in 2025**: No commercial coal-based plants are operational or under construction, with focus remaining on natural gas. **Barriers to Full Commercialization** 1. **Project Delays**: - Odessa and Teesside targeted 2025, but lack of updates suggests delays. FID, permitting, and financing challenges are common for first-of-a-kind technologies. - Earlier projections (e.g., 2020 for a 300 MWe plant) were optimistic, indicating slower progress. 2. **Economic Viability**: - Competitive with conventional natural gas plants without carbon capture, aided by U.S. 45Q tax credits (\$50/ton CO2 by 2026). - Without incentives or CO2 sales (e.g., for enhanced oil recovery), it is less economical than traditional natural gas combined cycle (NGCC) plants. 3. **CO2 Infrastructure**: - Relies on CO2 sequestration or utilization pipelines. The U.S. has \~5,000 miles of CO2 pipelines, but global expansion is limited, hindering international deployment. 4. **Scale-Up Challenges**: - Scaling from 50 MWth to 300 MWe involves risks in component reliability and integration. La Porte’s success mitigates some concerns, but commercial plants must prove long-term performance. 5. **Market Competition**: - Renewables (wind, solar) and battery storage are increasingly cost-competitive, reducing demand for new fossil fuel plants, even with carbon capture. **How Far from Commercialization?** - **Current Stage**: Late demonstration/early commercial phase. The La Porte plant has proven the technology, and the Odessa project is poised to be the first commercial-scale plant, potentially operational by 2026 if delays are minimal. - **Timeline**: Full commercialization (multiple operational plants) is likely 3–5 years away (2028–2030), assuming Odessa and Teesside succeed and attract investment. Additional projects (Coyote, Broadwing) could follow by the early 2030s. - **Distance**: Close to commercialization for natural gas, with one commercial plant nearing reality. Widespread adoption depends on policy support and market demand. **Conclusion** TAC is on the cusp of commercialization, with the 50 MWth La Porte plant operational and the 300 MWe Odessa plant in late development. Broader market adoption is 3–5 years away, pending successful project execution, policy support, and commercial use CO2 infrastructure expansion. Success of initial commercial plants may drive wider deployment by the early 2030s. *Compiled by John Schneller*