Hitting the Hydrogen Highway

In early May, I spent a sunny morning in suburban New York driving General Motors' fourth-generation Fuel Cell Vehicle (FCV). With gasoline prices a-soaring and greenhouse gases a-gassing, introduction of even experimental FCVs could not be timed any better. About 45 have debuted so far, all of them experimental.

DN Web Editor Regina Lynch and I traveled to GM’s Training Center in Ardsley, NY just north of New York City. The car is a 2008 Chevrolet Equinox SUV equipped with a 400 fuel cell stack that pumps out 93 kW to power a 123 hp, three-phase electric traction motor. On a full tank of hydrogen – actually the Equinox has three tanks – this FCV has a stated range of 158 miles but has reached 200 on occasion. I was psyched to drive the car of the future, which promises to free us from the lords of oil and produces no CO² or NOx. I am also realistic about substantial and intertwined technical and economic barriers that remain before we can declare oil emancipation day.

GM is well along in its development of hydrogen vehicles. It has built 100 FCV Equinox’s in its joint venture plant with Suzuki in Ingersoll, Ontario as part of Project Driveway to put FCVs into the hands of consumers, celebrities and the media. Half the cars are in the Los Angeles area and the rest are split between Ardsley and Washington. GM’s FCVs that preceded the fuel cell Equinox were the EVI, Opel Zafira FCV and the Chevy Sequel.
 
I loved driving the fuel cell Equinox even though with my kids out of the nest I’d be hard pressed to look at an Equinox SUV. Years ago, I owned an S-10 Blazer, the unrefined truck-like and distant forebear of the Equinox.

The Equinox FCV has direct drive from motor to wheels and no transmission. It produces 230 ft-lb of torque. Officially, GM says it goes 0-60 mph in under 12 sec and tops out at 100 mph. Indeed it does, but this FCV could exceed 100 mph and do 0-60 mph in the five sec I estimate. Electric motors are very powerful and the one in the Equinox is no exception. Acceleration is uniform and silky smooth, seemingly the same at 5 mph as at 50. I topped out at 85 mph crossing the Tappan Zee Bridge on I-87 with GM Engineer Chris Colquitt and Lynch aboard. I figured no ‘statey’ is going to pull over a car whose exterior is decorated with artwork proclaiming its clean hydrogen innards.

The Equinox generates substantial road noise, perhaps because there’s no internal combustion engine (ICE) to muffle it. When idling, there was a steady airy whirring and a click when we braked. GM’s Colquitt said the whirring was probably hydrogen being piped from tanks in the rear to the FC stack under the hood. The differences between the fuel cell Equinox and its gas-powered counterpart should not be considered anything more than quibbles for the short time we drove it. There were few if any compromises or differences except a shorter range, refueling and uncertainty about reliability. GM says the Equinox’s fuel cells will last about 50,000 miles, which needs to be bumped to 150,000 miles. The Equinox we drove only had 2,700 miles on it.

Besides smooth unstepped power directed to the front wheels, the most noticeable difference from the gas-powered car we’d driven to New York were the brakes. The Equinox uses regenerative braking for 75 percent of its stopping ability, meaning it’s provided by resistance from the electric motor. Regenerative braking also sends power back to a nickel hydride battery acting as a backup to the 400 fuel cell stack. The pedal feel is squishier than conventional power brakes until the driver pushes the pedal hard to get the brake pads to clamp down on the rotors.

Lynch and I logged about 60-70 miles on this Equinox and averaged 46-47 miles per kilogram, which is a gallon of gas equivalent known as a GGE. That’s not bad for a 2.7-ton vehicle that can seat four and provides generous cargo space for a small SUV. The Dept. of Energy is shooting for price per kilogram of $2-$3 untaxed.

Starting the car is the same as starting a conventional vehicle. The operator turns a key and waits a few seconds for the tanks to start delivering hydrogen to the fuel cells. Needles on the two largest dash dials – kW x 10 and mph – do a quick 360 and then fall to zero. Then one can hear the gas being transported through the lines to the fuel cell stack. Other instruments are a fuel gauge for hydrogen, a meaningless temperature gauge which is a holdover from the mass-production Equinox, the usual digital odometer and data such as miles per kilogram. A center-dash LCD displays the usual radio station details, AC controls and GPS, but also shows an animation of the hydrogen traveling to the fuel cells, the hydrogen being turned back into water and the electrons traveling to the motor.

One other exterior difference is the air intakes in place of where the fog lights are in the production model. This is to cool the power plant, which operates at much lower temperatures (140-176F) than an internal combustion engine. Cooling is a technical challenge when the engine operates much closer to ambient air temperature, Colquitt says.

The way fuel cells work is simple. First, the hydrogen molecules from water are converted into a gas thanks to electricity separating it from the oxygen molecules (H₂0). This process, known as electrolysis, can be done right at the refueling station, in a large high-volume plant or eventually in your garage when such home electrolysers under development become reality. In the vehicle, the gas is fed into the anode side of the fuel cell where the hydrogen electrons produce electrical current. Meanwhile, hydrogen protons pass through a platinum-plated membrane into the cathode side of the fuel cell, mix with oxygen and revert into a water vapor that is expelled through the car’s exhaust. Hydrogen electrons cannot pass through the membrane and as such remain on the anode side to produce current. (Technically, hydrogen is not a fuel. Rather, it’s an energy carrier that can produce electricity).

In other words, the fuel cells in the Equinox reverse a process that started in Shell’s electrolyser located at the White Plains, NY Dept. of Public Works where the hydrogen was produced. While most hydrogen gas comes from natural gas via a process known as steam methane reforming (SMR), it can be produced virtually anywhere by means of photo electrolysis with water and electricity from the grid or from renewable sources such as a wind turbine. At the White Plains station, the Shell electrolyser station requires anywhere from 55-80 kW-hr (about 1/8th-1/10th of my average monthly household electricity usage) and about 2L of water to produce 1 kg of hydrogen, which equals 1 gal of gasoline in energy density.

However, electrolysers on a mass scale at this point are uneconomic and power hungry. Onsite production in a service station would be hard-pressed to meet the projected 1,500-kg demand for a typical refueling station in a mass market.

We “gassed up” at 7,000 PSI from about half-empty in six to seven minutes. The higher the PSI, the more hydrogen can be compressed into the vehicle’s tanks. The pump also operates at 3,000 PSI for tanks not rated as high as ours and 10,000 PSI pumps and tanks are in the works. The tanks in the Equinox hold about 4.5 kg. An electric cable plugs into a receptacle just below the rear hatch handle and sends data to the pump about the level in the tank. While we filled up, a vigilant infrared detector continually scanned for leaking plumes or heat and would have instantly shut down the pump had it detected escaped hydrogen.

Attaching the pump nozzle was a snap – literally! The operator pulls the plastic cap off the gas filler akin to ones on barbeque grill propane tanks. Then he or she clicks the nozzle onto the filler valve and secures it in place with the nozzle collar. For sure, this is a no-smoking zone, but gasoline, while more volatile, can also be seen and more easily detected. Hydrogen is colorless, evasive and odorless. While videotaping, Lynch had to stand behind a gray line 12 or so feet away because electronic devices cannot be operated near the refilling spot.

Despite all the remaining issues, one wants FCVs to become reality, especially when it comes to exhaust. As we place mandatory limits on greenhouse gas emissions, FCVs will become more attractive and could start appearing for sale between 2010 and 2012. The Equinox has four slots in its lower rear through which exhaust in the form of water vapor is expelled from the power plant. It’s similar to the condensation we produce when breathing in cold weather. FCVs produce zero NOX or CO₂ although there is some relatively minor pollution when doing the “well to wheel” calculation. For example, if there is electricity coming off the grid, the hydrogen still has a carbon footprint.

I love the idea of FCVs and hope the automakers and energy providers can deliver. Assuming reliability, convenience, a fair price and few compromises from what we drive today, which are all big 'ifs,' I’d buy one in an instant.

	GM's hydrogen-powered fuel cell Chevy Equinox. Source: John Dodge

  View more photos in our hydrogen gallery!