DOE Project Highlights Advantages of Hybrid Energy Storage
ENERGY SECURITY, ECONOMIC SAVINGS, LOWER EMISSIONS
(Palo Alto, California—March 28, 2022) Confronted with accelerated timelines to dramatically reduce carbon by 2030 while maintaining reliability during seasonal and extreme weather events, a new study for the U.S. Department of Energy’s National Energy Technology Laboratory (NETL) offers electricity providers a rapid and feasible path: hybridize long-duration thermal energy storage with the thermal power generation that provides most of the nation’s peaking power and overnight electricity.
In collaboration with the Electric Power Research Institute (EPRI), Pintail Power LLC’s Liquid Salt Combined Cycle™ (LSCC) hybrid process was studied for NETL. The novel large-scale, long-duration hybrid process uses liquid salt as a safe, low-cost medium for storing renewable energy, while cutting fuel use in half and improving the ability of thermal power plants to respond to renewable variability.
As the prime recipient, EPRI managed the project, which included assessment of technology readiness, conceptual design, techno-economic analysis, and commercialization plan.
The project evaluated the performance, cost, operation, economics, and commercial potential for LSCC technology retrofitted to an existing power plant. Cost estimates developed by an independent engineer using vendor quotes for a 92 MW plant with 19 hours of storage showed the total installed cost per kWh to be less than one-third that of battery energy storage, making LSCC the cost leader for large-scale, long-duration energy storage applications. The commercial assessment found that the technology would be economically competitive, without subsidies, in the ERCOT energy market. Utilities interviewed by EPRI unanimously expressed interest in the approach.
How it works
The LSCC technology uses proven two-tank molten salt thermal energy storage, charged by electric heaters from grid-connected resources, such as wind or solar power. When needed, the stored thermal energy is discharged by evaporating water in a boiler, while gas turbine exhaust
heats the boiler feedwater and then superheats the steam. Integrating stored energy in this manner increases the overall efficiency – reducing the amount of fuel needed per kWh of electricity and producing more kWh of electricity per unit of stored energy.
The technology can be added to existing gas turbine power plants of any size, to enable them to store renewable energy and provide flexible ramping, regulation, and other essential grid reliability services, only consuming fuel when discharging electricity. The stored energy is used to enable the thermal power plant to start quickly, like a gas peaker, but with twice the fuel efficiency.
Dr. William M. Conlon, President of Pintail Power said, “Our objective is reduce cost and risk by using proven utility-scale equipment to accelerate the clean energy transition.” While fossil fuels remain needed during the transition to zero carbon, the hybrid approach delivers a triple bottom line – energy security, economic savings, and lower emissions. Conlon added, “By using stored renewable energy to reduce fuel consumption, we can improve grid reliability, make it more practical to fully decarbonize with hydrogen and reduce the cost and climate impact of burning fossil fuels today.”
EPRI Project Manager Scott Hume stated, “As we approach 100% renewable power, LSCC could provide synchronous inertia to stabilize grids, without burning fuel, and then ramp quickly as wind or solar power fade.”
The study was funded by the U.S. Department of Energy under contract DE-FE-0032016.
About Pintail Power
Pintail Power provides hybrid process technologies to utilities, independent power producers and developers to accelerate the transition to low-carbon electricity. In addition to LSCC technology, Pintail Power also provides Liquid Air Combined Cycle (LACC) technology for large-scale multi-day storage. http://www.pintailpower.com