The most expensive part of a solar-powered desalination plant is often the battery. The power is free, but storing it for when the sun isn't shining is not. Modulus Water, a new Atlanta-based startup, is betting it can cut that cost to zero by skipping the battery entirely. Its systems run on solar power and store water, not electrons, in a shipping container that can be dropped anywhere in weeks [moduluswater.com, retrieved 2024].
A PhD in Batch Reverse Osmosis
The company is the brainchild of Jonathan Burbaum, who holds a PhD from MIT's Lienhard Research Group, where he specialized in batch reverse osmosis [moduluswater.com/team, retrieved 2024]. Burbaum previously founded Harmony Desalting, which won a $150,000 grand prize from the U.S. Bureau of Reclamation and secured roughly $1.5 million in non-dilutive funding [moduluswater.com/team, retrieved 2024]. He has also spent the last few years writing a Substack series called 'Healing Earth with Technology,' which concluded in July 2025, just as Modulus Water was founded [healingearthwithtech.com/about, retrieved 2026].
The Containerized Wedge
Modulus's core bet is that for many potential customers, the grid is either unreliable, expensive, or simply non-existent. Its target is the intersection of water scarcity and grid constraints, serving communities, farms, and industrial users who need reliable water without a reliable power connection [moduluswater.com, retrieved 2024]. The product is a modular, containerized system designed for rapid deployment. The company claims its AI controllers can predict solar availability and dynamically optimize production schedules [moduluswater.com, retrieved 2024].
| Competitor | Core Technology | Primary Energy Source | Key Differentiator |
|---|---|---|---|
| Modulus Water | Batch reverse osmosis | Solar PV | Containerized, rapid deployment; stores water, minimal battery use. |
| Oneka Technologies | Wave-powered desalination | Ocean waves | Floating, zero-grid, zero-emission units anchored offshore [bbc.com, retrieved 2026]. |
| Elemental Water Makers | Reverse osmosis | Solar PV | Focus on energy recovery and system optimization for existing RO plants [elementalwatermakers.com, retrieved 2026]. |
| Desolenator | Thermal desalination | Solar thermal | Uses waste heat for pre-treatment, aims for zero liquid discharge. |
The Venture Climate Alliance Bet
In 2025, Modulus Water raised a $1.5 million seed round [retrieved 2026]. The lead investor was not disclosed, but the round included participation from the Venture Climate Alliance, a consortium of venture firms focused on funding climate solutions.
Where the Physics Gets Hard
The concept is elegant, but the path to commercial scale is paved with hard engineering and unit economics. The company is entering a field with established players, each with a different wedge into the problem.
- The reliability question. Solar power is intermittent. Storing water is cheaper than storing electrons, but it requires a large enough reservoir to tide over multiple cloudy days while still meeting customer demand.
- The cost-per-liter race. Desalination is an energy-intensive process. The efficiency of Modulus's batch reverse osmosis process versus conventional systems will directly determine the size and cost of the required solar array.
- The deployment reality. While 'deploys in weeks' is a compelling marketing line, the real-world hurdles of site preparation, permitting, and local water rights are often the slowest part of any infrastructure project.
The Next Twelve Months
With its seed capital, Modulus Water's immediate task is moving from validated research to a field-tested product. The next milestones are straightforward: a working prototype, a named pilot customer, and published performance data. The company isn't trying to beat the massive, grid-tied desalination plants of the Middle East. Its target is the smaller, distributed incumbent: the diesel generator humming next to a standard reverse osmosis unit, burning fuel to make water.