UK's First Gas-Fired Allam Cycle Power Plant Taking Shape

The inventor of the Allam-Fetvedt Cycle, a novel power cycle that uses supercritical carbon dioxide (sCO2), is collaborating with a subsidiary of Singapore-based Sembcorp Industries to potentially develop the UK’s first 300-MW natural gas–fired NET Power station at an existing site at Teesside, northeastern England. 

Zero Degrees Whitetail Development Ltd. (ZDW), a subsidiary of North Carolina-based 8 Rivers Capital, and Sembcorp subsidiary Sembcorp Energy UK (SEUK) on July 13 said they will collaborate to set up the 300-MW Whitetail Clean Energy NET Power project at SEUK’s Wilton International site. While the companies did not provide a potential start date, 8 Rivers said the project may be the first of “multiple 300-MW facilities in the UK,” and that it could commission a NET Power station in the UK “as soon as 2025.”

The project is another notable prospect for 8 Rivers, which has been developing its potentially revolutionary power plant based on the Allam-Fetvedt Cycle (AFC) since 2012 under NET Power, a business arm it holds jointly with heavyweight industry backers Exelon, McDermott, and Occidental Low Carbon Ventures.

As POWER has reported, the AFC is essentially a specialized Brayton cycle that is directly fired with oxy-fuel and uses supercritical CO2 instead of steam as its working fluid. The cycle also recycles its exhaust heat and eliminates all air emissions, including traditional pollutants and CO2. As a byproduct, the cycle produces pipeline-quality CO2 that can be sequestered. NET Power has said these attributes could make it more cost-competitive and efficient than traditional gas power plants.

The NET Power Allam-Fetvedt Cycle is essentially a specialized Brayton cycle in which the combustor is supplied with three flows: fuel gas, which is compressed in the fuel compressor; oxygen, which is produced in an air separation unit and then compressed; and a carbon dioxide working fluid that is heated in the multi-flow regenerator. Combustion of this oxy-fuel mixture in the carbon dioxide environment creates high-temperature products that then enter the carbon dioxide turbine. These products drive the power generator and then enter the multi-flow regenerator, where some of their heat is transferred to the heated flows. The flow is then directed to the cooler-separator, where its water and carbon dioxide contents are split. Part of that carbon dioxide is compressed to supercritical pressure, and the rest is sent to storage. Courtesy: 8 Rivers

Along with testing the technology at a site in La Porte, Texas, just outside of Houston, 8 Rivers this April unveiled plans for two 280-MW NET Power natural gas–fired plants. These include the Coyote Clean Power Project in southwest Colorado, which will be located within the Southern Ute Indian Reservation, and the Broadwing Clean Energy Complex, which 8 Rivers is developing in partnership with agricultural and processing firm Archer-Daniels-Midlands Co. (ADM) at an existing carbon dioxide storage facility site in Decatur, Illinois. 

SEUK has been developing the 2,000-acre Wilton International site in Teesside’s industrial area as a multi-occupancy manufacturing hub with “plug and play” energy capabilities. The site is outfitted with water distribution and liquid effluent networks, and a natural gas distribution network, and it already has four combined heat and power (CHP) units—two fired with natural gas and two fired with biomass—with a combined capacity of up to 200 MW and a total steam output of 460 tonnes/hour.

Wilton International is also quickly growing into an innovation hub. In June, the site was chosen to host the onshore electricity converter station for RWE Renewables’ 1.4-GW Sofia Wind Farm, which is under development on Dogger Bank, 195 kilometers from the Teesside coast. 

“These services are complemented by our fleet of fast-acting, decentralized power stations and battery storage sites situated throughout England and Wales,” SEUK told POWER. “Monitored and controlled from our central operations facility in Solihull, these flexible assets deliver electricity to the national grid, helping to balance the UK energy system and ensure reliable power for homes and businesses.”

The Whitetail Clean Energy NET Power project, however, will look and operate differently, an 8 Rivers spokesman said. “This power station does not have massive chimneys unlike normal gas power stations. The process combusts natural gas with oxygen, rather than air, and uses supercritical carbon dioxide as a working fluid to drive a turbine instead of steam,” he explained.

Along with its production capacity of 300 MW of “clean” power, the Whitetail Clean Energy plant will also capture 800,000 tons of its carbon dioxide. The Wilton International site’s port and pipeline access will enable captured carbon dioxide to be “conveniently transported to UK sequestration sites [for permanent storage] in secure geological formations deep under the North Sea,” the company said.

Teesside Quickly Transforming Into Innovation, Decarbonization Hub

Teesside, notably, is also home to the Net Zero Teesside (NZT), a carbon capture, utilization, and storage (CCUS) project spearheaded by oil and gas firms BP, Eni, Equinor, Shell, and Total. When it starts up in 2026, the CCUS project will capture up to 10 million tonnes of carbon emissions each year. In March, NZT and two other industrial consortia—the Northern Endurance Partnership (NEP) and Zero Carbon Humber (ZCH)—garnered £229 million ($316 million) in private and public funding as part of the Industrial Decarbonization Challenge under the UK Research and Innovation’s Industrial Strategy Challenge Fund. As part of that project, NZT will develop “a new flexible gas-fired power station” with carbon capture and establish a carbon dioxide “gathering network” to enable decarbonization of industrial emitters, hydrogen production, and power generation in the Teesside area.

However, NZT, NEP, and ZCH on July 8 notably joined forces to form the “East Coast Cluster,” bidding jointly to the UK’s Department for Business, Energy, and Industrial Strategy (BEIS) “cluster sequencing” for CCUS deployment. The effort is rooted in the UK’s November 2020–issued 10-point plan for a Green Industrial Revolution. It envisions CCUS deployment in two industrial clusters by the mid-2020s, and a further two clusters by 2030 with an ambition to capture 10 MtCO2 per year by 2030. The East Coast Cluster, a collaboration between companies across Teesside and Humber—two regions that account for nearly 50% of all UK industrial cluster emissions—wants to secure offshore storage in the Endurance aquifer in the Southern North Sea.

UK Backing for NET Power 

The  Whitetail Clean Energy project also has the UK government’s support. 8 Rivers Capital said it completed a pre-FEED (front end engineering design) study for UK deployments of the AFC technology earlier this year with funding from the UK Department for Business, Energy & Industrial Strategy. “During its construction phase, Whitetail Clean Energy is expected to support over 2,000 direct, indirect, and induced jobs, including cascading supply chain opportunities. The clean energy facility is also expected to support the retraining of power generation engineers with enhanced skills to operate this innovative infrastructure project of national significance,” the firm said.

“Project Whitetail represents a key step towards Net Zero with the UK and US working in close collaboration. The Allam-Fetvedt Cycle technology was first supported by the UK Government’s Department for Energy and Climate Change in 2012, and the announcement today of the Whitetail Clean Energy project demonstrates the value of supporting research and development projects to support the UK’s efforts to achieve its Net Zero targets, with commercially scaled technologies today returning to the United Kingdom as proven concepts,” said Cam Hosie, 8 Rivers Capital CEO.

Ron DeGregorio, CEO of NET Power, meanwhile, lauded the UK for its vision. “Decarbonizing Teesside through NET Power’s groundbreaking technology is a critical step towards achieving the UK’s Net Zero emissions targets,” he said. “In addition to those two development partners, the UK Government has been instrumental in supporting this project, and its foresight and leadership on carbon capture and storage should serve as inspiration for the rest of the world to take bold action to achieve Net Zero.”

 Sonal Patel is a POWER senior associate editor (@sonalcpatel, @POWERmagazine)

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