Reducing the water footprint of concentrating solar power plants : : techno-economic assessment of water saving solutions

Abstract: Recent years have seen a strong worldwide growth in Concentrating Solar Power (CSP) installation capacity. The cost of CSP components have been decreasing, especially after China entered the CSP market. It is expected that CSP will be able to deliver cost-competitive electricity at 0.05 $/kWh in 2030. The already cost-competitive thermal energy storage (TES) of CSP has made it an attractive technology as dispatchable clean power is essential for energy transition towards renewables. These developments could lead to an expansion of the global CSP market and an increase in the share of solar energy in the electricity market. But the environmental effects of such expansion is a matter of concern.
The use of water in CSP plants can reduce investment cost and significantly increase overall plant efficiency. Therefore, on one hand, water use can accelerate CSP growth and bring the technology closer to the target LCOE (Levelized Cost of Electricity). On the other hand, it can be challenging to find suitable sites with available freshwater resources the use of which will not negatively affect the ecosystem. The motivation of this study is to investigate technological solutions for reducing the water use of CSP plants while maintaining the efficiency of the plant and the LCOE.
One of the main objectives of this thesis is to develop suitable dynamic simulation models that can replicate the water use behavior and mechanism of a CSP plant and are validated against real plant data. This includes integrated water and wastewater streams and treatment processes throughout the plant. The simulation models are used to investigate selected innovative water saving solutions with the focus on all three major water consumers of a CSP plant: the cooling system, mirror cleaning, and steam cycle. The investigation includes benchmarking with state-of-the-art technologies, techno-economic assessment, and optimization of CSP plants for minimizing water use and reducing the LCOE.
The simulation-based study confirms that significant water saving is possible in all three sections of the plant. In the field of cooling technology, a novel hybrid concept shows a large water saving potential of up to 80% while not affecting the LCOE when the CSP plant design is optimized accordingly. In the field of mirror cleaning strategy, interesting findings indicate that an evenly-distributed reflectance over the entire solar field leads to higher heat gain. That given, an optimized cleaning schedule based on continuous monitoring of spatial distribution of soiling rate and cleanliness is developed, which decreases the water consumption by up to 19% and decreases the cost of cleaning by 25% without any negative effect on plant performance.
In addition to studying the reduction potentials of water use at component level, the potentials which lie in the way of handling the water and wastewater within the steam cycle are also analyzed. Specifically, alternative water management strategies for blowdown reuse, Zero Blowdown (ZBD), and Zero Liquid Discharge (ZLD) are considered. The study shows that a developed concept for blowdown reuse can reduce the total plant water usage by an additional 14% with no additional investment cost

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch
• Notes: Universität Freiburg, Dissertation, 2021

Classification and Topics

• Classification: Natürliche Ressourcen, Energie und Umwelt
• Keyword: Water ; Evaluation ; Solar power plants ; CSP

Contributors, Places and Time

• Event: Veröffentlichung
• (where): Freiburg
• (who): Universität
• (when): 2022
• Creator: Rohani, Shahab
• Contributor: Wittwer, Christof ; Koch, Barbara ; Fraunhofer-Institut für Solare Energiesysteme ; Albert-Ludwigs-Universität Freiburg. Fakultät für Umwelt und Natürliche Ressourcen

Further information

• DOI: 10.6094/UNIFR/227145
• URN: urn:nbn:de:bsz:25-freidok-2271453
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 25.03.2025, 1:54 PM CET