No Pressure, No Water: How Energy Recovery’s PX Technology Is Rewriting the Rules of Global Water Supply

It’s no longer just a guess that there will be a lack of water. It is a structural reality that is changing infrastructure, investment, and industrial strategy all over the world. Governments and utilities are using desalination and advanced water reuse at an unprecedented rate, from the Middle East to California, Australia to Southern Europe. Energy has long been a limiting factor in the sector, though it has a lot of potential.

Reverse osmosis, which removes salt from seawater and cleans up wastewater, requires a lot of energy, which has made it hard to use and raised costs in the past. But a deceptively simple technology is changing that equation in a big way. Energy Recovery is a company whose PX® Pressure Exchanger® is now used in desalination plants all over the world. The company’s leaders talk about a change that goes beyond small improvements in efficiency. They say that it changes the way we think about the cost of water.

H2O Global News spoke with Rodney Clemente, Senior Vice President of Desalination, and David Kim-Hak, Vice President of Wastewater, about how the technology evolved, where it is scaling next, and why it is becoming central to both seawater desalination and wastewater reuse.

The Energy Problem At the Heart Of Desalination

Desalination has always been constrained by physics. “You can’t mention desalination without mentioning energy,” says Rodney Clemente. “The Achilles heel of desalination has always been the energy-intensive nature of the process.”

Reverse osmosis works by forcing seawater through membranes at extremely high pressure to separate salt and impurities. That pressure requirement translates directly into energy demand, historically making desalination expensive and geographically limited. The breakthrough of the last two decades has been the recovery of wasted energy inside that process.

At the centre of that shift is Energy Recovery’s PX Pressure Exchanger, which captures high-pressure energy from outgoing brine and transfers it directly to incoming seawater. Instead of being lost, pressure is reused inside the system.

“The pressure exchanger has made desalination affordable. It’s made desalination sustainable from an energy intensity perspective,” Clemente explains.

The impact has been transformative. Energy Recovery estimates its technology can reduce energy consumption in the reverse osmosis process by up to 60%, significantly lowering operating costs while improving sustainability metrics at a time of rising electricity prices and tightening carbon regulation.

Wastewater Expansion

For years, desalination was the primary proving ground for the PX technology. But as water stress intensifies, the same physics is increasingly being applied elsewhere. For David Kim-Hak, the next frontier was obvious.

“Having achieved a dominant position in seawater desalination, Energy Recovery began asking a logical next question: where else is reverse osmosis being used, and where else is pressure being wasted?” he says. “The answer was clear, wastewater.”

Advanced wastewater treatment and reuse systems are increasingly reliant on reverse osmosis, particularly in regions pursuing water reuse, indirect potable reuse, and zero liquid discharge strategies. In Kim-Hak’s view, desalination and wastewater are not separate markets, but converging responses to the same global constraint.

“It’s not a binary choice between them,” he says. “It’s becoming an all-in strategy for countries and industries grappling with water scarcity.”

That convergence required technical adaptation. Unlike seawater desalination, where operating pressures are relatively consistent, wastewater applications vary widely. Energy Recovery expanded the PX’s operating range from as low as single-digit bar pressures up to 120 bar, enabling deployment across a far broader set of treatment environments. The underlying principle, however, remains unchanged: direct hydraulic energy transfer with minimal loss.

Efficiency That Changes the Economics

In traditional energy recovery systems such as turbines or centrifugal devices, energy is converted through mechanical stages, introducing losses at each step. The PX takes a different approach: direct pressure exchange between flows. The result is efficiency of up to 99%, a figure that has helped redefine baseline expectations for modern water infrastructure.

Earlier-generation technologies typically operated at far lower efficiencies, particularly outside peak conditions. In contrast, the PX is designed for consistent performance across its operational life, with minimal degradation over time.

Built from advanced ceramic materials and engineered for long service life, the system also requires no scheduled maintenance, a factor that significantly alters lifecycle cost calculations.

For utilities, however, efficiency alone is no longer the deciding factor. Market conditions are now playing an equally important role.

Why Energy Price Volatility Changed Everything

For much of the past decade, incremental efficiency gains were often difficult to justify in wastewater treatment. Energy savings of 20–30% were valuable, but not always decisive.

That has changed.

“Every penny counts now,” says Kim-Hak. “Adding a PX is one of the most effective ways an operator can de-risk their exposure to rising energy costs.”

He points to California, where electricity prices for wastewater operators have risen from roughly eight cents per kilowatt hour a decade ago to around 14 cents today, with volatility expected to continue. The implications extend beyond cost. Lower energy consumption also translates directly into reduced carbon emissions, giving operators a measurable sustainability benefit that increasingly matters to regulators, investors, and communities. In this environment, efficiency shifts from optional upgrade to operational necessity.

Scaling Up: The PX Q650 And the Mega-Plant Era

As desalination projects increase in size, so too must the technologies supporting them.

Modern plants are no longer measured in tens of thousands of cubic metres per day, but in hundreds of thousands, with some approaching or exceeding one million cubic metres per day.

To meet that scale, Energy Recovery developed its latest generation device: the PX Q650.

Compared with its predecessor, the Q400, the Q650 delivers a 63% increase in peak flow capacity, alongside lower mixing, reduced frictional losses, and improved system efficiency. In practical terms, fewer units are required per plant, reducing footprint, simplifying design, and improving operational flexibility.

“If you had a desalination plant, would you rather put 1,000 pressure exchangers in your plant or 100?” Clemente says. “You probably want the fewer number that gets you the flexibility, availability and savings you need.”

The design reflects a broader shift in desalination infrastructure: fewer, more efficient system components optimised for scale.

Reliability As An Economic Factor

In large-scale water infrastructure, performance is only part of the equation. Availability can be just as critical.

“The most expensive water in the world is the water you can’t produce or sell,” Clemente says.

Unplanned downtime or maintenance interruptions can translate into substantial financial losses over the lifespan of a plant. For operators working under long-term supply contracts, reliability is not optional.

The PX is engineered to address this directly. With a single moving component and a process-water lubricated design, it avoids many of the mechanical failure points found in conventional systems. Its materials are selected for corrosion resistance and long-term stability in harsh operating environments. Clemente emphasises that the technology delivers the lowest lifecycle cost when energy, maintenance, and downtime are considered together.

From Static Systems To Intelligent Water Infrastructure

Beyond hardware, both executives see a broader shift underway in how water systems are operated. Traditionally, desalination and treatment plants were run as static systems: once optimised, they were left largely unchanged. That model is beginning to evolve.

“In the past, once operators achieved the water quality and flow they needed, they would set their valves and pumps and leave them,” Clemente says. “The future is different.”

Operators are increasingly looking to optimise plants dynamically, adjusting output based on energy pricing, temperature conditions, and demand fluctuations. This shift aligns water infrastructure more closely with digital systems already transforming other industries.

“The future of water treatment is optimisation,” Clemente says. “And optimisation is going to be directly related to the digital world.”

Kim-Hak sees this as the early stages of a broader transformation, where efficiency technologies like the PX become integrated into real-time operational strategies rather than functioning as standalone components.

A Technology Becoming Essential Infrastructure

As water becomes scarcer, desalination and reuse are becoming more than just extra options; they are becoming essential parts of infrastructure. For Energy Recovery, that change has made energy efficiency a system requirement instead of just a way to improve performance.

“Every single desalination plant that you build today must have an energy recovery device in it for it to work technically, economically, and to be feasible,” Clemente says.

It is a strong claim, but one increasingly reflected in market behaviour. As plants scale, energy prices fluctuate, and sustainability targets tighten, wasted pressure becomes an inefficiency the industry can no longer afford.

Kim-Hak believes the trajectory is already clear: desalination and wastewater reuse are converging, and the pressure exchanger will sit at the centre of both.

In his view, wastewater is now where desalination was two decades ago: early in its expansion curve, but rapidly accelerating.

That convergence points to a broader conclusion shared by both executives. Water infrastructure is entering a new phase, one defined not only by production capacity, but by how efficiently every unit of energy is used.

For Energy Recovery, the opportunity is to sit at the centre of that shift. One device. Two industries. And a global system learning, under pressure, to waste less.

You can meet with Energy Recovery experts later this month at the European Desalination Society conference, June 23rd–25th, Booth B9 or at Singapore International Water Week, June 15th–18th, in Booth B2 G19.