These 25 Advanced CSP & CST Technologies to Share $33 Million US DOE Funding

Solar reactors for high-temperature thermochemistry are among the breakthrough technologies to receive US DOE funding IMAGE@ Aldo Steinfield ETH: A two-step solar thermochemical CO2-splitting cycle using Zn/ZnO redox reactions

The Solar Energy Technologies Office Fiscal Year 2021 Photovoltaics and Concentrating Solar-Thermal Power Funding Program (SETO FY21 PV and CSP) funds research and development projects that advance PV and CSP to help eliminate carbon dioxide emissions from the energy sector.

On October 12, 2021, SETO announced that 40 projects were awarded $40 million. Twenty-five of those projects will receive almost $33 million to research and develop CSP technologies that help reduce costs and enable long-duration solar energy storage and carbon-free industrial processes in the United States. Read about the SETO FY21 PV projects.


Projects will work to:

  • Advance novel solar receivers and reactors;
  • Advance key components for pumped thermal-energy storage (PTES), such as compressors and heat exchangers;
  • Meet technoeconomic requirements for thermal energy storage, and prepare the innovations for manufacturing and commercialization;
  • Improve the reliability, operability, and productivity of systems, processes, and designs of existing CSP technologies;
  • Improve the design and operation of CSP plants by developing components and equipment for commercially relevant CSP systems that use conventional steam Rankine power cycles.

Small innovative projects in solar (SIPS) will focus on innovative and novel ideas that will dramatically lower the cost of CSP technologies to produce power or industrial heat. If successful, these technologies could move to the next stage of research and development after one year.


This funding program will help achieve SETO’s goal of lowering solar energy costs 50% by 2030 and bring solar into new markets. These projects will advance CSP components and technologies so CSP can replace fossil fuels in industrial applications; advance PTES technologies that can use electricity to charge thermal energy storage, either as standalone systems or integrated with CSP plants; advance technologies, training, and standards to reduce the costs of parabolic trough and power tower CSP plants; and help achieve a carbon-free electricity sector by 2035 and a net-zero-emissions energy sector by 2050.


— Award and cost share amounts are subject to change pending negotiations –

Topic Area 2: Scalable Outputs for Leveraging Advanced Research on Receivers & Reactors (SOLAR R&R)


Project Name: Silicon-Carbide Receiver/Reactor by Additive Manufacturing for Concentrated Solar Thermocatalysis with Thermal Energy Storage
Location: Ithaca, NY
DOE Award Amount: $2.7 million
Cost Share: $700,000
Project Summary: Dimensional Energy is partnering with Heliogen to design, develop, and test a solar-driven chemical reactor that can produce sustainable jet fuel. The reactor will turn captured carbon dioxide and green hydrogen into fuel at a target price below $2 per gallon. The team will leverage an additively manufactured silicon carbide material that is stable at temperatures greater than 1,000°C to enable this technology. The concept integrates thermal energy storage into the receiver to enable continuous operation of the reactor.


Project Name: Ultra-High Operating Temperature Silicon-Carbide-Matrix Solar Thermal Air Receivers Enabled by Additive Manufacturing (Ultra-HOTSSTAR)
Location: Niskayuna, NY
DOE Award Amount: $2.6 million
Cost Share: $900,000
Project Summary: The Ultra-HOTSSTAR project applies GE’s high-temperature manufacturing technologies to design volumetric silicon carbide (SiC) receivers to efficiently convert sunlight to thermal energy. SiC enables solar receivers to go beyond the temperature limits of metal alloys and will allow the team to design receivers appropriate for very-high-temperature industrial processes. In collaboration with Heliogen, the team will use 3D-printing to optimize promising designs by improving manufacturability, lowering cost, and validating thermo-mechanical reliability under realistic conditions.


Project Name: Light Trapping, Enclosed Planar-Cavity Receiver for Heating Particles to Enable Low-Cost Energy Storage and Chemical Processes
Location: Golden, CO
DOE Award Amount: $3 million
Cost Share: $750,000
Project Summary: This project team will design, develop, and test a 100 kilowatt solar-thermal receiver that will deliver energy to particles at temperatures greater than 700°C. The innovative approach encloses the particles in a nickel-alloy receiver, shaped to “trap the light” by preventing energy from being re-emitted back to the environment. Light trapping will be a key component of the team’s efforts to design a receiver with thermal efficiency above 90%. The team will also use a coating to prevent the receiver structure from overheating, as well as a gas to get particles to behave like a fluid inside the receiver to maximize heat transfer.


Project Name: Scalable, Infiltration-Free Ceramic Matrix Composite (CMC) Manufacturing for Molten Salt Receiver  
Location: Palo Alto, CA
DOE Award Amount: $2.5 million
Cost Share: $600,000
Project Summary: This project will develop scalable manufacturing processes for CMCs that will aim to reduce the cost of these high-temperature-stable materials by more than three times below the cost of current commercial products. To achieve this they will develop production methods that avoid steps that take a long time and use costly materials. This technology will help address the need for scalable, corrosion-resistant receiver materials compatible with high-temperature molten chloride salts.


Project Name: Intensified Solar Reactor for Green Ammonia Manufacture and Gen3 Thermochemical Energy Storage
Location: Lubbock, TX
DOE Award Amount: $2 million
Cost Share: $500,000
Project Summary: This project team will develop a solar-thermal system to enable an ammonia synthesis reactor that does not require fossil fuel input. By using a process intensification strategy, the team will design an ammonia reactor that efficiently uses heat throughout the process to drive the ammonia reaction. The ammonia can be used either as part of a closed thermochemical energy storage system, for electricity production, or to produce ammonia as a commodity chemical. In this project, the team will focus on the design and validation of their heat-recovery technology that can enable significantly higher efficiency than previous designs.


Project Name: Design and Manufacturing of Transparent Refractory Insulation for Next-Generation Receivers
Location: Ann Arbor, MI
DOE Award Amount: $2.5 million
Cost Share: $600,000
Project Summary: The University of Michigan is partnering with AeroShield to develop a manufacturing strategy for a novel aerogel material developed by the project team. This material has the potential to substantially improve the efficiency of concentrating solar-thermal power parabolic trough collectors. The aerogel is transparent to the solar spectrum, and can be modified to absorb heat that would otherwise be lost from the receiver tube. The team plans to show the aerogel can enable efficient solar-thermal energy collection at 700°C, to enable parabolic trough collectors to couple with high-temperature and high-efficiency power cycles

Topic Area 3: Pumped Thermal Energy Storage (PTES)


Project Name: Advanced Ice Slurry Generation System for a Carbon Dioxide–Based Pumped Thermal Energy Storage System
Location: Akron, OH
DOE Award Amount: $1.2 million
Cost Share: $400,000
Project Summary: Echogen will develop a heat exchanger that will reduce the cost of using ice as a cold thermal reservoir in thermal energy storage systems. The team will accomplish this by simplifying the design of existing commercial systems that mechanically scrape ice from heat-transfer surfaces. This project could improve the cost and operational complexity of efficient thermal energy storage systems that use heat pumps to convert electricity into heat for long-duration storage.


Project Name: Characterization of Inlet Guide Vane Performance for Discharge Compressor Operation near the Dome of an sCOPumped Heat Electricity Storage
Location: San Antonio, TX
DOE Award Amount: $500,000
Cost Share: $100,000
Project Summary: This project will advance the design of inlet guide vanes (IGV), which are a critical component in supercritical carbon dioxide compressors. They are used to direct fluid flow in a compressor to optimize flow over the rotating blades. This project will integrate IGVs into a compressor to collect data on fluid-flow profiles that can be used across the industry. The compressor is a key component in charging and discharging cycles for long-duration thermal energy storage.


Project Name: Development of a Multiphase-Tolerant Turbine for Pumped Thermal Energy Storage
Location: San Antonio, TX
DOE Award Amount: $2.4 million
Cost Share: $600,000
Project Summary: Southwest Research Institute will design a turbine to maximize the efficiency of a carbon dioxide–based heat pump cycle, which is a promising technology to efficiently store electricity in long-duration thermal energy storage systems. This project will optimize turbine designs that will be able to tolerate constantly shifting fluid properties, since it will interact with both liquid and gas phases within the machine. This heat-pump turbine is a critical component to enable cost-effective thermal energy storage of electricity, with potential round-trip system efficiencies above 65%.

Topic Area 4a: Process Enhancement and Refinement For Operations, Reliability, and Maintenance (CSP PERFORM)


Project Name: Improved O&M Reliability for CSP Plants through Application of Steam Generator Damage Mechanisms Theory & Practice
Location: Charlotte, NC
DOE Award Amount: $1.9 million
Cost Share: $500,000
Project Summary: This project aims to improve the reliability, operability, and productivity of concentrating solar-thermal power (CSP) plants by developing a “theory and practice” document for CSP steam generators, with input from technology end-users, such as plant operators, designers, and other stakeholders. This reference and guidance document will cover the evolution of damage in CSP steam cycle equipment and the necessary operations and maintenance practices to manage this damage. It will fully describe the mechanisms that lead to damage in each component and provide guidance on identifying issues and understanding how to manage and prevent its recurrence.


Project Name: Improved Design Standard for High Temperature Molten Nitrate Salt Tank Design
Location: Minneapolis, MN
DOE Award Amount: $2 million
Cost Share: $500,000
Project Summary: This project will develop a comprehensive design guide for thermal energy storage tanks for molten nitrate salt. The team will develop methodologies for the tank’s structural design, considering corrosion effects and other factors, and guidelines for material selection, welded joints, fatigue evaluation, the design of the tank foundation, and its leak detection systems, in addition to the effects of choosing internal versus external tank insulation. This guide could be a standard for nitrate salt tanks for developers to adopt and implement in new plant builds.


Project Name: CSP Plant Optimization Study for the California Power Market
Location: Broomfield, CO
DOE Award Amount: $1 million
Cost Share: $250,000
Project Summary: This project team will conduct a detailed systems study to determine the optimal configuration of CSP plants to support the emerging needs of the California market. Working with grid operators and utilities, like the California Independent System Operator (CAISO) and the Sacramento Municipal Utility District (SMUD), this study will evaluate the technoeconomic potential of different CSP technologies and configurations, and the key challenges preventing deployment to lower the barriers preventing CSP project development and commercialization.


Project Name: Design Basis Document/Owners Technical Specification for Nitrate Salt Systems in CSP Projects
Location: Broomfield, CO
DOE Award Amount: $450,000
Cost Share: $100,000
Project Summary: This project team will develop a design basis document for CSP systems that use nitrate salts and will make it widely available to the public. This document will collect key information on best practices and lessons learned from existing commercial CSP plants, and will provide a key tool to develop a common understanding among future power plant owners, engineering-procurement-construction (EPC) contractors, and operations and maintenance contractors. Focuses of the document will include receiver tube material decisions, avoidance of stress relaxation cracking, appropriate welding procedures, heat exchanger fabrication techniques, and heat trace design, among others. The project will engage a large portion of the CSP industry to ensure wide relevance of the document.


Project Name: Evaluation of High-Temperature Sensors for Molten Solar Salt Applications
Location: Lafayette, CO
DOE Award Amount: $1 million
Cost Share: $250,000
Project Summary: Sporian Microsystems will design and fabricate sensors for use in molten salt CSP plants. The sensors will be able to monitor flow rates, fluid pressures and chemical impurities, to ensure reliable plant operations. Sporian is teaming with three national labs to evaluate and validate the performance of these sensors. Precise measurements of molten salt flow, pressure, and chemical composition at operating temperature will provide CSP plant operators with information that can allow for enhanced control to improve performance and prolong the life of key CSP subcomponents.


Project Name: Performance Improvement in CSP Plant Operations
Location: Madison, WI
DOE Award Amount: $1.6 million
Cost Share: $500,000
Project Summary: This project will improve performance in existing CSP plants by creating a model of plant operations that will simulate real plants to allow training of CSP operators. This model will be capable of evaluating alternative operating and control strategies to improve plant performance and cost-effectiveness. CSP operators will be able to test control decisions in a low-risk but realistic model environment, which is especially beneficial for rare events that can have a significant effect on plant output. Data from operating commercial plants will be used to ensure the fidelity of plant emulation models.

Topic Area 4b: Research in Equipment For Optimized and Reliable Machinery (CSP REFORM)


Project Name: Performance Optimization of Sold Particle TES Heat Exchanger by Combining Benefit of Extended Surfaces and Particle Fluidization
Location: Hampton, NH
DOE Award Amount: $1.9 million
Cost Share: $500,000
Project Summary: Solid particles have several advantages over conventional molten nitrate salts as a heat-transfer media in CSP tower systems. For a particle system to work with a steam Rankine power cycle, new designs for particle-to-steam heat exchangers are needed. This project team will design and develop such a heat exchanger utilizing both particle fluidization and extended surface fins to maximize the heat transfer performance of the component. The team will build and test a prototype heat exchanger to validate performance models and operability.

Topic Area 5b: Small Innovative Projects in Solar (SIPS) – CSP


Project Name: Concentrated Solar Thermal Fuels Production by Electric Field Enhanced Two-Step Gas Splitting
Location: Tempe, AZ
DOE Award Amount: $300,000
Cost Share: $75,000
Project Summary: This team will develop a novel solar thermochemical cycle for the production of renewable fuels from carbon dioxide (CO2). Current concepts that thermally activate CO2 are limited by the extreme temperatures (around 1,500°C) needed to execute the reaction. The team will design a prototype reactor that applies a small voltage to cerium oxide immersed in a molten salt to generate an electric field, which lowers the required temperature for the reaction. The project targets a 600°C reduction in the COsplitting temperature, making the process feasible for integration in a concentrating solar-thermal power plant.


Project Name: Technology for Electrically Enhanced Thermochemical Hydrogen
Location: Tempe, AZ
DOE Award Amount: $400,000
Cost Share: $100,000
Project Summary: The project team will develop and test a thermo-electrochemical process to produce “green” hydrogen from steam with solar energy. This approach combines high-temperature solar-thermochemical water splitting (TCWS) with electrochemical pumping of hydrogen through a proton conducting membrane. This mitigates or eliminates many of the key challenges to implementing TCWS. The technology will enable low-cost solar-to-hydrogen efficiencies that exceed 25% (theoretical limit > 50%).


Project Name: In-Operando Thermal Transport Characterization of Moving Particle Bed Heat Exchanger
Location: San Diego, CA
DOE Award Amount: $400,000
Cost Share: $100,000
Project Summary: This project team will integrate a novel heat-transfer measurement technique into an operating 1-megawatt heat exchanger at Sandia National Laboratories. The technique measures a dynamic surface radiation signal to determine thermal transport rates at different distances from the surface. The technique will be used to observe both near-wall and bulk-particle heat-transport rates in a particle-to–supercritical carbon dioxide heat exchanger. The heat exchanger is a key component in Sandia’s Generation 3 particle pilot plant.


Project Name: High-Temperature Permanent Magnet-Biased Active Magnetic Bearing Development for Supercritical Carbon Dioxide Machinery Applications
Location: San Antonio, TX
DOE Award Amount: $400,000
Cost Share: $100,000
Project Summary: This project seeks to identify and test magnetic materials that can be used for bearings in concentrating solar-thermal power (CSP) plants that use a supercritical carbon dioxide (sCO2) power cycle and operate at temperatures higher than 540°C. The team will design permanent magnet-biased active magnetic bearings (PM-AMBs), an enabling technology for hermetic sCO2 machinery, which is expected to increase cycle efficiency. PM-AMBs may have advantages over gas bearings, including greater tolerance to misalignment, reduced wear, tunability, and diagnostic capabilities. The team will also test key materials for compatibility to exposure in a high-temperature CO2 environment. Machine layouts with PM-AMBs will be developed to demonstrate feasibility.


Project Name: Development and Experimental Optimization of High-Temperature Modeling Tools and Methods for Concentrated Solar Power Particle Systems
Location: Dayton, OH
DOE Award Amount: $400,000
Cost Share: $100,000
Project Summary: Accurately modeling flow and heat transfer of solid particles in next-generation CSP systems is challenging compared to conventional systems that use liquid heat transfer fluids. The University of Dayton will perform a variety of particle flow and heat transfer experiments to develop and validate a broadly applicable computational model that can be used by researchers working on particle-based systems. DCS Computing will integrate the validated framework into a modeling toolkit. If successful, a broad range of researchers and technology developers could use the modeling tools to study their system without further fundamental property measurements.


Project Name: Spectral and Temperature-Dependent Optical Metrology: Towards More Robust, Effective and Durable Materials for Concentrated Solar Power
Location: Ann Arbor, MI
DOE Award Amount: $200,000
Cost Share: $100,000
Project Summary: This project team will explore the impact of temperature on the optical properties of materials relevant to CSP. Traditional optical spectroscopy measurements focus on room-temperature properties, which may not be representative of properties at high temperature. This team will develop standardized spectroscopic measurement techniques, protocols, and procedures to determine radiative properties of materials. They will incorporate their data into a digitized database of optical properties and utilize both experimental data and predictive modeling tools.


Project Name: Development of Gas Bearings for Supercritical Carbon Dioxide Recompression Brayton Cycle
Location: Las Vegas, NV
DOE Award Amount: $200,000
Cost Share: $100,000
Project Summary: The project team will explore using porous graphite in the gas bearings that support the turbine shaft of supercritical carbon dioxide (sCO2) cycle turbomachinery. Gas bearings inject high-pressure gas to avoid friction caused by rotation of the turbine shaft, which lowers efficiency. They will test their bearings in a high-pressure and high-temperature CO2 gas environment to validate their performance. If successful, these bearings allow for nearly frictionless operation of the turbomachinery, minimizing wear and simplifying system operation, which would reduce maintenance costs and improve cycle efficiency.


Project Name: Innovative Technology for Continuous, Online (In Situ) Monitoring of Corrosivity of Molten Salts to Prevent Catastrophic Failure of Solar Thermal Plants
Location: Reno, NV
DOE Award Amount: $400,000
Cost Share: $100,000
Project Summary: This project team will develop and evaluate an innovative sensor for molten chloride salts based on the measuring “optical basicity,” which represents the corrosivity of the fluid. The team will develop and validate the concept, and design an online monitoring system that could be used in commercial plants.


Project Name: Low-Cost Heliostat for High-Flux Small-Area Receivers
Location: Madison, WI
DOE Award Amount: $300,000
Cost Share: $100,000
Project Summary: This project team will design a novel heliostat for small solar fields that may drastically reduce the component cost compared to commercial systems. The concept uses a two-step design in which a first stage of reflection is accomplished via a set of rotating heliostats that share a common set of tracking drives, enabling significant cost reduction. A second stage of stationary mirrors concentrates solar light on the receiver.

Learn more about the SETO FY21 PV and CSP funding program and the project selections in the other topics.

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