With a goal of increasing power plant efficiency while incorporating renewable technologies, Tri-State Generation and Transmission Association has entered into an agreement with the Electric Power Research Institute to host a case study that is aimed at helping electric utilities add solar energy to fossil-fueled generating stations.
Tri-State’s 245-megawatt Escalante Station – a coal-based power plant located in Prewitt, N.M. – has been identified as the host facility for the study. The process to be studied involves introducing steam generated by a solar thermal field to the conventional power plant’s steam cycle to offset some of the fuel required to generate electricity.
Potential benefits of a solar-augmented steam-cycle facility include adding utility-scale solar power generation without the challenges of siting a new plant and new power block, reducing the facility’s carbon dioxide footprint and gaining valuable experience with solar thermal technologies to assess their future potential in a utility’s generation mix.
“Tri-State is investing in leading research in a number of innovative renewable energy technologies that bring value to our members,” said Ken Anderson, executive vice president and general manager at Tri-State. “We’re pleased to partner with EPRI on this project and we are eager to learn more about the potential of this breakthrough technology that could further advance the efficiencies at one of our existing generating facilities, while simultaneously help reduce our overall greenhouse gas emissions from the plant.
“The technology being studied would allow us a larger net output of electricity from Escalante Station, but without consuming more fuel to gain the additional electricity.”
The project – one of two similar efforts that EPRI is currently spearheading – will provide a conceptual design study, analyze options to retrofit the existing power plant and identify new plant design options. EPRI will rely on its expertise in solar technologies, steam cycles and plant operation, as well as past solar and fossil plant studies.
“These projects will demonstrate a near-term and cost-effective way to use large amounts of solar energy at commercial scale to provide clean electric power,” said Dr. Bryan Hannegan, vice president of generation and environment at EPRI.
“These ‘hybrid power plants’ will combine the low-cost reliability of existing fossil power plants with the environmental benefit of renewables, and help companies meet federal and state mandates to reduce their emissions of air pollutants and greenhouse gases with renewable energy.”
Dick Shirley, general manager of Continental Divide Electric Cooperative of Grants, N.M., one of 44 electric co-ops to which Tri-State provides wholesale power, said he is encouraged by Tri-State’s participation in the project.
“While I believe we’re going to continue to rely on coal-based power plants for a large portion of our electricity supply, we obviously have to look beyond fossil fuels to other, more sustainable forms of energy,” he said. “I support Tri-State’s efforts in pursuing new technologies and making their existing generation fleet more efficient.”
During the case study, the system’s performance will be analyzed by solar thermal research engineers at the U.S. Department of Energy’s Sandia National Laboratory in Albuquerque, N.M., and the National Renewable Energy Laboratory (NREL) in Golden, Colo. NREL works with industry to analyze the cost and performance of solar systems, design new technology for solar electricity generation and look for ways to improve the performance, reliability and service life of systems and their key components.
“One of the cost-effective aspects of concentrated solar power is that it can be fitted to an existing power plant to make electricity in tandem with fossil fuels,” said NREL’s Mark Mehos, CSP principal program manager. “And those existing plants already are connected to the transmission grid, making the technology relatively easy for utilities to work with. That can only help to expand the use of renewable energy.”
Tri-State also is participating with several other utilities on an EPRI-led solar-to-steam study project applied at natural gas-fueled, combined-cycle power plants in Arizona and Nevada.
“Even as we deal with a difficult economy, we are not shying away from critical investments in new programs and new technologies,” Anderson said. “As those emerge and scientific progress is made, Tri-State will seize new opportunities to further cultivate the local resources that enhance our power production and delivery system in order to bring more value to our member systems.”
Based in Denver, Tri-State supplies wholesale power throughout a 250,000-square-mile service territory to 18 electric cooperatives in Colorado, 12 in New Mexico, eight in Wyoming and six in western Nebraska. The 44 co-ops, in turn, provide electricity to more than 600,000 meters, which translates to a population of approximately 1.4 million end-use consumers.
The Electric Power Research Institute conducts research and development relating to the generation, delivery and use of electricity for the benefit of the public. An independent, non-profit organization, EPRI brings together its scientists and engineers as well as experts from academia and industry to help address challenges in electricity, including reliability, efficiency, health, safety and the environment. EPRI’s members represent more than 90 percent of the electricity generated and delivered in the United States, and international participation extends to 40 countries. EPRI’s principal offices and laboratories are located in Palo Alto, Calif.; Charlotte, N.C.; Knoxville, Tenn.; and Lenox, Mass.
