Features - June 2016

NETL and the Advanced Ultrasupercritical (AUSC) Boiler Consortium

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The global population is rising—correspondingly, the demand for energy worldwide continues to increase with no signs of abating. To meet this growing need for power, energy science must advance. While it is necessary to diversify the energy portfolio available to us, traditional methods of power generation must also be used. To ensure a secure energy future for America, power plants that rely on fossil fuels must be upgraded to become both cleaner and more efficient.

In response to this need, the U.S. Department of Energy (DOE), through the National Energy Technology Laboratory (NETL), has undertaken a project to create the materials needed to construct the next generation of advanced ultrasupercritical (AUSC) power plants. The project, called the AUSC Boiler Consortium, was a collaborative partnership between DOE and multiple industry participants with the Electric Power Research Institute taking the lead.

AUSC power plants are high-efficiency, coal-fired power generation facilities. Compared to earlier systems, these plants increase the amount of electricity able to be produced from coal. As a result, the amount of CO2 that must be captured from an AUSC power plant is lower than the amount of CO2 that must be captured from a traditional power plant when producing the same amount of electricity.

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To achieve such efficiencies, AUSC power plants must run at temperatures and pressures that are greater than any power plants have ever attempted to operate. This means that new materials must be constructed that can withstand the extreme environments of these power plants. In recognition of this need, industry and government began a collaborative partnership to develop such materials: the AUSC Boiler Consortium. Tasked with identifying, evaluating, and qualifying high-temperature materials for boiler operations, the project has spanned many years but has ultimately yielded results.

The project was a complicated endeavor with many many facets, including conceptual design and economic analysis, mechanical properties, steamside oxidation and resistance, fireside corrosion, weldability, fabricability, coatings, and alterations to existing design codes. Each of these tasks was tackled separately, but all contributed to the success of the project. After 15 years of research and development efforts, the Consortium identified and developed two nickel-based super alloys that are critical to the success of AUSC power plants: Inconel 740H and Haynes H282. The former has been approved by the American Society of Mechanical Engineers and the latter is undergoing lab tests to develop a Code Case for the society.

While the AUSC Consortium concluded its efforts at the end of 2015, the next step has already been put into motion. In November 2015, NETL approved a project designed to bring the alloys closer to commercial demonstration readiness. The new phase is ComTest, or Component Test, and many of the partners involved in the Consortium intend to participate in this next step. The collaboration that proved so successful in the last project will be extended into the new partnership, bringing along the skill sets, expertise, and cordial working relationships that made the Consortium so fruitful. ComTest expects that the materials being tested may become commercially available as early as 2030.

There are no easy answers to the energy challenges that face our Nation and the world, but every step taken by dedicated energy scientists brings us closer to realizing a robust and secure energy future.