American-Made Challenges


Solar Desalination Round 2

Develop systems that use low-cost solar-thermal energy to help clean water produced by oil & gas extraction & other industrial activities.

This challenge is closed

Design Contest open
$1 million grand prize and other awards (TBD)

This challenge is closed


Challenge Overview

Solar Desalination Prize

The Solar Desalination Prize is a competition designed to accelerate the development of systems that use low-cost solar-thermal energy to produce clean water from very-high-salinity water, like water produced from oil and gas extraction. The clean water produced can be used in municipal, agricultural, and industrial applications.



The Opportunity

According to Environment Protection Agency, the oil and gas industry produces several hundred billion gallons of wastewater annually.  This water can have a salt content that is too high for commercially available desalination technologies. Solar thermal desalination can the solution to treating this water, even in remote locations.

The technologies used in solar desalination can also be used in industrial applications like food processing, chemical production, and mineral processing. Solar desalination systems and many industrial applications like food processing do not require high temperatures, so they utilize lower-cost components than other electricity-producing applications.


The Prize Structure

The prize is structured in four phases. Each successive phase is more challenging than the last, with larger prizes and fewer competitors advancing. The challenge requires competitors to make progress on a condensed timeline, form private-sector partnerships, and secure investments to make their ideas a reality. 

By the end of the competition, the teams will have designed their solar-thermal desalination system, obtained the necessary permitting and approval documents, built it, and then demonstrated the operation of their system. The Department of Energy will determine the winner and award a final prize of $1 million in cash. 




Who can participate?

In April of 2020, the Solar Energy Technologies Office at the U.S. Department of Energy (DOE) launched the Solar Desalination Prize competition to help achieve the goals of the Water Security Grand Challenge.

Round 1 is underway in the Design Contest.

Round 2 launched in April of 2021.


Challenge Guidelines

Who can participate?

Entrepreneurs, technologists, hardware developers, engineers, solar experts, and investors are all encouraged to join the challenge, be part of the American-Made Network and create ground-breaking solutions that will accelerate solar desalination technologies.

Please review the official rules for the application process and instructions for competing.


Challenge Updates

Teaming Contest Semifinalists Announced!

April 22, 2022, 11:19 a.m. PDT by NREL Challenge

Congratulations to the Solar Desalination Prize Round 2 semifinalist teams, announced today by the U.S. Department of Energy at the American-Made Earth Celebration. 

  • Sunvapor, from Pasadena, California
  • Planet A Energy, from Pasadena, California
  • SolMem, from Houston, Texas
  • Artic Solar, from Jacksonville, Florida
  • Team Trident, from Santa Barbara, California
  • Winston Cone Optics, from Merced, California

The six semifinalists will receive $250,000 and a $100,000 technical assistance voucher to help design their systems in the Design and Test phases of the competition. 

Learn more about EERE and the American-Made Challenges

Questions and concerns on team collaboration

Nov. 22, 2021, 7:19 a.m. PST by NREL Challenge

We have received a couple of questions surrounded collaborations between competitors within the Teaming Phase of the Prize. As stated in the rules document, the goal for the Teaming Contest is to identify a cross-functional team that can develop and successfully validate an operational prototype of a solar-thermal desalination system. However you build that team is entirely your decision – whether you collaborate with other prize participants, utilize the American-Made Network, or find external experts. The strongest submissions will demonstrate a team that has the necessary experience, expertise, and access to resources required to develop the proposed concept into a prototype. Each entry will be evaluated based on the criteria outlined in the rules.

Recording of Solar Desalination Prize Teaming Event now available

Nov. 10, 2021, 10:31 a.m. PST by NREL Challenge

The recording of the Teaming Event for the Solar Desalination Prize, held Thursday, October 28th, is now available for viewing. If you were not able to make the event, we encourage you to watch each of the 12 Teaming Contest competitors give their 4-minute pitch presentations describing their innovations below. A keynote address by NEOM's Gavin von Tonder is also featured.

Recording of Teaming Kickoff Webinar

Nov. 3, 2021, 2:29 p.m. PDT by NREL Challenge

Hello Teaming Competitors,

We hope you are all making good progress on your Teaming submissions! Below, you will find the link to a recording of the Kickoff webinar on October 18th if you would like to review any of the material covered. We are looking forward to seeing all of your submissions by February 9th.

Good luck!

The Quarterfinalists have been Announced! Next up—the Teaming Contest

Oct. 13, 2021, 12:57 p.m. PDT by NREL Challenge

Register for the Solar Desalination Prize Round 2’s Teaming Event, happening from 12 to 2:30 p.m. ET on Oct. 28 via the virtual conference platform REMO. Meet representatives from the 12 quarterfinalist teams as they present their winning concepts, network with other teams, businesses and individuals looking to support them as they compete for the Teaming Contest.

The Teaming Event will include keynote guest speaker Gavin van Tonder, water sector head of NEOM, and the International Desalination Association.
Register here:  


Frequently Asked Questions

Yes, but it’s quick and easy. Just click the “Accept Challenge” button on this page and follow the instructions to complete your registration. All you need to provide is your name and email address.

If you have a question not answered in the FAQ, we recommend that you post it in the Forum where someone from the prize administration team will respond to you. This way, others who may have the same question will be able to see it.

The specifics of eligibility depend on whether competitors are entering as individuals or as part of a larger entity. Per the Official Rules (also available under the Guidelines section of HeroX): Private entities must be incorporated in and maintain a primary place of business in the United States with majority domestic ownership and control. Academic Intuitions must be based in the United States. An individual prize competitor (who is not competing as a member of a group) must be a United States citizen or a permanent resident. A group of individuals competing as one team may win, provided that the online account holder of the submission is a United States citizen or a permanent resident.
Yes, as long as person submitting is US citizen or permanent resident. Non-U.S. citizens and non-permanent residents may participate if the individuals are legally authorized to work in the United States.
Yes, all team members can sign up on HeroX if they would like to.
Yes, one entity or an individual can prepare up to three submissions for the Innovation phase.
The Team Matching section is a great place to look for potential technology partners with whom to prepare a submission, but you are not required to choose a team member from that site. The Prize Administrator also plans to hold a teaming workshop later in the fall to help winners of the Innovation phase facilitate team matching to complement what is available on HeroX.
Winner of the Innovation phase may be individuals. Any subsequent prize phases must be submitted by an entity (non-profit, for-profit, or academic institution) that is formed in, and maintains a primary place of business in the U.S. with majority domestic ownership and control.
See Section I.6 COMPETITOR ELIGIBILITY of the rules document for eligibility requirements. Teams may choose to reorganize, merge, or disband or merge at any point during the contest as long as they continue to meet the competitor eligibility requirements.
This prize program consists of four contests. To be eligible to win any of the three later contests, applicants must win the previous contest, starting with the Innovation phase. Therefore, contestants who would like to compete for the final Test phase, should apply to the Innovation contest, keeping in mind that each of the four contests within the Solar Desal Prize has its own application requirements and judging criteria. Submissions to each contest will be judged by the stated criteria for that contest. Both new concepts and technologies that are further along in the development process are encouraged to apply.
Yes. However, NREL shall transfer winning funds to only one bank account of the winning team, and shall not be responsible for resolving disputes within teams. Please refer to I.6 COMPETITOR ELIGIBILITY in the rules document. There is no limit on team size.
No, we discourage teams from including any sensitive information in their videos, as they will be made publicly available.
The submission can be an extension of previous Department of Energy or other government funding, but the merits of the ideas described in the contest submission should be made clear rather than saying this is an extension of past work. Each submission will be reviewed based on the information presented in the submission in accordance with the evaluation criteria.
Projects that were funded by other government agencies can be used for this Prize. However, funding cannot be applied from two government agencies for the same efforts.
Competitors may submit applications based on technology they are developing under other government awards and contracts however, they may not use funds from those other awards to compete in this prize program. Specifically competitors may not bill to the other award the following: staff time to develop submissions to this contest, travel to compete in demo days, efforts associated with producing the required video submission for this prize, etc.
There is no age restriction on individuals participating in the Innovation Contest. However, individuals are not eligible to compete in the Teaming, Design and Test Contests.
National laboratories as entities are not eligible to win prizes. Employees of national laboratories are eligible to win a prize as long as the work is not billed to the Federal Government and is done without using federal resources. Federal employees are not eligible to win prizes. Under 15 USC 3719(h) federal facilities may only be used if the federal resources are made available to all individuals and entities participating in the prize competition on an equitable basis.
To be eligible to win, a business entity must be formed in and maintain a primary place of business in the United States and must have a majority domestic ownership and control or must receive a waiver from the majority domestic ownership and control requirement. See section I.6. Competitor Eligibility and Section VI. 17. REQUEST TO WAIVE THE “DOMESTIC OWNERSHIP AND CONTROL” ELIGIBILITY REQUIREMENT in the rules for further information.
While concepts may be relevant to multiple end-use applications, only the technical innovation of the solar thermal desalination process will be evaluated.
The prize is focused on the use of solar thermal energy as a method of desalination, with electricity as a supplement for pumping and other uses. The rules explicitly do not allow solar electricity-driven desalination, but solar can be used as supplementary energy.
While Solar PV may be used to generate electricity as supplementary energy, the primary desalination process utilized must be thermally driven. The rules exclude the use of PV-RO combinations to generate desalinated water. The goals do not explicitly call out a target percentage of energy by thermal and percentage by electricity.
The rules do not exclude active or passive thermal desalination; both are acceptable.
The Innovation contest is open to novel ideas that form the core of a promising solar thermal desalination concept. If you need assistance with other expertise on your team to develop a fully integrated concept, the American Made Network is an available resource to assist with making connections.
The prize rules do not specify continuous or batch operations. The goal is to use solar thermal desalination as a means for desalinated water.
The technical innovation proposed by competitors should be based on a solar thermal desalination process. To develop successful business cases for their technology, competitors may invoke larger systems, using their technology, that also include additional components, which may include electricity generation.
This prize is open to any innovative concept that desalinates water, which is the removal of dissolved salt from an input water stream. Wastewater, produced water, brackish water, and seawater are some examples.
Competitors should consider all costs to produce and deliver water to their target application. An important performance metric for evaluating the innovation is power consumption, which may be significantly affected by how water is transported throughout the system.
The prize is focused on the use of solar thermal energy as the method of desalination, and as such PV+RO is explicitly excluded from the scope of the prize.
The throughput for the pilot scale facility in the Test Contest should be adequate to demonstrate the innovation at meaningful but not necessarily full scale levels. The exact throughput values, however, are highly dependent on the specifics of the innovation.
Yes, all salinities and multiple configurations are welcome. However, it will be incumbent upon the competitor to describe how their design will be cost-competitive for their targeted market(s).
There is not a specific technology readiness level expected for the initial Innovation phase. However, the prize culminates with a pilot test facility build-out, so concepts should be compatible with achieving that level of maturity by the final contest.
If the economic interest and need or market for small systems at price point specified in the prize rules exist, very small systems (< 100 m3/day) may be considered.
The prize rules do not specify an atmospheric pressure level. Competitors should justify that their innovation will be relevant for their targeted application, including consideration of relevant environmental factors.
The prize rules do not specify a solar thermal desalination configuration that is not of interest.

If the lead entity responsible for the submission is majority domestic owned and controlled, no waiver is necessary.  If the foreign teams involvement could be construed as exercising “control” over the team’s efforts then, a team should submit a waiver.