Pros and Cons of Hydrogen Cars

Business, Technology  /   /  By Bradley Berman

When it comes to energy, driving and many other things in life, there’s no free lunch. That’s true for the energy needed to power your daily ride, regardless of whether the source is petroleum, biofuels, electrons in a battery, or hydrogen fuel cell cars. So the decision about buying or leasing a fuel cell car—like every other powertrain and fuel option out there—is a matter of trade-offs. Here’s a quick rundown of the pros and cons of an H2 car.

PROS

Long Driving Range
With a full tank of hydrogen gas, you can travel nearly 300 miles. That amount of range matches most gasoline-powered cars, and handily beats battery-electric cars. Unlike a battery-electric car that stores energy in a battery, which is then run directly through an electric motor, a hydrogen car carries energy as a gaseous fuel in a high-pressure tank—and then it’s put through a fuel cell. With a fuel cell, nothing is burned. There are no combustion losses or wasted heat. Because of the added efficiency, a kilogram, or 2.2 pounds, provides about twice the driving range as a gallon of gasoline—even though it contains about same amount of energy as that gallon. Pump in about four or five kilograms of hydrogen, and there’s enough energy there for hundreds of miles of range.

Quick Refueling
Hundreds of miles of driving range is great, but the key to the usefulness of a hydrogen car is that a full tank of H2 can be replenished in about five minutes. The process is remarkably similar to pumping gasoline. You roll up to a dispenser, swipe a credit card, place the nozzle in the fuel inlet, and let the fuel flow. As opposed to gasoline or diesel, which are liquid fuels, the line has to be sealed and pressurized to allow hydrogen (as a gaseous fuel) to go into one or more tanks in the car. In the case of both gasoline and hydrogen, the transfer of the liquid or gaseous fuel is completed in a matter of a few minutes. This is a distinct advantage to battery-electric cars that can take hours to recharge. Even so-called “quick charging” of a battery-electric car can take as long as 30 minutes to replenish a depleted battery pack—and big packs offering more driving range take longer to recharge.

Only Emissions Are Water Vapor
Hydrogen cars have a tailpipe, but the only thing that comes out is water vapor. You could take this fact at face value follow (and move on to the next point), or try to wrap your mind around the chemical process that allows propulsion to happen without noxious emissions. In essence, the fuel cell transforms a chemical form of energy (hydrogen and oxygen) into electrical energy. Hydrogen gas stored in a tank travels through the fuel cell’s channel (or plates) until it hits a membrane covered with a platinum catalyst. It then splits apart into protons and electrons. The protons pass through, but due to the properties of the catalyst, the electrons can’t advance from the hydrogen side (the anode) to another plate on the other side containing oxygen (the cathode). So an electrical path is provided for them, handily routing them as electrical current to a motor. Meanwhile, on the cathode side, protons and electrons are reunited and, together with the oxygen, form water. That’s what comes out of the tailpipe, and nothing else.

Can Be Made by Renewable Sources
As we have explained on this site, hydrogen is not in and of itself a fuel. Instead, it’s best seen as an “energy carrier,” and has to be extracted from something else. The most common method is steam methane reforming from natural gas, obviously a non-renewable fossil fuel. But hydrogen can also be produced through electrolysis—the process of passing an electric current though water to separate water (H2O) into oxygen (O2) and hydrogen gas (H2). If the electric current comes from a renewable source, like solar energy, then you are essentially converting energy from sunlight into hydrogen energy. The Department of Energy’s National Renewable Energy Laboratory also lists these promising methods for deriving hydrogen from renewable sources: biological water splitting (using sunlight and microorganisms); pyrolysis or gasification of biomass resources; and solar thermal water splitting.

Quiet Electric Drive
Regardless of how the hydrogen is produced, the driving experience is virtually identical to driving a battery-electric car: in other words, it’s very quiet. There are unfamiliar hissing and compressor noises that don’t always get louder and quieter with pressing and releasing the accelerator. But compared to the firing of cylinders in an internal combustion engine, the movement of gaseous hydrogen, the operation of a fuel cell, and the hushed whine of an electric motor make for low decibels previous reserved for ultra-luxury vehicles.

2016_Toyota_Fuel_Cell_Vehicle_016-1200

CONS

Lack of Refueling Stations
As of this writing, the D.O.E. lists 13 hydrogen refueling stations in the United States. Most of those are not open to retail customers. Several key studies have identified a low number of stations needed to serve the first generation of fuel cell car drivers—and partnerships between carmakers, fuel providers, universities and government entities have outlined an aggressive schedule for building hundreds of stations. However, each station costs about $2 million to $3 million, and the permitting and construction process continues to defy optimistic plans. It could be many years before an H2 station is close to your home. (Meanwhile, EV owners can easily install a home charging station that alleviates the need to travel to any kind of gas or hydrogen station. Just plug in at home.)

Uncertain Well-to-Wheels Advantage
The jury is still out on the energy benefits of hydrogen on a well-to-wheel basis. Jeremy Rifkin, author of The Hydrogen Economy, is sanguine. “Hydrogen has the potential to end the world’s reliance on imported oil,” he said. Studies by the University of California at Irvine states that well-to-wheel emissions for hydrogen vehicles sourced from natural gas are lower than battery electric vehicles, and less than half of equivalent gasoline vehicle emissions. But there are many researchers who disagree. Ford studies conclude that fuel-cell vehicles “do not provide significant environmental benefits on a well-to-wheels basis (due to GHG emissions from the natural gas reformation process).” It’s believed that the entire process of electrolysis, transportation, pumping and fuel cell conversion leaves only about 20 to 25 percent of the original zero-carbon electricity to drive the motor. While a fuel cell system is an efficient powertrain, the bigger energy picture that takes fuel production as well as in-vehicle use, is far from certain. About 95 percent of the hydrogen used today is produced by a process called steam reforming, a process that releases greenhouse gasses. Making a kilogram of hydrogen from water through electrolysis is estimated to require 45 or more kilowatt-hours of electricity, depending on the technology. That’s enough electric to run an EV for a couple hundred miles.

High Cost of Cars
The Toyota Mirai, a midsize sedan that looks like a futuristic Prius, sells for $57,500, or leases at $499 a month. The Honda FCX Clarity, a full-size sedan, and Hyundai Tucson Fuel Cell, a crossover, lease for $600 a month. And the compact Mercedes-Benz F-Cell leases for about $850 a month. These limited-run hydrogen fuel cell cars are the first batch using the new technology. The first drivers are paying a hefty premium to be early adopters. They could pay significantly less, maybe half, to drive similar cars that use conventional or even battery-electric powertrains. Given the small scale of production, expected for at least the next several years, the first buyers and leases of hydrogen cars will pay a handsome premium for the honor—even after incentives and perks (like free fuel) are thrown into the mix.

High Cost of Fuel
The lack of economies of scale not only affects the cost of the cars, but also the fuel. Fortunately, most of the deals on first-generation fuel cell cars will include the fuel. That’s mostly because the systems used to measure and charge for the fuel are not mature, so automakers are making the process easier by providing the fuel at no additional cost. Yet, it’s also clear that hydrogen fuel at the first retail stations is currently going for about $6 a gallon. The carmakers and analysts believe the cost will come down to parity with gasoline in the next few years. If and when that happens, the efficiency of a fuel cell car will give drivers a cost advantage. But in the meantime, hydrogen is the most expensive automotive fuel on the market.

Limited Vehicle Choices
The automotive industry is divided in its outlook on hydrogen fuel cell cars. While nobody wants a battle between hydrogen cars and EVs, there’s a sharp dividing line that has (at this time) four automakers putting out H2 cars: Toyota, Honda, Hyundai and Mercedes. The rest are very much on the sidelines waiting to see if hydrogen fueling infrastructure materializes. Every new technology starts out with a handful of cars—think Honda Insight and Toyota Prius during the early hybrid days, or Chevy Volt and Nissan Leaf in the first year or so of plug-in vehicles. But given the infrastructure challenges with hydrogen, we could see a sustained period in which consumers eager to go H2 have only about four to six vehicles to consider.

 

 

 

 

 

Comment with Facebook

comments

Leave a Reply