SETO FY2018 – Concentrating Solar-Thermal Power

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The Solar Energy Technologies Office Fiscal Year 2018 (SETO FY2018) funding program addresses the affordability, flexibility, and performance of solar technologies on the grid. This program funds early-stage research projects that advance both solar photovoltaic (PV) and concentrating solar-thermal power (CSP) technologies and supports efforts that prepare the solar workforce for the industry’s future needs.

On October 23, 2018, the U.S. Department of Energy announced it would provide $53 million in funding for 53 projects in the SETO FY2018 funding program. Of those projects, 15 will focus on CSP research and development. Read the announcement. On March 22, 2019, an additional $28 million in funding was announced for 25 projects, 6 of which will focus on CSP research and development.

Approach

Projects in the CSP research and development topic support progress toward achieving a 50% cost reduction by 2030 and will focus on advancing components found in CSP sub-systems, including collectors, power cycles, and thermal transport systems, while pursuing new methods for introducing innovation to CSP research.

Objectives

Projects in this funding program will strengthen the innovation ecosystem across the country and work toward achieving the office’s 2030 cost targets. Technical projects will work toward developing new technologies and solutions capable of lowering solar electricity costs for CSP.

Selectees

-- Award and cost share amounts are subject to change pending negotiations --

Small Innovative Projects in Solar (SIPS): Concentrating Solar Power 

Lucent Optics, Inc.

Project Name: Flat Focusing Mirrors for Concentrating Solar Power
Location: Sacramento, CA
DOE Award Amount: $400,000
Cost Share: $100,000
Principal Investigator: Sergey Vasylyev
Project Summary: To reduce the cost and improve the performance of concentrating solar power (CSP) plants, Lucent Optics will investigate the feasibility of making flat focusing mirrors using a thin light-focusing film (LFF) on a planar reflective substrate. The team will produce a fully functional pilot-prototype of a flat focusing mirror measuring 0.5 meters by 0.5 meters that can be scaled to full-size CSP collectors. Planar focusing mirrors that use LFF can replace many types of traditional CSP collectors, providing a new pathway for further CSP cost reduction and performance improvement.

Sundog Solar Technology

Project Name: Development of a Front-Surface CSP Reflector Using Ultra-Barrier Technology    
Location: Arvada, CO
DOE Award Amount:  $321,000
Cost Share: $81,000        
Principal Investigator: Randy Gee
Project Summary: Sundog Solar Technology and its project partners, Helicon Thin Film Systems, Erickson International, and the National Renewable Energy Laboratory, will develop a high-performance, lower-cost solar reflector for concentrating solar power (CSP) systems. The design of this new reflector moves the silver from the back of the glass to the front of it, allowing for more efficient reflection without sacrificing product lifetime. The reflector will also have a novel coating that can withstand both ultraviolet radiation from the sun and impact from scrubbing the mirrors clean. High-volume manufacturability is critical to achieving low costs, so this reflector will be constructed using roll-to-roll manufacturing methods. The team will start by creating laboratory-scale reflector specimens and then develop the manufacturing techniques for these reflectors.

Dartmouth College

Project Name: Thermodynamically Stable, Plasmonic Transition Metal Oxide Nanoparticle Solar Selective Absorbers Towards 95% Optical-to-Thermal Conversion Efficiency at 750° Celsius
Location: Hanover, NH
DOE Award Amount: $400,000
Cost Share: $100,000     
Principal Investigator: Jifeng Liu
Project Summary: This project aims to achieve an optical-to-thermal conversion efficiency of 95% for concentrating solar-thermal power receivers using a spray-coated solar selective coating. Specifically, plasmonic metal oxide nanoparticles are thermodynamically stable at 750° Celsius and will be used to improve the coupling of incident light with the metal’s electrons, thereby improving receiver efficiency. The team will test whether optimizing the plasmonics response of transition metal components increases the optical-to-thermal conversion efficiency to 95%. The project will break through the current efficiency limit of about 89% and resolve deterioration issues in high-temperature solar absorbers without increasing the costs.

Purdue University 1

Project Name: Mitigation of Molten Salt Corrosion
Location: West Lafayette, IN
DOE Award Amount: $400,000
Cost Share: $100,000     
Principal Investigator: Kenneth Sandhage
Project Summary: When molten chloride salts are used for high-temperature heat transfer and storage, structural metal alloys and ceramic composites, the materials used to store many tons of molten salt, can experience corrosion at high temperatures if the chlorides are contaminated with dissolved oxygen or water vapor. Corrosion is the most likely source of failure for chloride salt heat transfer fluids in a concentrating solar-thermal power (CSP) system. This project aims to dramatically reduce corrosion for CSP systems by developing novel chemistries of the molten chloride salts, and will show that minimal corrosion can be achieved with appropriate containment materials.

Purdue University 2

Project Name: Mechanically, Thermally, and Chemically Robust High-Temperature Ceramic Composites
Location: West Lafayette, IN
DOE Award Amount: $400,000
Cost Share: $100,000
Principal Investigator: Kenneth Sandhage
Project Summary: The purpose of this project is to increase the thermal-to-electrical conversion efficiency of concentrating solar power systems by developing new mechanically robust, thermally conductive, and thermally cyclable ceramic composites used to make chloride salt heat exchangers and piping. Currently, no cost-effective solution exists for either of these components at high temperatures. These composites will be stiffer and stronger than nickel-based superalloys at 550° to 750° Celsius and also resistant to corrosion by supercritical carbon dioxide air, and heat transfer and storage fluids, such as molten chlorides. The team will also test the manufacturability of these robust ceramic composites in complex shapes via scalable, low-cost forming and thermal treatments.

University of California, San Diego

Project Name: High-Entropy Ceramic Coatings: Transformative New Materials for Environmentally Compatible Thin-Film Insulators against High-Temperature Molten Salts 
Location: La Jolla, CA
DOE Award Amount: $400,000
Cost Share: $100,000
Principal Investigator: Jian Luo
Project Summary: This project will develop high-entropy ceramics (HEC) as a new type of insulating and protective coating material for metal alloys used in high-temperature piping and containment. HEC is a class of materials made up of several elements in relatively equal proportions, whereas typical ceramics and alloys are made up of one or two predominant elements. An effective, low-cost protective coating like HEC could substantially reduce the need for expensive, high-temperature superalloys. In order to develop and select the best material, the team will measure thermal conductivities of HEC compositions and examine their stabilities against molten nitrate, carbonate, and halide salts. This will optimize HEC composition and processing, helping to further reduce their thermal conductivities, which increases performance in high-temperature environments and lowers costs.

Virginia Polytechnic Institute and State University 1

Project Name: Durable and Low-Cost Fractal Structured Multifunctional Coatings for Next Generation CSP
Location: Blacksburg, VA
DOE Award Amount: $399,991
Cost Share: $100,102
Principal Investigator: Ranga Pitchumani
Project Summary: This project team will develop fractal-textured barrier coatings for conventional, low-cost alloys like stainless steel to protect against corrosion from supercritical carbon dioxide, molten chloride, and carbonate salts used in concentrating solar power (CSP) plants. Multiscaled, fractal textured surfaces can be fabricated directly on the underlying material using a process called electrodeposition, helping to create a robust and durable coating that preserves the thermal properties of the substrate. The textured surfaces of the coating will prevent wetting of the corrosive fluids with the surface, leading to a lower power requirement to pump fluids, less corrosion and wear, and reduced heat loss. This will help to increase the overall efficiency and lifetime of a CSP plant.

University of Utah

Project Name: Volumetrically Absorbing Thermal Insulator For Monolithic High-Temperature Microchannel Receiver Modules
Location: Salt Lake City, UT
DOE Award Amount: $400,000
Cost Share: $100,000
Principal Investigator: Sameer Rao
Project Summary: The thermal efficiency of concentrating solar power receivers is limited by optical and thermal losses. This project will develop a novel, low-cost, high-temperature, and chemically stable receiver design, based on a porous matrix of refractory ceramics, that can absorb concentrated solar light throughout its 3-dimensional volume. This design can potentially substantially reduce optical and thermal losses relative to the 2-dimensional surface of the tubes that are currently used as receivers. The team will develop a high-performance receiver that operates at over 720° Celsius, has a thermal efficiency rate above 92%, and maintains excellent thermo-mechanical and thermo-chemical stability. The team will validate the design through computations and then experimentally at the lab-scale.

University of Michigan 1

Project Name: Robust and Spectrally-Selective Aerogels for Solar Receivers
Location: Ann Arbor, MI
DOE Award Amount: $260,000
Cost Share: $65,000
Principal Investigator: Andrej Lenert
Project Summary: Efficient conversion of sunlight at high temperatures requires both absorption of sunlight and retention of heat from escaping in the form of radiation, convection, and conduction. The team will develop a transparent, thermally insulating aerogel cover that enables a concentrating solar thermal-power receiver to operate more efficiently at high temperatures. This aerogel cover would be transparent to sunlight and able to absorb thermal radiation. The proposed aerogel wouldn’t require selective surfaces or a vacuum for attachment and would enable better thermal resistance at high temperatures. The aerogel cover will be developed and tested in order to minimize thermal losses and improve thermal stability.

Advanced CSP Collectors

SolarReserve, LLC

Project Name: HelioSR3 - Fully Autonomous Heliostat System for SolarReserve Exceeding Gen3 Targets
Location: Santa Monica, CA
DOE Award Amount: $2,000,000
Cost Share: $500,000     
Principal Investigator: David Haas
Project Summary: SolarReserve aims to create HelioSR3, a new heliostat system that aims to lower costs and improve the performance of solar collectors in concentrating solar-thermal power systems that use power towers. SolarReserve will work with partners in academia to develop the new smaller heliostat, which will experience lower wind loads and result in lower loss of light from the collector field and reduced installation costs. SolarReserve will also work with the National Solar Thermal Test Facility at Sandia National Laboratories to optimize the optical properties and enhance other capabilities of the smaller heliostats, including automated calibration and alignment, tracking error corrections, and self-diagnostics.

University of Tulsa

Project Name: Development of a Microvascular Power Tower Receiver Using a Carbon Composite
Location: Tulsa, OK
DOE Award Amount: $1,277,345               
Cost Share: $319,337
Principal Investigator: Michael Keller
Project Summary: This project will develop and characterize a novel material and fabrication method that can be used in advanced concentrating solar-thermal power receivers. To enhance the transfer of thermal energy from the sun into the heat transfer fluid, the team will create a polymer-fiber composite that integrates microchannels within the material to form a light-weight, highly absorptive material. The team will form channels within a composite material and then add carbon to it to create a mechanically robust carbon-carbon composite that has an absorptivity of 95-96% without the application of an additional coating. Compared to steal or nickel alloy receiver systems, the proposed system could lower manufacturing costs, increase higher heat transfer efficiency, and provide mechanical reliability at temperatures well above 700° Celsius.

Edisun Microgrids

Project Name: Design and Develop a Novel Heliostat Gear System and Supporting Field Control System
Location: Pasadena, CA
DOE Award Amount: $1,234,084               
Cost Share: $320,000
Principal Investigator: Steve Schell
Project Summary: Heliostats are nearly flat mirrors that track the sun and concentrate the sunlight onto a fixed target atop a tower, called a receiver, in order to generate heat that’s used in concentrating solar thermal power (CSP) plants. A utility-scale power tower CSP system could have more than 100,000 heliostats. The efficiency of this collector field is determined by how well each heliostat tracks the sun and maintains accuracy even when it’s windy. Traditional cost reduction strategies have focused on developing larger heliostats with more mirror surface area on each unit, making the mirrors even more susceptible to wind. This project will pair smaller mirrors that can more precisely track the sun with an inexpensive novel gear train as the foundation of the heliostat. The team will also develop and test a monitoring and tracking system to ensure each of the heliostats is performing as expected.

Advanced Power Cycles for CSP

University of California, Davis

Project Name: Additively-Manufactured Molten Salt-to-Supercritical Carbon Dioxide Heat Exchanger
Location: Davis, CA
DOE Award Amount: $2,219,315
Cost Share: $582,988     
Principal Investigator: Vinod Narayanan
Project Summary: This team seeks to develop an additively manufactured, nickel superalloy primary heat exchanger (PHX) for advanced molten salt concentrated solar-thermal power (CSP) systems. The PHX will be made using nickel superalloys and laser powder bed 3-D printing, resulting in a compact design that is durable under cyclic operation at high temperatures and pressures in a corrosive salt environment. During the first phase of the project, different alloy powders will be fabricated and characterized and then tested, both in conditions representative of Generation 3 CSP systems—720° Celsius and supercritical carbon dioxide pressures of 200 bar—and at conditions relevant to current commercial systems—molten nitrate salt at temperatures up to 550° Celsius. The team aims to validate a thermal model that can predict performance in a chloride salt environment and plans to use this model to develop a 20-kilowatt design to test the mechanical integrity of the fabricated PHX. 

CompRex, LLC

Project Name: 740H Diffusion Bonded Compact Heat Exchanger for High Temperature and Pressure Applications
Location: De Pere, WI
DOE Award Amount: $1,242,525
Cost Share: $317,174
Principal Investigator: Zhijun Jia
Project Summary: There is growing demand for high-temperature, high-pressure heat exchangers that can meet the stressful operating requirements of novel supercritical carbon dioxide Brayton cycles systems in a way that’s cost-effective at commercial scale. CompRex has developed a heat exchanger design using 740H, a new alloy that can endure significantly higher stress at temperatures over 700° Celsius, making it ideal for use with supercritical carbon dioxide cycles. In collaboration with Special Metals, the University of Wisconsin-Madison, and Advanced Vacuum Systems, CompRex seeks to develop a manufacturing process for producing 740H printed circuit heat exchangers using its proprietary ShimRex® flow path design. This design will address the challenges that the material poses in etching and diffusion bonding that prevent the cost-effective manufacturing of 740H heat exchangers.

GE Global Research 1

Project Name: Additively Manufacturing Recuperators via Direct Metal Laser Melting and Binder Jet Technology
Location: Niskayuna, NY
DOE Award Amount: $1,400,000                               
Cost Share:
$350,000
Principal Investigator: William Gerstler
Project Summary: This team will develop additive manufacturing processes for the heat exchangers used in supercritical carbon dioxide (sCO2) power cycles in concentrating solar-thermal power plants. To overcome the expensive manufacturing process for heat exchangers, the team will use binder jet printing, a type of additive manufacturing, to significantly lower costs and enable new heat exchanger geometries, such as 3-D channels, and curved features not accessible using traditional fabrication processes. The team will then evaluate the new process and determine if it’s capable of producing CSP compatible power cycles that cost $900 per kilowatt or less. The team will also perform mechanical tests to ensure that the resulting heat exchangers can withstand the high operating temperatures and pressures of the sCO2 power cycle. The team will also create a risk reduction plan for scaling the heat exchanger design from lab-scale to a full-scale, including, a modular design.

GE Global Research 2

Project Name: Gas Lubricated Bearings for Drivetrain in sCO2 Cycle
Location: Niskayuna, NY
DOE Award Amount: $2,373,442                                               
Cost Share:
$593,361
Principal Investigator: Jason Mortzheim
Project Summary: This project will de-risk a novel bearing design for the turbines used in concentrating solar-thermal power (CSP) plants with supercritical carbon dioxide (sCO2) power cycles. The bearing is a critical component that ensures the turbine, which converts heat into mechanical energy, performs reliably and at a high efficiency level. The turbine is the greatest single contributor to the sCO2 cycle’s efficiency. These bearings must be durable and able to withstand the high temperatures and pressures associated with next generation sCO2 power cycles. The team will then perform mechanical tests and simulate rotor tests in order to optimize the design for CSP plants that provide consistent baseload power or operate as a rapidly-responding peaker plant. The team will perform technoeconomic analysis to determine if the design can achieve a 50% efficient power cycle in order to lower costs to $.05 per kilowatt-hour.

Southwest Research Institute 1

Project Name: Development of a High-Efficiency Hybrid Dry Cooler System for sCO2 Power Cycles in CSP Applications
Location: San Antonio, TX
DOE Award Amount: $1,550,000                                               
Cost Share:
$387,500     
Principal Investigator: Tim Allison
Project Summary: This project aims to develop a compact dry cooling heat exchanger for supercritical carbon dioxide (sCO2) power cycles in concentrating solar-thermal power (CSP) plants. Dry cooling drastically reduces the water used by power plants. However, it can reduce the thermal-to-electric conversion efficiency of the power cycle. An efficient heat exchange between sCO2 and ambient air can both conserve water while maintaining peak power cycle performance. The team will create and optimize a dry cooling heat exchanger with microchannels on the sCO2 side and a geometry that uses plates and finned chambers on the air side. The team will test the dry cooling system at the megawatt-scale with an sCO2 test loop, in order to determine the reliability of the fabrication method, validate the performance of the heat exchanger geometry, and show that the new dry cooling concept is compatible with an efficient CSP plant. These improvements could reduce the cooler cost from $168 per kilowatt to $95 per kilowatt and reduce cooling power consumption in CSP plants by 14%.  

Southwest Research Institute 2

Project Name: High-Temperature Dry-Gas Seal Development and Testing for sCO2 Power Cycle Turbomachinery
Location: San Antonio, TX
DOE Award Amount: $2,000,000                               
Cost Share:
$500,000     
Principal Investigator: Jason Wilkes
Project Summary: Concentrating solar-thermal power (CSP) plants with supercritical carbon dioxide (sCO2) power cycles requires a mechanical seal to prevent working fluid leaks and support efficient operations. The increased temperatures and pressures of the sCO2 power cycle requires a novel seal design to support a target thermal-to-electric power conversion efficiency of 50%. This project will develop a high-temperature dry gas seal (DGS) by replacing the temperature sensitive elements with more durable components, enabling the DGS to reach operating temperatures over 500° Celsius and enable the higher efficiency levels. Because the DGS design would also be significantly smaller in size, the DGS would reduce the complexity of the sCO2 turbine design, helping to increase operation reliability and improve turbine efficiency.

Advanced CSP Thermal Transport System and Components

Colorado School of Mines 1

Project Name: Narrow-Channel, Fluidized Beds for Effective Particle Thermal Energy Transport and Storage
Location: Golden, CO
DOE Award Amount: $1,858,170
Cost Share: $464,712
Principal Investigator: Gregory Jackson
Project Summary: Using particles to replace the heat transfer fluid in a concentrating solar-thermal power (CSP) system may be the simplest way to increase the operation temperature and therefore increase the power cycle efficiency of a CSP plant. Colorado School of Mines will work with Sandia National Laboratories and Carbo Ceramics to develop and test a narrow-channel, counterflow fluidized bed receiver and heat exchanger designs. These will be used to analyze flow conditions and improve heat transfer rates in the receiver and heat exchanger. The team will then use these insights to test a modular panel for an indirect particle receiver and/or particle to supercritical carbon dioxide power cycle heat exchanger. The program will deliver detailed multiphase flow modeling tools to assess how receiver and heat exchanger designs can meet receiver cost targets of $150 per kilowatt hours of heat and thermal-energy system targets of $15 per kilowatt hours of heat.

Virginia Polytechnic Institute and State University 2

Project Name: Fractal Nanostructured Solar Selective Surfaces For Next Generation Concentrating Solar Power
Location: Blacksburg, VA
DOE Award Amount: $903,045
Cost Share: $225,764
Principal Investigator: Ranga Pitchumani
Project Summary: This project aims to increase the thermal efficiency of solar receivers by fabricating multiscale fractal nano- and micro-structured high-temperature coatings that can be applied to the receiver in a concentrating solar-thermal power system. Called a selective solar surface, this multiscale surface has texturing, which could enable the coating to enhance light trapping in the solar receiver, improve energy absorption, and eliminate the need for anti-reflection coatings. The team seeks to develop durable solar selective surfaces that enable absorption efficiency rates greater than 90% at temperatures higher than 750° Celsius, and with a degradation rate of less than .2% per 1,000 hours.

University of Arizona

Project Name: Sensing and Arresting Metal Corrosion in Molten Chloride Salts at 800° Celsius
Location: Tuscon, AZ
DOE Award Amount: $800,000
Cost Share: $200,000
Principal Investigator: Dominic Gervasio
Project Summary: This team proposes new approaches to mitigating corrosion from molten chloride salts in concentrating solar-thermal power systems. This project will investigate the potential of using metal salt additives to slow the loss of specific metals from piping; zirconium metal structures to remove impurities in the molten salt loop; and novel corrosion warning and controlling devices that can detect corrosion and switch salt flows. If successful, this project will show the feasibility of multiple new methods for sensing and stopping corrosion in advanced molten chloride salts for next-generation concentrated solar-thermal power thermal transport systems.

Learn more about the SETO FY2018 funding program and the projects selected for the photovoltaics and workforce initiative topics.