Electric vehicles are getting the lion's share of the zero-emissions attention, but hydrogen has long been lurking along the sidelines. Toyota, Hyundai, General Motors, Honda, and more have all been pushing the use of the gas to produce electricity on board the car. Allowing zero-emissions driving with no waiting for recharging. Though it's been around for decades, it's still new to most, and still confusing. Here's everything you need to know about hydrogen for power as well as the fuel-cell electric vehicle.
How fuel cells work
We'll start with how fuel cells work, or at least the simplified version of it. The fuel cell stack is where the magic happens, and the conversion of hydrogen into electricity (and water) largely is magic. Hydrogen gas is pumped into the anode of each fuel cell (it will have hundreds of these cells in each system, referred to as a fuel cell stack). The hydrogen reacts with a catalyst and releases its protons and electrons. The protons pass through a porous membrane while the electrons run through a circuit and create an electric current. At the cathode, the protons and electrons combine with oxygen from the air to produce water. It's silent, efficient and leaves only electricity, water vapour and some heat as waste.
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General Motors Fuel Cell Controls and Process Engineer Joe Truchan operates a coating machine in the fuel cell laboratory at the GM Global Propulsion Systems Pontiac Engineering Center in Pontiac, Michigan. (Photo by Steve Fecht for General Motors)[/caption]
Quick fill ups
Still more than you wanted to know? That's fine, how it works isn't important. What is is that you pump in hydrogen gas and you get electricity and water vapour on the other side. Enough electricity to power a car.
Because that power can't go straight to the motor (usually), a small EV battery is fitted to store and buffer the electricity. Hydrogen gas is stored in tanks. Toyota's Mirai, one of the few FCEV vehicles on sale now, has two storage tanks that weigh almost 90 kg, store the gas at 10,000 psi, and hold about five kg of hydrogen.
The five kg doesn't sound like much. It's about the same weight as five litres of gasoline, but remember the gas is compressed. The tanks hold 122 litres of hydrogen gas total, enough to give the sedan an estimated 502 km of range. Like an EV, thanks to its small batteries, a FCEV can also recapture energy from coasting and braking, helping to add range and efficiency.
Even more importantly, filling up a hydrogen fuel cell vehicle's tank happens in just a few minutes and at a normal-looking pump. While the station needs to have a supply of hydrogen in a pressurised tank, they aren't required to build and install large amounts of electrical infrastructure to support multiple vehicles charging at Level 3 rates, which also means there is no taxing of local electrical grids. Even if hydrogen gas is produced on-site, the electric load is balanced throughout the day, not used in short high-draw bursts.
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General Motors' Hydrotec fuel cell power cubes contain more than 300 fuel cells along with thermal and power management systems. (Photo by Steve Fecht for General Motors)[/caption]
Where does it come from?
Hydrogen, at least for current needs, is made using natural gas reforming. It is a process where natural gas and high-temperature steam are combined, the result is hydrogen, carbon monoxide, and carbon dioxide. Most of the CO can be turned into more Hydrogen, but CO2 is still an end product. Still, the U.S. Department of Energy says this cuts greenhouse gas emissions 90 percent compared with gasoline.
We can also make hydrogen using electrolysis. Adding electricity to water with a process in the middle that splits the water into hydrogen and oxygen. With green energy, like hydroelectric, solar, or wind, this can produce hydrogen gas with zero emissions, making FCEVs emissions-free. Both methods are still expensive, though efforts are underway to reduce the costs to $2/kg and eventually $1/kg. Today's costs are closer to $20/kg, though some of the on-sale vehicles include the cost of fuel, essentially making it free for the person who is driving the car.
Where can you fill up?
In Canada, there are currently five hydrogen filling stations. One in Quebec City, one in Victoria, and three in Vancouver, meaning that if you want to make a coast to coast trip, you're out of luck.
Work is underway, though, to add more hydrogen refuelling infrastructure. Just last June, Natural Resources Minister Seamus O'Regan announced a $2.3 million investment into the Alberta Zero-Emissions Truck Electrification Collaboration, working to address barriers to fuel cell big rig adoption with more sources in that province. More B.C. locations are planned by the Hydrogen Technology & Energy Corporation. HTEC is also planning six more stations in Quebec, which has both a large quantity of affordable green power and a government encouraging zero-emissions vehicles and transportation solutions.
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The Chevrolet Colorado ZH2 fuel cell electric truck loves the mud and its 37” tires and extreme approach and departure angles show its capability on the Heavy Vehicle Test Area at General Motors’ Milford Proving Ground. The hydrogen-powered fuel cell in the ZH2 runs nearly silent, can export up to 25 kW of electric power and generate up to two gallons of useable water per hour from its only emission, which is water vapor.[/caption]
What cars are on sale today that use a hydrogen fuel cell?
Toyota currently offers the Mirai fuel cell sedan in the U.S. and Canada. Here, the second-generation sedan is set to be sold exclusively in B.C. and Que., though it appears that sales launch has been delayed. The first-generation vehicle saw more than 50 sold in Canada. Honda offered the Clarity FCEV in one U.S. state, but the model did not go on sale in Canada. Hyundai does offer the NEXO fuel cell crossover in Canada. The brand just recently added the 2021 version to its website, with pricing from $73,000, offering a five-minute refuel time and 570 km range.
If you want to experience a hydrogen car, you'll need to live in or around Vancouver. Earlier this year, Lyft and Toyota, through its Kinto Share service, made a number of Mirai FCEVs available to rent to drivers who use the Lyft platform there. Meaning they can rent them (for as little as $198/week), and you may be able to hire one for a ride.
Trucking industry will benefit
Long-distance trucking may be the ideal place for hydrogen fuel cells. While electric big rigs like the planned Tesla Semi offer ranges longer than any car, they also require massive charging infrastructure, hours to charge, and, more importantly, several tonnes of batteries. A big rig running on zero-emissions hydrogen could fill up in minutes and travel coast to coast in the same amount of time as a diesel truck. It would also be able to haul similar payloads since the truck's FCEV driveline would not require large battery capacity cutting into allowable weight.
Toyota is currently testing FCEV trucks around the Port of Long Beach, in California. Kenworth, Daimler, Cummins, and General Motors are all currently either in development of cells or are testing them on the road.
Still a few challenges, but the future is bright
For now, the challenges are similar to those faced by EVs. The tech is expensive, and the infrastructure doesn't exist. Unlike EVs, though, once those two challenges are met, there are not large ongoing issues with mining for materials like lithium and cobalt. Fuel cells also solve the issues faced by major transportation firms including range and filling time, making them practical for trucks, trains, and ships.
While hydrogen fuel cells haven't had the glitz and glamour of the EV, the technology has been in research for nearly as long, showing impressive results. With just a few hurdles to cross, it could be ready for the highway sooner than you might expect.