Learn more about NREL's capabilities in collector/receiver characterization.
Collector research at NREL focuses on developing and testing the next generation of concentrating solar power (CSP) collectors that reduce delivered electricity costs by 50%. NREL's work involves improved reflector development, optical model development, optical measurement techniques, testing standards, and reliability assessments. NREL also works to upgrade and adapt optical tools to enhance laboratory testing capabilities.
CSP collectors capture the sun's energy with mirrors that reflect and focus the sunlight onto a receiver, creating the heat that is used to generate electricity.
Opportunities and Potential Impact
Collectors—whether for parabolic trough, power tower, or dish systems—comprise up to 40% of the total system costs for CSP technologies. Reducing the cost of CSP systems involves improved collector designs and advanced optical materials that have low cost, high performance, and good durability.
NREL has worked with manufacturers and plant owners to identify and resolve performance issues with existing parabolic trough collectors and to ensure that lower-cost designs maintain high performance. NREL is also working on innovative, low-cost heliostat fields to reduce the delivered electricity cost of power towers.
NREL's optical materials research is aimed at developing new reflector and absorber materials and improving the long-term durability and cleanability of these materials. Two significant factors in the maintenance costs and long-term functioning of CSP technologies are the loss of performance from surface soiling and the cost to clean the surfaces. For example, reduced reflectivity of solar mirrors due to soiling can lead to an 8% to 12% drop in performance between cleanings. Addressing soiling and cleaning issues is a critical requirement for deploying CSP plants on a massive scale in low-water desert environments.
Current Research Projects and Our Innovation
NREL's research on collectors focuses on several key areas:
- State-of-the-art reflector materials—Identifying and developing materials that are low cost and able to maintain greater than 95% specular reflectance for 30 years under severe outdoor environments.
- Low-cost heliostats for modular systems—Developing and expanding a novel heliostat system with lightweight structural components, wireless control, and rapid calibration.
- Enhanced modeling platform for power tower optimization—Developing codes to address the performance and layout requirements for power tower systems and evaluating the optical performance of CSP collectors.
- Advanced measurement techniques—Developing and improving rapid techniques to assess the optical performance and heat loss of concentrating collectors and collector fields.
- Durability testing—Testing mirror samples provided by industry to determine the lifetime of solar reflector materials and to support the commercialization of CSP systems.
- Service-lifetime foundations and methodologies—Developing scientifically robust methods to predict service lifetimes for collector coatings and reflector materials that will be integrated in the development of advanced materials and system designs.
Competitively Funded Project
NREL has won a competitive DOE award to fund the following project:
- Next-generation solar collectors for CSP
Facilities and Capabilities
- Optical Characterization Laboratory—A facility that is used to measure optical and mechanical properties of potential solar materials for more than 25 years.
- Durability Testing Research Facilities—A facility with advanced capabilities to test the durability of solar materials over time using outdoor exposure test sites and accelerated exposure test chambers.
- Large-Payload 2-Axis Tracker—A device with highly accurate and automated open- and closed-loop tracking.
- Thin-Film Deposition Research Facilities—Equipment allowing NREL to develop advanced solar-selective and reflective coatings and to partner with industry to build prototypes and commercialize advanced selective coatings.
- Ultra-Accelerated Outdoor Testing—A system that simulates the harmful long-term effects of sun damage on outdoor products (such as coatings and paints) in just months, rather than decades.
- High-Flux Solar Furnace—A furnace in which NREL exposes, tests, and evaluates many components, including collectors, receivers, and high-temperature materials and coatings in an extreme solar environment.
- Distant Observer—An innovative technique to evaluate the accuracy of large fields of collectors.
- Video Scanning Hartmann Optical Tester (VSHOT)—A system enabling rapid, high-accuracy measurements of reflector shapes in both laboratory and field environments.
- Solar Optical Fringe Alignment Slope Technique (SOFAST) Laboratory—A technique to measure the mirror surface slope and collector performance during installation and operation to maintain optimum performance during operation.
- SolTrace—An NREL tool for optical modeling of CSP applications.
- Advanced Systems Analysis Program (ASAP)—Generic optical analysis software with a flexible interface.
Through innovative research and unique experience, facilities, and capabilities, NREL is working to accomplish the goal of the U.S. Department of Energy's SunShot Initiative to make installed large-scale solar energy systems cost-competitive with other energy sources by 2020.