The Electric Power Research Institute (EPRI) says both projects involve adding steam generated by a solar thermal field to a conventional steam cycle, to create a ‘solar hybrid’ plant. One demonstration will be hosted by Tri-State Generation & Transmission Association at its 245 MW coal-fired Escalante generating station in Prewitt (New Mexico) while the other will be hosted by NV Energy at its 1102 MW gas-powered Lenzie facility near Las Vegas.
“Solar thermal hybrid applications have the potential to be an important, low-cost option for adding solar power to the generation fleet, allowing utilities to meet renewable energy regulatory targets, reduce plant emissions, and lower fuel costs,” explains EPRI.
The hybrid solar thermal system will inject solar-generated steam into the steam cycle of the fossil plants, and the approach solves the intermittency challenge of integrating solar power onto the grid without compromising the reliability of supply.
Data collected from the solar thermal hybrid projects will be provided to the industry and the general public by EPRI and the plant owners / operators through collaboratives created to support the host sites in selecting the integration design. They will conduct independent plant performance monitoring, evaluation and economic assessments of their planned projects.
“These projects will seek to demonstrate a near-term and cost-effective way to use solar energy at commercial scale,” says Carolyn Shockley of EPRI. “This is a key step along the road toward taking full advantage of technologies to lower the industry’s carbon footprint.”
The demonstrations will be conducted in conjunction with construction of new solar thermal facilities, and EPRI will provide support through all phases. It will rely on its expertise in solar technologies, including two studies on solar-augmented steam cycles that were completed last year. EPRI holds two patents in solar steam cycle optimisation.
The collaborative will help select solar thermal designs that can achieve the desired cost and performance targets, while maintaining the availability and reliability of the existing plant; develop plans for the hybrid plant performance evaluation and testing; and then carry out performance monitoring and evaluation, component testing, economic assessment, and reporting of operating parameters during plant commissioning.
EPRI is supporting 9 industry technology demonstrations as part of its efforts to develop a ‘full portfolio’ of technology approaches needed to make substantial CO2 emissions reductions while minimising economic impacts. Its analyses found that deployment of a full portfolio of advanced technologies (including carbon sequestration) could reduce US electric sector CO2 emissions by 2030 to pre-1990 levels. EPRI currently is working on a global analysis to show similar energy mix changes and significant economic impacts.
“Tri-State is investing in leading research in a number of innovative renewable energy technologies that bring value to our member cooperatives,” explains Ken Anderson of Tri-State. “We are intrigued with the positive results of EPRI’s solar augmentation study that was conducted at our Escalante generating station, and we are extremely interested in further exploring the practical application of this breakthrough technology that could further advance the efficiencies at one of our existing facilities.”
“We are excited about the possibility of integrating solar steam into one of our conventional natural gas fuelled power stations,” adds Tom Fair of NV Energy. “We anticipate this could be a great way to increase our use of solar energy, reduce overall emissions and maximise the use of our existing assets.”
Based in Denver, Tri-State is a wholesale electric power supplier owned by the 44 electric cooperatives that it serves. It generates and transmits electricity to its member systems over a 250,000 square-mile service territory in Colorado, Nebraska, New Mexico and Wyoming.
Headquartered in Las Vegas, NV Energy is a holding company with Nevada Power Company and Sierra Pacific Power Company as its major subsidiaries. Serving a combined service territory of 54,500 square miles, it provides energy services and products to 2.4 million citizens of Nevada and 40 million tourists a year.
EPRI conducts research and development on generation and consumption of electricity. Its members represent 90% of the power capacity in the United States, and international participation extends to 40 countries.