Exploring Hydrogen Production at Water Resource Recovery Facilities

Production and use of low or zero emission hydrogen will be an integral part of the energy transition. As water utilities seek to decarbonize, and governments around the world announce billions of dollars in clean hydrogen funding, there is growing interest in the synergies between hydrogen (H2) production and water (H2O) resource recovery facilities (WRRFs).

Integrating hydrogen production with a WRRF is attractive because it can reduce overall operations and maintenance costs for both the hydrogen production and wastewater treatment processes. Synergies include the use of treated wastewater as feed or cooling water for the electrolysis process that produces hydrogen; using biogas produced by the WRRF to produce hydrogen via pyrolysis; and replacing or augmenting the existing WRRF’s oxygen supply with the by-product of electrolysis. 

Despite the numerous synergies, however, the true value of hydrogen production at WRRFs is not universal.  

For example, it is critical to understand the market conditions for hydrogen. Much like renewable natural gas generated from biogas at WRRFs, hydrogen is a product that can be used to supply municipally owned vehicle fleets and power plants – or can be sold in the market for applications such as transportation and other industrial uses. If a utility plans to sell the hydrogen, they should account for the surrounding market such as potential offtakers, availability of infrastructure to receive and convey the hydrogen and its projected sale price. 

There may also be circumstances where hydrogen production is not the best use of a utility’s water, power or space. In areas facing water scarcity, treated wastewater may be prioritized for potable or non-potable reuse to mitigate water shortages. It may be politically challenging to use a portion of that water to develop and sell a product primarily for economic gain. Likewise, a WRRF could use biogas for onsite heat and power to run the plant, use it for vehicle fueling or sell it as renewable natural gas. These options are more established, have a ready market and are most likely more economically valuable in the short-term.

While the hydrogen economy remains in its infancy, there currently are simpler, more feasible methods to capitalize on the water and power recovered at a WRRF. However, several changes on the horizon may incentivize hydrogen production:

• Increasing restrictions on carbon emissions, even those from biogas. This could push conversion of biogas to hydrogen, which would result in lower emission power generation.
• As WRRFs become net energy positive via increasing efficiency and power generation, the extra energy must be stored or utilized, and the electrical grid or batteries may not be the optimal methods. Hydrogen can be an excellent, and marketable energy storage medium.
• The evolution of the hydrogen economy should increase the demand for hydrogen and decrease the cost of production via cheaper materials and production credits.

Due to the clear synergies between hydrogen production and wastewater treatment, we can expect WRRFs to play a role in the production of clean hydrogen and the global energy transition. Water utilities should nevertheless understand the complexities and trade-offs – particularly in the short term as the hydrogen economy develops. 

I’ll be sharing more details on the synergies, pitfalls and opportunities of hydrogen production at WRRFs during a technical presentation at WEFTEC 2024 in New Orleans, October 5 – 9.