To accomplish the goals of the SunShot Initiative, the concentrating solar power (CSP) subprogram partners with government agencies and the solar industry to encourage the development and deployment of CSP technologies.
The subprogram's CSP efforts focus on lowering costs and advancing technologies to make concentrating solar power cost-competitive in the market. Program highlights are grouped into the following categories:
The Department of Energy (DOE) works closely with its industry partners and national laboratories to support the CSP industry with critical research and development projects that address cost, reliability, performance, and manufacturing challenges.
Enabling Power Generation with Storage Capability
Low-cost, high-performance concentrating solar power (CSP) technologies are needed to achieve the goals set by the U.S. Department of Energy (DOE) as part of its SunShot Initiative. DOE supports CSP research and development efforts on linear concentrator, dish/engine, and power tower systems with thermal energy storage capabilities that allow for power generation in the absence of sunlight. Featured projects associated with the CSP subprogram are highlighted below.
CSP Plant with Thermal Storage Moves Forward
Abengoa Solar received a $1.45 billion loan guarantee from DOE to move forward with the Solana solar project near Gila Bend, Arizona. The 250-megawatt (MW) parabolic trough concentrating solar plant covers 3 square miles with approximately 2,700 trough collectors. The project represents the first large-scale U.S. solar plant capable of storing the energy generated from steam turbines. The Solana CSP plant will:
Produce enough energy to serve 70,000 households
Ivanpah to be World's Largest Solar Electric Generating System
The Ivanpah Solar Electric Generating System (SEGS), located on federal land in the Mojave Desert near the California-Nevada border, is poised to become the first U.S. commercial application of a high-tech steam tower system. Ivanpah will also become the largest solar thermal plant in the world, with a capacity of 370 MW. DOE supported this pioneering innovation in 2010 with conditional commitments of more than $1.37 billion in loan guarantees to the project operator, BrightSource Energy. Because CSP captures an even greater percentage of solar energy than other solar technologies, it is in harmony with the SunShot Initiative's goal of making solar energy technologies cost-competitive with other forms of unsubsidized energy. According to a power purchase agreement approved by the California Public Utilities Commission, the electricity will flow to a California utility by September 30, 2013.
National Laboratory Research Receives Boost
Through the utilization of funds from the American Recovery and Reinvestment Act of 2009 (Recovery Act), the CSP subprogram received $22.7 million to upgrade research and development facilities at Sandia National Laboratories and the National Renewable Energy Laboratory (NREL). Sandia will use the funding to focus on thermal storage and advanced systems testing. NREL will develop a materials research laboratory and advanced thermal storage facility. In addition, the CSP subprogram issued a $4.7 million National Laboratory Call through Recovery Act funds under which advanced thermal energy storage and heat transfer fluids research will be conducted. Funding was awarded to NREL, Argonne National Laboratory, Oak Ridge National Laboratory, Los Alamos National Laboratory, Pacific Northwest National Laboratory, and Savannah River National Laboratory. These contracts complement and support DOE's ongoing private sector work.
Increasing Access for Concentrating Solar Power
The U.S. Department of Energy (DOE) has identified land access and transmission capabilities as two of the primary barriers associated with large-scale deployment of concentrating solar power (CSP). Strategic government and industry partnerships are needed to build operational CSP plants that demonstrate viability and lower costs. The highlighted projects below show the progress being made in this area.
DOE Partners with BLM, DOI to Develop Solar Energy Study Areas
DOE's CSP subprogram is co-leading a programmatic environmental impact statement with the U.S. Department of the Interior's (DOI) Bureau of Land Management (BLM). The purpose of the environmental impact statement is to identify suitable federal land for utility-scale solar project development. Others participating in this effort include the California Energy Commission, the California Public Utilities Commission, the U.S. Department of Defense, and Argonne National Laboratory. Thus far, 24 solar energy study areas have been identified, totaling 676,000 acres of land.
In addition, DOE and DOI established the Solar Demonstration Project to test cutting-edge CSP technologies. The 25 square-mile demonstration site in Nevada will serve as a proving ground for new technologies, while also providing a critical link between DOE and the solar industry's advanced technology development activities and full-scale commercialization efforts.
Concentrating Solar Power Industry Projects
The U.S. Department of Energy (DOE) partners with various concentrating solar power (CSP) companies by supporting their research efforts. The DOE Solar Energy Technologies Program is funding nearly 30 industry projects.
Each company was selected through a competitive selection process, and the goal of these projects is to lower technology and manufacturing costs, increase conversion efficiencies, and improve the reliability of components and systems.
Although the CSP financial opportunities related to the projects listed here are closed, other open and upcoming opportunities are posted on the financial opportunities section.
Each of the CSP projects are listed below by specific research and development (R&D) areas, along with its primary goals.
Dish/Engine Systems Thermal Storage
The goals for these linear concentrator research and development (R&D) projects include improving the performance and lowering the cost of parabolic trough collector systems and supporting the development of next-generation trough fields.
SkyFuel Inc., Linear Fresnel Power Tower CSP Plant
Developing an advanced CSP system, using linear Fresnel reflective technology, to achieve significantly lower delivered electricity costs from utility-scale solar thermal power plants.
Alcoa, Inc., Reflector Technology Development and System Design for CSP Technologies
Pursuing lower trough system costs by optimizing the design of the collector assembly, including reduced reflector weight, improved supporting structure joint design, and increased reflector stiffness.
Abengoa Solar, Parabolic Trough Collectors
Developing innovative and improved parabolic trough collector designs that can significantly lower cost.
Solar Millennium LLC, Advanced High-Temperature Trough Collector Development
Designing and manufacturing a higher-performance, lower-cost trough collector system with the potential to operate with molten-salt heat-transfer fluid and storage.
3M Company, Cleanable and Hardcoat Coatings for Increased Durability of Silvered Polymeric Mirrors
Improving the abrasion resistance and cleanability of the front surface of a silvered polymeric mirror to decrease the rate of reflectance loss and irreversible soiling by 50% relative to an untreated surface.
Abengoa Solar, Advanced Polymeric Reflectors
Developing an advanced solar reflective material that will be transitioned from the laboratory scale to limited production runs at a commercial scale.
PPG Industries, High-Value Mirrors
Developing mirrors that include an inorganic coating to protect the mirror from chemical attack, an organic coating to protect the mirror from mechanical attack, and a low-cost fabrication process.
The goals for these dish/engine R&D projects include improving the performance and lowering the cost of dish/Stirling systems and providing optical modeling and testing support to the dish/Stirling industry.
Brayton Energy, Brayton SolarCAT Solar Power Conversion System
Lowering the capital costs and increasing system reliability through improved engine and receiver efficiency, and also improving the mechanical integration of the engine, combustor, and receiver.
Infinia Corporation, 30-kW Maintenance-Free Stirling Engine
Combining six modified free-piston engines to form a 30-kilowatt, six-cylinder Stirling engine for high-performance, high-reliability dish concentrating solar power.
The goals for these thermal storage R&D projects include developing advanced heat-transfer fluids and thermal storage systems, developing thermal-storage materials and systems to reduce storage costs, and integrating thermal storage cost and performance models into CSP system models.
Abengoa Solar, Molten-Salt Heat-Transfer Fluid
Combining the use of a molten-salt heat-transfer fluid with molten-salt thermal energy storage to reduce the costs and increase the dispatchability of CSP plants.
Hamilton Sunstrand SLS Rocketdyne Corporation, Molten-Salt Pump
Designing, building, and testing a molten-salt pump with a long shaft (about 50 feet) that can operate at 1,050°F (566°C); this component is critical for both trough and tower technologies.
Symyx, Eutectic Salt Formulations as Advanced Heat-Transfer Fluids
Finding eutectic salts that can operate within a temperature range of 80° to 500°C with a significantly increased heat capacity.
Abengoa, Advanced Thermal Energy Storage for Central Receivers and Supercritical Coolants
Testing heat-transport fluids in a power-tower plant, in combination with ceramic themocline storage, to determine reductions in levelized energy cost.
Acciona, Sensible Heat, Direct, Dual-Media Module
Designing a heat-storage module in which the heat-transfer fluid flows through a solid storage media.
City University of New York, Storage Method for CSP Plants to Operate at High Temperatures
Testing carbon dioxide as the heat-transfer fluid and solid ceramics for storage, operating at higher temperatures that will lower the cost of the system.
General Atomics, Thermochemical Heat Storage
Using thermochemical cycles to store solar heat and conducting experimental feasibility studies on select systems.
Infinia Corporation, Maintenance-Free Phase-Change Thermal Energy Storage
Integrating a thermal energy storage module with a dish/Stirling engine, enabling the system to operate during cloud transients and to provide dispatchable power for 4 to 6 hours after sunset.
Lehigh University, Novel Storage Technologies
Exploring the containment of phase-change materials to operate at temperatures near 400°C.
Terrafore, Heat Transfer and Latent Heat Storage in Inorganic Molten Salts
Exploring the flow and heat-transfer properties of dilute eutectic mixtures of inorganic salts, as well as designing a compatible heat exchanger.
Texas Engineering Experiment Station, Molten-Salt Carbon-Nanotube Thermal Energy Storage
Suspending carbon nanotubes in a molten-salt material to improve thermal stability, heat capacity, and thermal conductivity in the thermal region of 500° to 600°C.
University of Alabama, Novel Molten Salts Thermal Energy Storage
Developing low-melting-point molten-salt storage media with high thermal energy density for sensible heat storage.
University of Arkansas, Development and Performance Evaluation of High-Temperature Concrete
Examining the characteristics of ultra-high-performance concrete, particularly its performance in temperatures up to 600°C.
University of Connecticut, Novel Thermal Energy Storage
Embedding thermosyphons, a method of passive heat exchange based on natural convection, and/or heat pipes with phase-change materials to determine if they can significantly reduce thermal resistance within those materials.
Abengoa, Cost Reductions of Thermal Energy Storage for Parabolic Troughs
Analyzing opportunities to reduce costs by 20%–25%, using an indirect two-tank molten-salt design as the baseline of comparison.
Acciona, Indirect, Dual-Media, Phase-Change-Material Thermal Energy Storage Module
Demonstrating an 800-megawatt, 4-hour thermal energy storage system, using phase-change material, that can be integrated into Acciona's 64-megawatt trough plant in Boulder City, Nevada.
U.S. Solar Holdings, Comparison of Technologies for CSP Energy Storage Solutions
Exploring storage technologies, including a thermocline single-tank storage system and sand shifter (a two-silo thermal-mass storage system), that will be integrated with the Arizona Public Service 1-megawatt CSP plant in Red Rock, Arizona.
Advanced Components and Systems
The advanced components and systems R&D goals include lowering costs and improving performance and reliability of solar mirrors and unifying test methods to standardize qualification requirements of CSP materials, components, and systems.
Hamilton Sunstrand SLS Rocketdyne Corporation, Central-Receiver Panel Fabrication and Testing
Manufacturing and testing of a large-scale (200-megawatt) molten-salt solar receiver panel for power-tower technology.