America’s largest car manufacturer, General Motors (GM), is preparing to enter the market for stationary fuel-cell power generators, which can be used for fast-charging of electric vehicles (EVs) without installing permanent charge points.

GM expects to start selling a generator based on its Hydrotec fuel-cell technology “within the next year” and sales could reach tens of thousands per year, Joe Mercurio, the company’s fuel-cell business development manager, tells Hydrogen Economist. Sales of GM Class 8 trucks with fuel cells could reach hundreds of thousands, he says.

GM recently announced several non-vehicle commercial applications for its Generation 2 Hydrotec technology, which it developed together with Japanese carmaker Honda. The applications are at different stages, ranging from prototype to near-market. Generation 1 was never sold commercially.

Hydrotec fuel-cell power cubes are also being developed for mobile applications ranging from heavy-duty trucks to aerospace and trains. They have been tested in real-world applications including direct current (DC) fast-charging of multiple EVs such as the GMC Hummer EV and Cadillac Lyriq.

60-600kW – Hydrotec fuel-cell generator output

A mobile power generator (MPG) suitable for EV fast-charging will use GM fuel cells and power integration and management systems developed by fuel-cell solutions provider Renewable Innovations. 

Another model, the Empower rapid charger, is driven by eight GM Hydrotec power cubes and consumes hydrogen from internal tanks. It can fast-charge using DC as many as four vehicles simultaneously, starting at 150kW without expanding the grid. The estimated target full charge time is 20 minutes. More than 100 EVs can potentially be charged before the unit would need to be resupplied with hydrogen, says GM.

This ‘trailerable’ MPG is fully designed and initial development units are being built, scheduled for completion in September 2022. Demonstrations will begin in Michigan and California. A version of the stationary Empower charger built into a 53ft trailer is already providing grid-free EV charging in remote locations. The Empower rapid charger is still under development, and systems will be produced in early 2023.

And a ‘palletised’ MPG could quietly and efficiently power military camps and installations, says GM.

The prototype is the size of a conventional 60kW diesel generator and produces nearly 70pc more power. It also includes battery backup and output regulation, which a diesel generator does not offer. The water emitted can be captured and repurposed in the field, GM says.

Two palletised MPGs were produced in mid-2021 and are supporting EV launches, manufacturing and events. 

Decarbonising generators

Fuel-cell generators could ultimately replace gas- and diesel-fired generators at worksites, buildings, film sets, data centres, outdoor concerts and festivals, says GM, which currently manufactures diesel generators. The fuel-cell units would be about 30pc more efficient than diesel generators, says Mercurio

The fuel-cell generators could also back up or temporarily replace grid-sourced electricity for residential and small commercial enterprises during power cuts.

Each of the Hydrotec-based power generators, which use proton-exchange-membrane technology, feature output ranging from 60-600kW with little heat and noise, notes GM.

30pc – Expected additional efficiency of fuel-cell generators compared to diesel generators

GM’s end goal is for its stationary fuel-cell generators to use green hydrogen, made with solar or wind power, but in the near-term they would more likely use hydrogen made with natural gas, says Mercurio.

Martin Tengler, lead hydrogen analyst at research organisation BloombergNEF, stresses that while such stationary uses for fuel cells are important, they are niche. Over the next 10-20 years, he argues, most hydrogen will likely continue to be used in industry, ammonia and methanol production and oil refining, as well as for uses such as steelmaking. “Is this going to be a game-changing application without which we will not reach net zero? No,” Tengler says.

But he says diesel generators—whether used for backup power for a hospital or data centre or during a California wildfire—do have to be replaced in the bid to get to net zero.

Mercurio notes the flexibility of bringing in stationary fuel cells, which can be used in areas with heavy seasonal traffic such as ski resorts or national parks. The grid does not need to be upgraded if an MPG is used to power EVs. If the use does not pan out, there are no sunk costs from having upgraded the grid, he adds.

Ease of transporting the units is key. The MPG can be transported in a pick-up truck, and the Empower on a larger Class 8 truck.

Demonstration

Multiple development projects involving the MPG are already in progress, including a demonstration of the technology as a mobile charging station for EVs, funded in part by the Michigan Economic Development Corporation and the US Army Combat Capabilities Development Command Ground Vehicle Systems Centre (GVSC). GVSC is also exploring how the palletised MPG can power heavy-duty military equipment and camps.

The MPG EV charging station is set to be demonstrated in mid-2022, says GM.

Multiple development projects involving the MPG are already in progress

The California Energy Commission is funding a separate demonstration programme of four MPGs through its Mobile Renewable Backup Generation Systems initiative to show how hydrogen-based mobile power can help offset the loss of energy during power shutoffs caused by wildfires. This demonstration is being led by the Electric Power Research Institute, an R&D organisation for the electricity sector.

GM will produce Hydrotec fuel-cell systems at its manufacturing joint venture with Honda in Brownstown, Michigan. Renewable Innovations will produce the trailer-based MPG and the larger, modular Empower rapid charger at their facilities in the Salt Lake City metro area.

Renewable Innovations plans to deploy 500 Empower rapid chargers across the US by the end of 2025.

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Author: Ros Davidson