Desalinating inland brackish water requires a reverse osmosis alternative, but a cost-effective renewable evaporative process has been elusive due to high heat input costs.
The Solar Energy Technologies Office (part of US Department of Energy) selected the California-based Sunvapor Company to receive USD1.5 million in funding for its Solar Steam on Demand system. With this solution, the levelized cost of heat for continuously operating distillation equipment will be 1.5¢ per kilowatt-hour, the company says.
Sunvapor describes its solution as using a solar steam architecture that delivers saturated steam pressure at 11 bar as well as thermal energy storage, allowing the distillation equipment to run on solar at night.
“These steam conditions precisely match those needed for most industrial applications such as food processing and refineries,” according to Sunvapor. A prototype solar steam plant will first be deployed for a food processing application, where the tech company sees a need for GHG reductions.
"The production of tomato paste at our scale requires a very significant amount of natural gas to generate hundreds of thousands of pounds of steam per hour in evaporators," said Brandon Clement, General Manager of Los Gatos Tomato Products, LLC. “We believe that Sunvapor’s Solar Steam on Demand has the potential to provide an economically viable reduction to our greenhouse gas emissions,” he said. “By generating steam at night from thermal energy storage we can see a path to exiting Cap and Trade altogether.”
John Larrea, the Director of the Governmental Affairs at the California League of Food Producers, added "Sustainability remains a concern for CLFP members. With their Solar Steam on Demand project, Sunvapor is taking an urgently needed step towards offering a sustainable source of both clean water and energy to our members."
Engineering on the Sunvapor solution is planned to start in the fourth quarter of 2018. Performance testing on the completed prototype plant will take place through the first quarter of 2021, the company says. “The project will serve as a reference for the development of replica solar steam plants with storage throughout California and other states with adequate solar resource.”