National Renewable Energy Laboratory

Concentrating Solar Power Research

Modeling and Analysis

NREL has the following capabilities, which include software development, for modeling and analyzing a variety of concentrating solar power technologies:

Solar Resource Maps
Optical Analysis and Modeling
Advanced Coatings Modeling and Analysis
Computational Fluid Dynamics (CFD)
Systems Analysis
Concentrating Solar Deployment System
Job and Economic Development Impact (JEDI)

This map, developed by NREL, provides a concentrating solar power siting analysis of the southwestern United States.

Solar Resource Maps

Three solar map options are available for concentrating solar power.

• Direct-Normal Solar Radiation Map of the U.S. Southwest (PDF 2.2 MB): This map covers all or part of the southwestern states of Arizona, California, Colorado, Nevada, New Mexico, Texas, and Utah. The map is an unfiltered version of the direct-normal data.

• Filtered Direct-Normal Solar Radiation Maps for the U.S. Southwest States: We have developed direct-normal solar radiation maps for the U.S. Southwest that apply filters on the following attributes: solar resource (excludes areas below 6.0 kWh/m²/day), land availability (excludes national parks and other areas off limits to development), and land slope (excludes land having slopes >1% or >3%). This approach identifies the most economically suitable lands available for deploying large-scale CSP plants. Development of these maps was supported by NREL's Geographic Information Systems (GIS) team.

• Solar Power Prospector Tool: This interactive mapping tool allows you to examine, distribute, and analyze solar resource data for the United States and northern Mexico. It assists in making decisions about optimal locations for CSP plants. You can explore temporal and spatial aspects of NREL's solar resource data and can download the resource data for use outside of the tool—for example, in the Solar Advisor Model.

Optical Analysis and Modeling

NREL has developed SolTRACE—optical modeling code software—to model solar power optical systems and analyze their performance. Researchers can even use SolTRACE for new, complex solar optical designs that previously couldn't be modeled.

SolTRACE has been used to model hardware installed at NREL's High-Flux Solar Furnace. This particular model used a single tracking heliostat element, 25 primary concentrator elements, and a single secondary concentrator element.

Using SolTRACE, we can rapidly display and save data as scatter plots, flux maps, and performance graphs. It can model optical geometry as a series of stages composed of optical elements that possess certain attributes, such as shape, contour, and optical quality. SolTRACE can model any number of stages containing any number of different elements. It features an extensive variety of available shapes and contours.

SolTRACE software requires a Windows 2000 operating environment.

Advanced Coatings Modeling and Analysis

Our experimental work in modeling and analyzing high-temperature solar selective coatings focuses on:

• Depositing the modeled coatings
• Obtaining data to validate predictions and estimates
• Reoptimizing the coating to meet the desired specifications.

We employ Essential Macleod software to design and analyze optical thin films. It enables a user to:

• Synthesize designs or refine existing ones
• Investigate errors
• Extract optical constants of film materials for use in optical coating design.

The software also can evaluate many optical thin films—including WDM and DWDM filters—and handle a wide range of performance parameters from ultrafast to color.

Computational Fluid Dynamics (CFD)

This image, developed using Computational Fluid Dynamic software, shows airflow over a multifaceted heliostat design.

We use Computational Fluid Dynamic (CFD) software to model flow and heat transfer applicable to the design of components for solar applications. FLUENT—an unstructured, finite volume-based solver—is a world-leading CFD code for a wide range of flow modeling applications. We have used CFD to model the following:

• Cooling for concentrating photovoltaic modules
• Heat transfer in pin-fin and recuperator assemblies for hybrid heat pipe designs
• Temperature profiles in thermocline storage tanks
• Wind loads on concentrator structures.

Systems Analysis

Solar Advisor Model

NREL, partnering with the U.S. Department of Energy's Solar Energy Technologies Program and Sandia National Laboratories, developed the Solar Advisor Model (SAM). This model supports the implementation of projects within the program, and also supports industry calculations of the cost of energy.

The Solar Advisor Model—a comprehensive solar technology systems analysis model—allows users to investigate the impact of variations in physical, cost, and financial parameters to better understand their impact on key figures of merit. Figures of merit related to the cost and performance of these systems include, but are not limited to, the following:

• System output (hourly, monthly, and annual)
• Peak and annual system efficiency
• Levelized cost of electricity
• Net present value
• System capital costs
• System operating and maintenance (O&M) costs.

For more information, see the following NREL documents related to SAM: "Sensitivity of Concentrating Solar Power Trough Performance, Cost and Financing with Solar Advisor Model" (PDF 909 KB) and "Modeling Photovoltaic and Concentrating Solar Power Trough Performance, Cost, and Financing with the Solar Advisor Model" (PDF 373 KB).

You can download the current version of SAM, which contains a parabolic trough system. A version of SAM for dish/Stirling systems will be available later this year. Power tower and linear Fresnel systems will be available in the future, as well.

Concentrating Solar Deployment System (CSDS)

NREL has developed the Concentrating Solar Deployment System (CSDS) Model, which examines the market penetration of concentrating solar power under various research and development. and policy scenarios. This model captures the market issues of transmission and resource variability primarily by using a much higher level of geographic disaggregation than other models and a detailed analysis of ancillary services.

With a high level of geographic disaggregation, we can model geographic variations more directly within the model. The geographic disaggregation of solar resources allows CSDS to calculate transmission distances and the benefits of dispersed solar plants supplying power to a demand region.

CSDS is an extension to the pre-existing WinDS (Wind Deployment System) model and detailed information on the underlying model and structure on NREL's Energy Analysis Web site.

Job and Economic Development Impact (JEDI)

NREL's Strategic Energy Analysis and Applications Center has developed several Job and Economic Development Impact (JEDI) models that are easy-to-use, spreadsheet-based tools. The JEDI models estimate the economic impacts of constructing and operating power generation plants at the state level.

First developed in 2002 to model wind energy development impacts, JEDI has been expanded to offer more technologies, including concentrating solar power. Running in Excel, users download the appropriate JEDI model and enter basic information about a project, including: the state, location, year of construction, and facility size. Using these data, the model then estimates the following:

• Project costs (i.e., specific expenditures)
• Economic impacts from
  • Jobs
  • Earnings (i.e., wages and salary)
  • Output (i.e., value of production).

More information on the models, how to download them, and their applications are available on the JEDI Web page.