There are no quick fixes to long-term energy challenges. To find solutions, governments and industry benefit from sharing resources and accelerating results. For this reason the IEA enables independent groups of experts - the Energy Technology Initiatives, or ETIs1.
Concentrated solar power (CSP) technologies use large, sun-tracking mirrors to concentrate sunlight. Combined with high-temperature thermal storage for backup supply, CSP plants can provide flexible, baseload electricity production as well as produce high-temperature heat for industrial processes or to purify or desalinate water. Despite the higher investment cost, CSP plants use many available technologies such as steam turbines, and electricity from CSP can be produced at a competitive cost per kilowatt-hour. Policies and measures to capitalise on this potential include long-term funding for additional research, development and demonstration (RD&D), financial incentives, proper planning and environmental assessments, and streamlining the permitting process for new plants.
The aim of the ETI focusing on concentrating solar (SolarPACES) is to facilitate technology development, market deployment and energy partnerships for sustainable, reliable, efficient and cost-competitive concentrating solar technologies by providing leadership as the international network of independent experts. There are 19 Contracting Parties (including Algeria, Brazil, China, Egypt, Israel, Mexico, Morocco, South Africa, and the United Arab Emirates) and one Sponsor.
Many countries and regions with the most hours of annual sunlight also have a shortage of fresh water resources. For this reason, the SolarPACES project “Solar Energy and Water Process and Applications” aims to combine the benefit of high-temperature steam and electricity from CSP plants to purify waste or standing water and drive processes to desalinate seawater. Despite recent advances in energy efficiency, desalination plants are energy intensive and often operate using fossil fuels. Using exhaust steam from CSP plants would not only improve overall efficiencies but would also significantly reduce greenhouse gas emissions.
For these reasons, the SolarPACES subtask, Concentrated Solar Power and Desalination Plants, set out to examine cases of CSP plants combined with desalination in arid countries. Participants examined CSP-desalination demonstration projects in Egypt, Jordan, Israel and Spain. Detailed comparisons of systems configurations, components, materials and operating regimes were made. Salt concentrations and the location of the plant were also considered.
Two cases were examined in the Mediterranean region, the first focussing on a combined CSP‑desalination plant (using reverse osmosis) located on the shore, and a second focused on a CSP plant located inland, transmitting electricity to a coastal desalination plant (multi-effect distillation). Much of the coastal land is occupied and the amount of annual sun is somewhat lower due to cloud cover. However, it was found possible to generate 10.4 gigawatts (GW) of power and to desalinate 8.3 million cubic metres per day of water on the combined coastlines of Egypt, the Red Sea and the Persian Gulf.
The second case examined CSP plants located further inland, where electricity was transmitted to the coastal desalination plant. This configuration was not always possible due to the state of the electricity grid, and where it was possible, it resulted in transmission losses between the CSP installation and the desalination plant. However, the net result was found to be beneficial, as the multi-effect distillation process of desalination was found to be thermodynamically more efficient, requiring a smaller solar CSP plant to produce the same amount of electricity.
* Photo courtesy of CIEMAT.
For more information: www.solarpaces.org
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