Concentrating Solar Power Research and Development
Concentrating Solar Power (CSP) technologies use mirrors to reflect and concentrate sunlight to produce heat, which is then used to produce electricity. CSP systems are distinguished from other solar energy technologies by their ability to store energy as heat so that consumer demand can be met even when the sun is not shining, including during the night. These systems can be combined with existing fossil-fuel plants to allow for flexible power generation. Watch the Energy 101 video to learn more about CSP technologies.
These projects will help speed innovations in new components to lower costs, increase operating temperatures and improve the efficiency of CSP systems. The 3-year applied research projects announced today will focus on achieving dramatic improvements in CSP performance, while driving progress toward the SunShot goal of 75 percent cost reduction, so that this promising technology can deliver more clean, renewable energy to millions of homes and businesses across the country.
The research projects, conducted in partnership with private industry, national laboratories and universities, support the Energy Department’s SunShot Initiative, a collaborative national effort to make solar power cost-competitive with traditional energy sources by the end of the decade.
- Increasing system efficiency through higher-temperature operations
- Minimizing optical and thermal efficiency losses in the system
- Reducing the cost of the solar field.
|Project Title||Awardee||Description||DOE Amount||Recipient Amount||Primary Project Location|
|Next-Generation Solar Collectors|
Solar collectors represent the most expensive component of a CSP system. 3M Company is developing high-reflectivity films and high-rigidity structures that can replace current solar collectors that use heavy glass mirrors. The research team is creating a new set of technologies, including novel reflective films, reflector panels, space-frame structural elements, and adaptive opticsRead more...
|St. Paul, Minnesota|
|Chemically Reactive Working Fluids|
Argonne National Laboratory
Argonne National Laboratory (ANL) is working to identify and test new heat-transfer fluids (HTFs) that store energy chemically for more efficient energy transfer in CSP applications. The research team is working to demonstrate the feasibility of using chemically reacting working fluids (CRWFs) as an HTF.Read more...
|Self-Cleaning CSP Collectors|
This project aims to develop a new method to keep solar collectors dirt- and dust-free and thereby maintain high optical efficiency. This project will develop large-scale prototypes, cost-effective manufacturing processes, and commercialization of the technology in large-scale CSP devices for their applications in semi-arid and desert climates.Read more...
|High-Efficiency Receivers for Supercritical Carbon Dioxide Cycles|
Brayton Energy is building and testing a new solar receiver that uses supercritical carbon dioxide (s-CO2) as the heat-transfer fluid. The research team is designing the receiver to withstand higher operating temperatures and pressures than current state-of-the-art technology so that the device can enable higher efficiency systems.Read more...
|Hampton, New Hampshire|
|Flexible Assembly Solar Technology|
BrightSource Energy is designing and deploying an automated collector-assembly platform. The researchers are also developing a more efficient installation process that has the potential to drastically reduce construction time and cost for utility-scale CSP facilities.
BrightSource's research objective is to design, build, and demonstrate a Flexible Assembly Solar Technology (FAST) system that can substantially reduce the cost and time associated with solar-field construction. FAST accelerates the heliostat assembly and field installation processes by combining elements of both functions on a single platform with direct access to the solar collector field.Read more...
|Low-Cost, Lightweight Solar Concentrators|
Jet Propulsion Laboratory
The Jet Propulsion Laboratory (JPL) is designing an optimized solar thermal collector structure using a lightweight collector structure capable of lowering structural costs, simplifying installation, and leading to mass-manufacturability.
The JPL project seeks to achieve the SunShot Initiative installed cost target of $75/square meter for a solar thermal collector system, as well as SunShot performance targets for optical errors, operations during windy conditions, and lifetime.Read more...
|Concentrated Solar Thermoelectric Power|
Massachusetts Institute of Technology (MIT)
The Rohsenow-Kendall Heat Transfer Lab at Massachusetts Institute of Technology (MIT) is developing concentrated solar thermoelectric generators (CSTEGs) for CSP systems. This innovative distributed solution contains no moving parts and converts heat directly into electricity. Thermal storage can be integrated into the system, creating a reliable and flexible source of electricity.
MIT's innovative approach is a significant departure from current CSP systems. The solar thermoelectric generators are based on solid-state thermoelectric devices, and yet, they can store solar energy in the form of heat. When combined with thermal storage, such CSTEGs can provide electricity day and night while eliminating the mechanical power generation blocks. Furthermore, CSTEGs can also be used at small scale, such as commercial rooftops, to provide 24-hour distributed solar power. If successful, CSTEGs introduce a new and viable CSP technology capable of achieving the SunShot Initiative's goal of $0.06 per kilowatt-hour.Read more...
|10-Megawatt Supercritical Carbon Dioxide Turbine|
National Renewable Energy Laboratory
The National Renewable Energy Laboratory (NREL) and its partners aim to demonstrate a multi-megawatt power cycle using supercritical carbon dioxide (s-CO2) as the working fluid. The use of carbon dioxide instead of steam allows higher power-cycle efficiency and cycle components that are more compact.
The research team intends to showcase the turbomachinery for a new cycle—the s-CO2 Brayton cycle. During the past decade, researchers have modeled the basic thermodynamics of the cycle and tested it to explore the behavior of s-CO2 turbomachinery and operational/control characteristics of a closed Brayton cycle. However, to establish the true potential of this power cycle, the industry needs validation via the operation of a larger-scale prototype at temperatures relevant to CSP systems.
The proposed s-CO2 system uses no water, which is significant given that CSP plants are typically located in hot, dry climates where water is scarce. Researchers plan to demonstrate the inherent efficiencies of the s-CO2 power turbine and associated turbomachinery at a scale relevant to commercial CSP projects. Success in this endeavor will provide a foundation for solar applications that exceed the SunShot Initiative's goal of 50% net thermal-to-electric conversion efficiency.Read more...
|Particle Receiver Integrated with a Fluidized Bed|
National Renewable Energy Laboratory
The National Renewable Energy Laboratory (NREL) and its partners are developing a novel receiver that uses falling particles instead of liquid for the heat-transfer fluid (HTF). The research team aims to build a receiver that operates at higher temperatures and efficiencies than the current state-of-the-art technology.
The research team is designing a receiver with near-blackbody (NBB) absorptive performance. The concept uses low-cost stable materials, a ceramic solar receiver, and storage containers with refractory liners, which can accommodate temperatures much higher than can oil or salt and ordinary metals or metal alloys, and at a fraction of the cost.Read more...
|Advanced Low-Cost Receivers for Parabolic Troughs|
Norwich Technologies is developing a novel receiver for parabolic trough CSP systems that will dramatically improve performance while substantially reducing acquisition and operation and maintenance (O&M) costs. Norwich Technologies' diverse advances in materials and coatings are capable of revolutionizing all aspects of CSP trough receiver design. This receiver offers the prospect for reduced costs, combined with dramatic efficiency improvements. In addition, the technology enables significant operational and cost advances in parabolic trough CSP, which could potentially enable rapid, widespread adoption in new and retrofitted installations.Read more...
|High-Flux Microchannel Solar Receiver|
Oregon State University
Oregon State University and its partners are working to develop an advanced heat exchanger for use in CSP receivers. The heat exchanger has the potential to significantly increase heat transfer and reduce the size of the receiver.
The research team seeks to reduce the size, weight, and thermal loss from high-temperature solar receivers by applying microchannel heat-transfer technology to solar-receiver design. The extremely high heat-transfer rates afforded by microchannels are expected to enable the development of a receiver that can absorb high solar flux, while using a variety of liquid and gaseous working fluids.
The novel use of microchannels for enhanced heat transfer in solar receivers has the potential to significantly reduce device size and increase performance. The research team also intends to develop novel adaptive flow-control devices capable of redistributing flow as solar flux varies with time.Read more...
|Integrated Solar Thermochemical Reaction|
Pacific Northwest National Laboratory
Pacific Northwest National Laboratory is creating a new CSP method for hybridization with fossil-fuel plants. The system uses solar energy to drive a chemical reaction that produces a gas capable of offsetting the need for fossil fuels in traditional power plants.
The research team is working to significantly advance the technology readiness level of a CSP system based on parabolic dish concentrators and thermochemical reaction systems that provide a solar thermochemical augment of at least 20% to a chemical fuel (i.e., methane from natural gas or biogas) for use in a modified natural-gas combined-cycle (NGCC) power plant.
This highly efficient solar thermochemical reaction system is innovative in a variety of ways. First, it uses a modified NGCC that is already well-developed at high efficiency and can be constructed with relatively low capital costs compared to other power-generation options. Second, the system is capable of operating around the clock, regardless of the availability of sunlight and without requiring energy storage. Finally, the development and commercialization path to this system is relatively short, so it can be commercialized and operational at multiple locations before 2020.
|Scattering Solar Thermal Concentrators|
Pennsylvania State University
Pennsylvania State University is designing and testing a novel solar collector system that relies on stationary optics, avoiding the need for mirror movement. The system is capable of achieving optical performance equal to state-of-the-art parabolic trough systems, but at a lower cost.
The research team is working to demonstrate a scattering solar concentrator with optical performance equal to existing designs of state-of-the-art parabolic troughs, but with the added benefits of immunity to wind-load tracking error, more-efficient land use, and elimination of movable heat-transfer elements.
The Penn State scattering concentrator represents an entirely new way of concentrating sunlight. It incorporates fixed-focus collection optics and scattering into the waveguide modes of a guide sheet. This innovative design represents a hybrid between the high efficiency of conventional geometric optical concentration and the stationary simplicity of luminescent light-trapping. The design’s success constitutes a leap forward in performance and reliability for the collector field—thanks to immunity from wind loading and eliminating the need for movable heat-transfer elements and spectrally selective coatings.
|University Park, Pennsylvania|
|A Small-Particle Receiver for Brayton Cycles|
San Diego State University
San Diego State University (SDSU) is demonstrating a new receiver design that uses air as the heat-transfer fluid. The University's innovative small-particle heat-exchange receiver (SPHER) uses carbon particles to enhance performance and achieve higher thermal efficiency.
The SDSU research team is working to design, construct, and test a revolutionary, high-temperature solar receiver in the multi-megawatt range that can drive a gas turbine to generate low-cost electricity.
The concept of a volumetric, selective, and continually replenishable absorber is entirely unique. SPHER uses a dilute suspension of carbon nanoparticles dispersed in air to absorb highly-concentrated solar flux volumetrically inside a windowed pressure vessel, rather than on a solid surface as in most other receivers. The small-sized particles rapidly transfer heat to the surrounding air and then oxidize as temperatures increase. A hot, pressurized, clear gas stream consisting almost entirely of air with a small amount of carbon dioxide is then available to drive a gas turbine or be used for a process. This system can readily be hybridized with natural gas plants.
|San Diego, California|
|High-Temperature Falling-Particle Receiver|
Sandia National Laboratories
Sandia National Laboratories with partners Georgia Tech, Bucknell University, King Saud University, and DLR, are developing a falling-particle receiver and heat-exchanger system to increase efficiency and lower costs.
This project seeks to advance falling-particle receivers by passing particles through a receiver with recirculation that allows more heat to be transferred to the particles. The concept enables higher temperatures and greater efficiencies at a lower cost as compared to today's receivers.
The use of solid particles as the heat-transfer and storage media—rather than conventional fluids such as liquid molten salts or air—is unique. The falling-particle receiver appears well suited for power tower systems ranging from 10–100 megawatts. Such flexibility, combined with lower costs of thermal energy storage, could enable higher penetrations of CSP systems and help meet SunShot Initiative goals.Read more...
|Albuquerque, New Mexico|
|CSP Tower Air Brayton Combustor|
Southwest Research Institute
The Southwest Research Institute (SWRI) and its partners are developing an external combustor capable of operating at much higher temperatures than the current state-of-the-art technology.
This project addresses key technical hurdles for an optimized CSP central tower hybrid gas turbine system to increase energy conversion efficiency to greater than 50%, greatly reduce or eliminate carbon dioxide emissions, and generate dispatchable power at full load regardless of the time of day or meteorological conditions.
This external combustor may be the first designed for a full megawatt-scale gas turbine that is integrated and optimized for CSP. The radically different design uses novel materials being developed specifically for this application. This technology, if successful, would also stretch industrial gas-turbine combustion systems beyond the operating limits of current combustion inlet materials.Read more...
|San Antonio, Texas|
|Supercritical Carbon Dioxide Turbo-Expander and Heat Exchangers|
Southwest Research Institute
The Southwest Research Institute (SWRI) and its partners will develop an external combustor that is capable of operating at much higher temperatures and allows for the mixing of CSP-heated air with natural gas in hybridized power plants.
The project aims to develop a supercritical carbon dioxide (s-CO2) power cycle that combines high efficiencies and low costs for modular CSP applications. The SWRI team is working to advance the state-of-the-art s-CO2 turbo-expander design from laboratory testing to full prototype demonstration.
The scalable s-CO2 expander design and improved heat exchanger close two critical technology gaps required for an optimized CSP s-CO2 power plant. Successfully developing these systems represents a major stepping stone on the pathway to achieving a levelized cost of energy of $0.06 per kilowatt-hour, and increasing energy conversion efficiency to greater than 50%.
|San Antonio, Texas|
|Next-Generation Thermionic Solar Energy Conversion|
Stanford University/SLAC National Accelerator Laboratory
Stanford University and the SLAC National Accelerator Laboratory is designing and testing an innovative high-temperature power cycle for CSP systems that does not require any mechanical equipment, resulting in reduced maintenance costs. In addition, the system can be integrated with conventional CSP cycles to create ultra-efficient plants.
The SLAC/Stanford University research team is creating a new solid-state energy conversion technology based on microfabricated and photon-enhanced thermionic energy converters (PTECs). When used as a topping cycle in concentrated solar thermal electricity generation, PTECs will enable system efficiencies in excess of 50%.
Through the use of modern design tools and wafer-scale microfabrication methods, this project is demonstrating for the first time a manufacturable approach to thermionic energy converter production that overcomes the space-charge-induced efficiency limitations of traditional thermionic devices. Also, through the novel application of appropriately designed and fabricated semiconductor heterostructure cathodes, the efficiency is being further improved by the photon-enhanced thermionic emission process.
|Heliostat System with Wireless Closed-Loop Control|
Thermata is demonstrating a collector system with enhanced optical tracking capability. The unit includes a control system that provides real-time information to adjust the location of the reflected sunlight. It demonstrates a prototype heliostat system that meets the cost, performance, and reliability objectives of the SunShot Initiative.
The research team is working to demonstrate that a heliostat system using Thermata's innovative closed-loop optical tracking technology can satisfy key technical requirements, including total optical error and wind-load requirements.
Thermata's transformative concept is an innovation in closed-loop tracking. A camera system mounted on the central-receiver tower optically senses the focus of each individual heliostat and uses end-to-end closed-loop control to accurately place the sun on any receiver target. These breakthroughs also result in reduced mechanical tolerance requirements, lower wind forces on mechanical parts, and significant reductions in both installation and operations costs. In addition, Thermata's heliostat is controlled through a wireless mesh network, is self-powered by photovoltaics, and is factory prewired, which eliminates field wiring, trenching, and related costs.
|Advanced Manufacture of Reflectors|
University of Arizona
The University of Arizona and its partners are developing technology to improve the optical accuracy and reflectivity of the self-supporting glass mirrors used in CSP collector systems.
The research team is working to optimize and validate a novel glass-molding technique that creates very precise mirrors in a variety of shapes. The focus is on developing a novel hot-glass molding process that could be used for high-speed production at low cost, which could also be easily integrated into a production line. In parallel, the research team is developing a novel way to boost second-surface silver reflectivity and inhibit soiling.
If successful, this major advance in the method for shaping float glass could reduce the time needed for the shaping step by a factor of 100—down to 200 seconds. In this way, the process would be compatible with mass production at high speed and low cost.
|High-Performance Nanostructured Coating|
University of California San Diego
The University of California San Diego is developing a new low-cost and scalable process for fabricating spectrally selective coatings (SSCs) to be used in solar absorbers for high-temperature CSP systems.
The research team is working to demonstrate a refractory, nanoparticle-based coating that can achieve an effective solar absorptance greater than 94% and an effective infrared emittance lower than 7% at 750°C. This enables high thermal conversion efficiencies (≥ 90%) and increased temperature ranges for heat-transfer fluids (≥ 650ºC).
This research employs the novel use of surface-protected semiconductor nanoparticles, which are fabricated by a highly scalable particle synthesis method with desired size distributions. By engineering the material properties and morphologies of the nanoparticle coating, the proposed SSCs simultaneously possess the metrics of high performance, low cost, and high-temperature durability.
|La Jolla, California|