The U.S. Department of Energy’s National Energy Technology Laboratory (NETL), in partnership with Energy Industries of Ohio Inc., is set to scaleup the fabrication of components made from advanced nickel superalloys, that will help bring advanced ultrasupercritical (AUSC) power plant technology to the level of readiness for commercial-scale demonstration.

Conventional coal-fired power plants, which generate steam to drive a power generation turbine, operate with efficiencies varying from 32 to 42 percent, depending upon the age and design of the plant. AUSC power plants can potentially operate at temperatures and pressures higher than current state-of the-art coal-fired power plants —  about 25 percent more efficient than the average U.S. coal-fired power plant fleet, and 10 percent more efficient than state-of-the-art coal-fired power plants.

AUSC power plants would require less coal per megawatt-hour, resulting in lower emissions, and lower fuel costs per megawatt.

Successful wide-spread use of AUSC technology requires fabrication of advanced nickel superalloys into large plant components; development of installation and repair methods for the nickel superalloy components; and sufficient testing and metallurgical analysis to support the final design of a commercial-scale AUSC demonstration plant.

Since the early 2000s, NETL, working with a partnership consisting of the Energy Industries of Ohio, the Electric Power Research Institute and industry partners known as the AUSC Consortium, conducted AUSC research to the point that fabrication of AUSC nickel components is ready to be built at full commercial scale — the last stage of research and development before a commercial-scale demonstration of AUSC power plant technology can be implemented.

The DOE share of the $26.8 million project (DE-FE0025064) cost is $20 million with the project participants contributing $6.8 million. The project is anticipated to be finished at the end of September 2021.

The technical goal of the project is to bring AUSC technology to the commercial demonstration scale of technology readiness by manufacturing full scale AUSC components from nickel superalloys and other advanced alloys. The size of the components that will be fabricated correspond to a coal-fired power plant of approximately 800 megawatts generation capacity operating at a steam temperature of 760°C (1400°F) and steam pressure of at least 238 bar (3500 psia). The components that will be fabricated include an AUSC superheater tube assembly, large diameter thick wall pipe and pipe fittings, an AUSC steam turbine rotor and an AUSC steam turbine nozzle carrier casting.

The expected results of the project are:

• Development of a domestic supply chain for the fabrication of nickel superalloy and other AUSC power plant components.
• Validation of advanced design and life prediction methods for AUSC components that are made from nickel superalloys and other advanced creep resistant alloys in both steady state and cycling operating modes.
• Validation of the ability to design nickel superalloy and other AUSC components for operating life of least 30 years.
• Validation through design and fabrication that AUSC components can be designed and built for reliable operation under both steady state and varying load operating conditions.
• Development and validation of fabrication, installation and repair methods for cast and forged nickel superalloy AUSC power plant components and sub-assemblies.

Private sector partners involved in the current phase of the AUSC project include Energy Industries of Ohio, Electric Power Research Institute, ALSTOM Power Division of General Electric, Riley Power, MetalTek, Special Metals and AECOM.