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DoE solar desal program open to produced water treatment tech

The $9 million Solar Desalination Prize is one of several programs supporting the development of treatment technologies that can be used on produced water.

As low-cost freshwater supplies come under increasing threat, the US Department of Energy (DoE) is making efforts to promote the use of nontraditional water resources. One such initiative is the recently launched American-Made Challenge: Solar Desalination Prize, which encourages the development of cost-effective solar-thermal desalination technologies to transform resources such as oilfield produced water, agricultural drainage, industrial wastewater and concentrated brine from inland municipal desalination facilities into reusable potable or non-potable water.

The limitations of standard water treatment technologies make their use on certain wastewater streams challenging and expensive. For example, for pressure-based systems such as reverse osmosis (RO), energy requirements are positively correlated with salt concentration. RO is cost-prohibitive for produced water, which can have salt content three to five times higher than seawater and contains hydrocarbons that foul conventional membranes.

“Thermal desalination technologies are much more tolerant of high salt concentrations because there is a much weaker relationship between salt concentration and energy required,” Becca Jones-Albertus, director of the DoE’s Office of Energy Efficiency and Office of Renewable Energy Solar Energy Technologies, told WiO. “Solar-thermal energy can potentially be a cost-effective option to treat challenging saline water, with minimal electricity and conventional energy resources.”

In addition to the potential cost savings, solar-powered desalination systems could advance water security through deployment at various scales. Small, modular systems could be utilized in remote locations, while industrial-scale systems could provide larger communities with reliable water supplies.

The $9 million four-stage Solar Desalination Prize opened on April 28 and will run through Spring 2022. US-based individuals and groups have until July 16 to enter their submissions. While the earlier stages of the competition are open to solutions of any size throughput, the winning system must be able to produce at least 100 m3/d of freshwater.

“Competitors will submit their innovative concepts for a solar-thermal desalination system, form teams, build their system after having acquired the necessary permitting and approval documents, and demonstrate their system’s operation,” Jones-Albertus said, explaining the competition stages.


Phase 1 is open to all competitors, while subsequent phases will only include teams selected to move forward from the previous round.

Solar Desalination Prize timeline
Source: DoE

Participants can win cash prizes at each stage, amounting to $2.3 million for teams that win all four rounds. An additional $200,000 in vouchers will also be available to redeem at national laboratories as well as qualified partner facilities that are part of the American-Made Network.

“All competitors will be connected with mentoring, training and other services from the American-Made Network,” Jones-Albertus said. “The final winner determined by the DoE will need to develop a commercial and financial relationship for the next steps of technology development, and the network can assist with making those connections.”

The Solar Desalination Prize is one of several recent DoE initiatives that have made funding available for the development of produced water treatment technology. For example, in 2018, the DoE’s Solar Energy Technologies Office provided $800,000 to a partnership between the Lawrence Berkeley National Laboratory and California Resources Corporation for the development of advanced forward osmosis membrane technology to cost-effectively purify high-TDS produced water.

In 2019, the DoE granted a total of $4.6 million to four projects focused on minimizing produced water disposal in favor of treatment and reuse. As with the Solar Desalination Prize, that program was part of the White House-initiated Water Security Grand Challenge.


Descriptive text: The Solar Desalination Prize addresses goals 1 and 5 of the Water Security Grand are expected to be achieved by 2030.

Goal 1Launch desalination technologies that deliver cost-competitive clean water
Goal 2Transform the energy sector’s produced water from a waste to a resource
Goal 3Achieve near-zero water impact for new thermoelectric power plants, and significantly lower freshwater use intensity within the existing fleet
Goal 4Double resource recovery from municipal wastewater
Goal 5Develop small, modular energy-water systems for urban, rural, tribal, national security and disaster response settings

Source: DOE

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