US Startup Pitches Green Hydrogen For Off-Grid EV Charging

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The green hydrogen market has been a tough nut to crack, and it got a lot tougher here in the US after federal energy policy took a sharp U-turn last year. Still, the technology continues to evolve as a replacement for the traditional hydrogen supply chain, which consists of natural gas and coal. In addition, innovators are spotting new demand opportunities, enabling them to fill energy gaps that other power-producing resources have left open.

The Green Hydrogen Alternative

The California-based green hydrogen startup HyWatts is one example, having surfaced on the CleanTechnica radar last week in connection with  a new EV charging plan that focuses on charging station reliability in off-grid sites and other diverse locations.

HyWatts is also aiming at the booming data center space. In the meantime, deploying green hydrogen systems for off-grid battery-powered EV charging is an area of focus. The idea was put into practice by the Extreme E branch of the Formula E EV racing organization several years ago. Another example comes from Texas A&M University, which is participating in a green hydrogen EV charging station study with partners in Qatar.

For those of you new to the topic, green hydrogen is pushed from water in electrolysis systems, with the electricity ideally supplied by wind, solar, or other renewables (see more green H2 background here). As for why hydrogen is needed in the first place, that’s a good question. Green or not, hydrogen plays a ubiquitous role in industrialized economies. It is an input for ammonia fertilizer among many other chemical products, and it can be combusted as a fuel or converted into electricity in a fuel cell.

Some electrolysis systems are grid-connected and use electricity from whatever resource is available, which may include a measure of fossil fuels or nuclear energy. HyWatts, though, is among the stakeholders focusing on opportunities to deploy renewable energy.

Cutting The Cost Of Green Hydrogen

There being no such thing as a free lunch, electrolysis systems are expensive. Ratcheting costs down has been a significant hurdle in the way of commercial application. HyWatts has identified an opportunity in the off-grid space, where cost can be balanced against availability and reliability.

The company describes its new, proprietary “Power-Plant-in-a-Box” as a turnkey, transportable system that can be used directly for power generation when the sun is out while converting excess solar energy to hydrogen, and storing it for later use. In that context, hydrogen acts as a battery that can outlast outlast conventional lithium-ion energy storage technology by a wide margin

The company’s “Reversible Fuel Cell” is a single, integrated PEM (proton exchange membrane) system that generates electricity in one mode, and produces hydrogen in another. The integration of the two functions arises from the use of a high-temperature membrane operating in the range of 160°C, in which water and other reactants are in a gaseous state. “This provides an opportunity to combine the functionality of the electrolyzer and the fuel cell into a single unit, the Reversible Fuel Cell,” HyWatts summarizes.

The company explained its position in a white paper published last year:

“Since the fuel cell and electrolyzer are the most expensive subsystems of hydrogen-based energy conversion solutions, we have chosen a three-pronged strategy to reduce their cost: 1) simplification of the BoP, by eliminating or simplifying costly components such as water treatment and cooling. 2) optimizing the overall system efficiency and performance. 3) combining the fuel cell and electrolyzer in one device (Reversible Fuel Cell), eliminating a significant cost driver.”

BoP refers to balance of power, meaning all of the components of a system that support the key elements. By combining two processes in an integrated unit, HyWatts reduces BoP related to valves, heat exchangers, water treatment, control systems, and other supporting equipment.

Traditional PEM systems are designed to operate at 60°C to 80°C, which saves on energy costs but requires meticulous control of impurities. High temperature systems generally operate in the range of 150°C to 200°C, with HyWatts citing 120°C to 180°C as the temperature range. The comany lists several key advantages of high temperature systems:

Air cooling can be used instead of a complex liquid cooling system.

Membrane humidification systems are not necessary with the HT PEM membrane.

Water for the electrolyzer is fed to the stack as steam, which by nature is demineralized and consequently does not need expensive pre-treatment.

HyWatts also notes that the system produces heat at temperatures exceeding 150°C on the electrolyzer side, which is recycled as pressurized steam and re-applied to the electrolyzer, resulting in improved efficiency.

What About The Membrane?

The expense, efficiency, and durability of membranes is one of the key factors keeping the cost of electrolysis stubbornly high. HyWatts’s contribution to the field is a membrane tweaked with phosphoric acid. The company contrasts its technology with conventional PFSA (perfluorosulfonic acid) memberanes, which require constant moisturization.

“This allows us to remove the humidification and reactant recirculation systems required for LTPEM systems. It also increases the operational temperature range from 60-80°C for LTPEM to 120-180°C for HTPEM,” Hywatt states, referring to the difference between low-temperature and high-temperature PEM.

HyWatts also takes note of a key obstacle to its high-temperature membrane. “Highly concentrated steam can wash out phosphoric acid when it passes over the membrane surface, resulting in rapidly reduced proton conductivity of the membrane and contamination of the catalyst in the electrode,” the company explains. However, Hywatts states that it has identified new materials that can protect the membrane from acid loss.

Next Steps For Green Hydrogen In The USA

If you are familiar with phosphoric acid-doped electrolyzer membranes, share your thoughts in the discussion thread. Meanwhile, other signs of green hydrogen activity have been bubbling up stateside. Although some large-scale projects were canceled or delayed after US President Donald Trump disrupted the short-lived Regional Clean Hydrogen Hubs program, HyWatts is not the only innovator eyeballing cracks in the fossil fuel facade.

Another startup to surface on the pages of CleanTechnica is Texas-based Talus Ag, which has developed an integrated green hydrogen system that produces green ammonia fertilizer. Talus Ag initially trialed the system in combination with solar power at a site in Iowa, demonstrating how farmers can access locally produced fertilizer instead of depending on global commodities markets.

In March, Talus Ag announced that it is pitching the system in Minnesota, where it aims to recruit wind energy stakeholders. The plan is to use excess wind energy from turbines that would otherwise be curtailed due to low demand, thereby increasing revenue for the turbine owner while providing local farmers with a secure, reliable source of fertilizer.

Uptake in the US being slow, green hydrogen innovators in the US are seeking greener pastures elsewhere around the globe, including the New York startup Plug Power and Massachusetts-based Electric Hydrogen. Talus Ag is another example. In May, Talus Ag nailed down an agreement with PepsiCo covering Europe, Sub Saharan Africa, and Asia Pacific among other regions. “Decarbonizing fertilizer is important to advancing climate progress at scale, but it should be done in a way that works for farmers,” explained PepsiCo VP of Sustainable and Regenerative Agriculture Margaret Henry in a press statement.

Henry also mentioned something about the “long-term transition of the fertilizer market,” so hold on to your hats…

Image: The California-based green hydrogen startup HyWatts is pitching a modular, transportable “Power Plant In A Box” combination electrolyzer system and fuel cell for off-grid EV charging, among other purposes (cropped, courtesy of HyWatts).