Truck Trends: How do hydrogen fuel cells work?

Much of the spotlight around zero-emission vehicles focuses on battery electric equipment. Hydrogen-powered fuel cells continue to show promise for those who need to travel longer distances between stops. Think of a Class 8 truck that can travel closer to 800 kilometers when fully fueled.

But how do they work? Who are the players? What are some of the operational considerations? We’re about to explore these issues and more. I’m John G. Smith of, and this is Truck Trends.

Fuel cell electric trucks are still limited to prototypes, but some familiar nameplates are involved in the engineering. Daimler and Volvo, competitors by every other measure, joined forces to commercialize the underlying tech in a venture known as cellcentric. Paccar is bringing its trucks to market with Toyota fuel cells. And then there’s Nikola Corporation, which has brought a fuel cell electric truck to market — recently testing it in Alberta.

By many measures, these are electric vehicles, but the difference is that the fuel cell electric vehicles produce electricity on board.

How does a fuel cell work?

The magic happens in the fuel cells — a stacked series of anode plates and cathode plates divided by electrolyte membranes. Now hydrogen drawn from the truck’s tanks enters the anode side, contacts the membrane, and splits into hydrogen ions and electrons. But only the hydrogen ions pass through the membrane. The electrons left behind are forced to follow an electric circuit, and this generates the all-important electric current that drives motors, turns wheels, and helps replenish an onboard battery when the truck needs a little extra power.

When the hydrogen ions and electrons finally combine with some atmospheric oxygen on the cathode side of this engineered sandwich, it all forms nothing more than water and a bit of heat. No tailpipe emissions at all.

That’s the chemistry and the engineering behind it. But let’s look at the practical matters. The choice between a battery electric truck and a fuel cell electric truck is largely dictated by packaging and weight.

One of the benefits to a fuel cell electric truck is that hydrogen boasts a higher energy density than batteries at equal weight. A battery electric truck would need to stop to recharge before a fuel cell electric truck would have to refuel. Not only that, but work with pre-production models suggests the hydrogen supplies can be replenished in about 15 minutes — and that’s far less than a battery electric charging time.

All this said the choice of fuel is going to play a big role in just how green these vehicles can be. More after this.

I sat down with Volvo Trucks product manager Daniel Bergstrand to discuss the technology.

Daniel Bergstrand discusses fuel cells

Daniel Bergstrand: You can look at the fuel cell electric vehicle trucks, they are suitable for long haul and when there is limited access or time for charging and refueling that will occur at the dispensing station and to start with at least it will be gaseous hydrogen, which is compressed and filled into the hydrogen tanks of the vehicle. And this process of filling that potentially can give up to 1,000 kilometers range that will be conducted in less than 15 minutes.

Green hydrogen produced from electrolysis powered by renewable electricity from solar, wind, hydro, that is the best and most sustainable way to produce hydrogen. So we will likely see a tremendous growth of green hydrogen supply in the years to come.

And mainly we think that is because large industries, they will use hydrogen to reduce their climate impact.

Still, it might be so that demand will exceed supply during a transitional period. And then other colors of hydrogen can also support decarbonization. So we have, for example, blue hydrogen — and that is produced from natural gas with CO2 separated and stored with the help of carbon capture technology and that has the potential to reduce climate impact until green hydrogen is widely available. It’s also possible to produce hydrogen from renewable natural gas.

Then we have a pink hydrogen that is produced through electrolysis powered by electricity from nuclear energy. And that also has some good decarbonization potential, and so do the colors of hydrogen as well. However, grey, black and brown hydrogen that is produced out of the fossil sources and without capturing CO2, this is not supporting decarbonization.

There will be a standard to fulfill hydrogen for fuel cell electric vehicles. And as long as you fulfill that standard, it will not be a difference in how the vehicle behave. Depending on the color of hydrogen, how it’s produced.

Questions remain

John G. Smith: Environmental considerations don’t end there. Some critics of the fuel point to the energy lost when using electrolysis – the process of using an electric current to separate the hydrogen and oxygen and water, compressing it, storing it, and running it through a fuel cell. There’s still plenty of questions to address. But when environmental concerns combine with the need to travel longer distances, fuel cells may be part of the answer.