Parabolic troughs and dry-cooled towers deliver similar value for concentrating solar power (CSP) plants, despite different solar profiles, a new report by the Department of Energy's National Renewable Energy Laboratory (NREL) has found.
The report found that the value of delivered energy of dry-cooled tower and parabolic-trough CSP plants – integrated with thermal energy storage – is quite similar.
Parabolic troughs and power towers both concentrate sunlight onto a heat-transfer liquid, which is used to drive a steam turbine. Equipped with a thermal storage capability, such as molten salt, CSP plants can generate electricity for some hours after sundown.
‘In our study, we analyzed various plant configurations and identified specific ones that provide significantly more value than has been found in previous analyses,’ says Jennie Jorgenson, NREL analyst and lead author of the report. ‘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.’
NREL is currently undertaking a similar analysis looking at the value of multiple CSP configurations in California under an assumed 40% penetration of renewables within that state.
‘For both conventional and renewable energy systems, low levelized cost of energy does not necessarily reflect these systems' total value to the grid,’ Jorgenson says. ‘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 full report can be found here.