A Win-Win: Boosting Green Hydrogen and Making Wastewater Plants More Efficient with Project SHOW
As the energy transition company, National Grid is accelerating toward its goal of achieving net zero by 2050. This involves not just supporting green energy solutions like wind and solar, but also developing new technologies that can reduce our dependence on fossil fuels. Sometimes, finding ways to increase efficiency and reduce our carbon impact can take us to seemingly unlikely places— such as wastewater treatment plants.
People might not think of wastewater when they think of green energy solutions. But today’s water sector, including the collection and treatment of wastewater, accounts for 4% of global electricity consumption, according to the 2024 World Energy Outlook. In the United States alone, there are approximately 15,000 wastewater treatment plants.
These facilities treat water by adding oxygen to support the breakdown of waste material—either through mechanical aeration with ambient air or by injecting the waste with highly concentrated oxygen created on-site. Introducing pure oxygen allows plants to treat a higher volume of wastewater more efficiently—and in a closed system that takes up less space and reduces the noxious odors that come with open-air wastewater systems. But creating oxygen is expensive, and pumping it into the wastewater is energy intensive.
Nick Rancis, Senior Innovation Manager at National Grid Partners, comes from a background in water treatment technology. And while wastewater treatment isn’t typically part of National Grid’s remit, his experience with the energy challenges of these plants led him to an outside-the-box solution: hydrogen.
“Generating green hydrogen is of great interest to utilities like National Grid as a potential way to decarbonize our gas networks,” said Rancis. “It can be used behind the meter to heat homes and businesses, reducing energy bills. It can power fleets of cars or trucks. And it can be blended with natural gas at varying levels.”
Hydrogen can be produced through a process called electrolysis, which uses electricity to split water into hydrogen and oxygen. Usually, the oxygen produced through electrolysis is simply released into the atmosphere. Rancis’s lightbulb moment? “By placing hydrogen electrolyzers on site at wastewater treatment plants, we can produce hydrogen that lowers the carbon footprint of the energy mix that powers these plants. At the same time, we can use the oxygen that would otherwise go to waste to aerate the wastewater. This has the potential to massively reduce the electrical and carbon footprint of these plants.”
To test this idea, National Grid Partners reached out to Chicago-based startup Celadyne Technologies and researchers at the University of Massachusetts Amherst. Since 2023, the three sides have been collaborating on a pilot project called Project SHOW (Synergistic Hydrogen and Oxygen at Wastewater Facilities), which integrates hydrogen electrolysis with existing wastewater and natural gas infrastructure.
Celadyne, an advanced materials and electrolysis company, has played a key role in refining the solution. Its technology boosts electrolyzer efficiency, making the system viable in areas with high electricity costs, such as the Northeast United States.
“Most of the cost of hydrogen production is from electricity costs, and our technology allows us to reduce that significantly,” said Gary Ong, CEO of Celadyne. “Combining that with existing wastewater and pipeline infrastructure not only makes sense from a practical standpoint, it also reduces costs even further.”
"Not only are closed-system wastewater plants more efficient when they use pure oxygen, but they can now avoid the expense of generating that oxygen before it's pumped into the waste water," Ong added. Project SHOW demonstrates how all these things can work together and reinforce each other.”
Meanwhile, the University of Massachusetts Amherst houses the Water and Energy Technology (WET) Center, a world-renowned research organization that has a pilot-scale testing facility for wastewater treatment technologies. Project SHOW’s bench-scale findings have confirmed that this project is technologically feasible, and National Grid and its collaborators now are seeking a grant from the U.S. Department of Energy to identify wastewater treatment sites that would benefit most from this new technology at full scale.
And the United States could just be the beginning. Looking ahead, this technology could bring benefits to many parts of the world, especially regions where the population is growing swiftly and there’s an urgent need for more energy and better public infrastructure. Combining hydrogen generation with wastewater treatment can help address both needs simultaneously.
“Our goal is to scale this project up with our customers,” said Rancis. “We believe we can save a large amount of electrical energy by reusing the oxygen generated through the electrolysis process. That’s a huge benefit—especially for municipalities that are strapped for cash and struggling to meet decarbonization goals.”
