Ultrahigh Temperature Impervious Materials Advancing Turbine Efficiency
The ULTIMATE program targets gas turbine applications in the power generation and aviation industries. ULTIMATE aims to develop ultrahigh temperature materials for gas turbines, enabling them to operate continuously at 1300 ºC (2372 ºF) in a stand-alone material test environment—or with coatings, enabling gas turbine inlet temperatures of 1800 ºC (3272 ºF) or higher. The successful materials must be able to withstand not only the highest temperature in a turbine but also the extreme stresses imposed on turbine blades. This program will concurrently develop manufacturing processes for turbine components using these materials, enabling complex geometries that can be seamlessly integrated in the system design. Environmental barrier coatings and thermal barrier coatings are within the scope of this program.
ULTIMATE consists of two separate phases, which may be proposed for a maximum of 18 and 24 months, respectively. In phase I, project teams will demonstrate proof of concept of their alloy compositions, coatings, and manufacturing processes through modeling and laboratory scale tensile coupon (sample) testing of basic properties. In phase II, approved project teams will investigate selected alloy compositions and coatings to evaluate a comprehensive suite of physical, chemical, and mechanical properties as well as produce generic small-scale turbine blades to demonstrate manufacturability.
Today, natural gas turbines produce approximately 35% of the total electricity production in the U.S. Improving their efficiency is important for reducing energy usage and carbon emissions, as well as improving the economics of aviation power generation and other industrial sectors. Gas turbine efficiency largely depends on the temperature of the gas at the inlet; the higher the temperature, the higher the efficiency. The operational temperature of gas turbines is currently limited by its component materials, particularly those in the path of the hot gas such as turbine blades, vanes, nozzles, and shrouds. Turbine blades experience the greatest operational burden because they must concurrently withstand the highest temperatures and stresses. Currently, turbine blades are made of single crystal nickel (Ni)- or cobalt (Co)-based superalloys. After many years of refinements, their development has plateaued. There is a strong need to discover, develop, and implement novel materials that work at temperatures significantly higher than that of the Ni or Co superalloys if further efficiency gains are to be realized. ARPA-E believes this is the right time to leverage and integrate recent advances in alloy design and modeling, refractory alloys, advanced manufacturing technologies, and high-throughput testing to realize significant improvements in the operational capability of gas turbines.
The development of new ultrahigh temperature materials with compatible coatings and manufacturing technologies has the potential to increase gas turbine efficiency up to 7%, which will significantly reduce wasted energy and carbon emissions.
Electricity generation, coal, and nuclear markets are currently saturated with gas generation units well past their useful life. Increasing gas turbine efficiency is critical to ensuring that the plants can effectively deploy their capacity to the grid, increasing energy security.
Improving gas turbine efficiency can significantly reduce carbon emissions from air travel, which represents 2% of all global carbon emissions.
By 2050, a 7% efficiency improvement in the natural gas turbines used for U.S. electricity generation could save up to 15-16 quads of energy; in civilian aircraft turbines, 3-4 quads could be saved for U.S. air travel.