Concentrating solar power (CSP) facilities with thermal energy storage are proving more valuable since they can serve as more of a base-load solar power plant than a photovoltaic array. That’s the conclusion of a new report from the National Renewable Energy Laboratory (NREL). The report found that CSP systems, whether tower or parabolic-trough systems, provided additional benefits to the grid rather than just the clean energy they produce.
“Unlike photovoltaic energy, CSP can generate electricity not just when the sun is shining, but also after sundown, because a CSP plant can be built with thermal energy storage, such as molten salt,” NREL said. As such it can operate more like a coal or natural-gas fired power plant by delivering base load power.
"In our study, we analyzed various plant configurations and identified specific ones that provide significantly more value than has been found in previous analyses," said NREL Analyst Jennie Jorgenson, the lead author of the report, "Estimating the Performance and Economic Value of Multiple Concentrating Solar Power Technologies in a Production Cost Model.” "For example, we explored the potential benefits of extending thermal storage at CSP plants beyond six hours, a typically modeled amount. In this analysis we found additional benefits for six to nine hours of storage, but rapidly diminishing benefits for greater than nine hours of storage."
The report also found that planning tools such as production cost models can be used analyze CSP plants. "For both conventional and renewable energy systems, low levelized cost of energy does not necessarily reflect these systems' total value to the grid," Jorgenson added. "So, providing tools that utilities and grid operators are familiar with can lead to more informed decision-making as greater levels of renewable energy penetrate the market."
The report, which looked at CSP systems in Colorado, concluded that parabolic-trough based CSP plants may cost more because they need to be larger but they still provide roughly the same value as a solar tower system. It also concluded that sizing a plant to provide more than nine hours of power without sunlight was not as cost effective and that plants that are smaller can more quickly react to the grid’s energy needs.
The lab is doing further studies on CSP technologies and is investigating the value of multiple CSP configurations in California assuming that renewables make up 40 percent of the state’s energy supply.Tweet