How clean are hydrogen fuel cell electric vehicles?

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Long planned and anticipated, the first production-version FCEVs are rolling out and more are on their way, but how clean are they?

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UCSUSA

Long planned and anticipated, the first production-version hydrogen fuel cell electric vehicles (FCEV) are rolling out and more are on their way. Mass-market models from HondaHyundai and Toyota are in the works. They are an important solution — along with plug-in electric vehicles — for reducing our carbon emissions and achieving our goals of putting more zero-emission vehicles on the road. As I have written before, FCEVs have advantages of greater driving range and faster refueling. Questions arise, however, about just how clean these vehicles are if the early models rely on hydrogen produced from natural gas — a fossil fuel.

Like plug-in cars, FCEVs use clean electric motors and produce no harmful tailpipe emissions. Their total emissions, however, depend on how the hydrogen fuel is made and delivered. As demonstrated in a new Union of Concerned Scientists fact sheet, full lifecycle “well-to-wheels” global warming emissions analyses show that even when using hydrogen from natural gas, today’s early hydrogen-powered FCEVs reduce emissions by over 30 percent compared with conventional gasoline vehicles. And in California, with requirements for renewable hydrogen, FCEVs are cutting emissions even more.

40923_1_1.aspxHydrogen fuel can be made from different sources

Currently, most hydrogen is made by converting natural gas into hydrogen gas and carbon dioxide. However, hydrogen can also be produced from lower-carbon sources of energy such as electricity from solar or wind, which can be used to split water into hydrogen and oxygen through electrolysis. Another low-carbon source of hydrogen is methane gas from landfills and sewage treatment facilities, provided that methane leakage is minimized.

While natural gas is likely to be a significant source of hydrogen fuel in the short term, the first vehicles will also use hydrogen from renewable sources. The initial rollout of FCEVs is happening in California due to the state’s investment in hydrogen refueling stations. California law (SB 1505) requires that at least 33 percent of hydrogen produced at these state-supported stations be generated from low-carbon sources, and the state projects that at least 46 percent of hydrogen will come from renewable sources by the end of 2015. This renewable-hydrogen standard will apply to all stations in the state once production of hydrogen reaches 3,500 metric tons per year (enough for about 15,000 cars).

How does the first production fuel cell vehicle stack up?

The first commercially available hydrogen-powered FCEV, the Hyundai Tucson Fuel Cell SUV, produces substantially lower global warming emissions than the Tucson’s gasoline version. This FCEV produces 286 g CO2eq/mile if fueled by hydrogen produced from natural gas, equal to the emissions from a 38-mpg gasoline vehicle. When using hydrogen that meets California’s 33 percent renewable hydrogen standard, the fuel cell SUV emits 202 g CO2eq/mile—the equivalent of a 54-mpg gasoline vehicle, or less than half the global warming emissions of the SUV’s gasoline version. By the end of 2015, California is projected to produce 46 percent of its hydrogen fuel from renewable sources, which would render the Tucson FCEV’s emissions equal to that of a 63-mpg gasoline car.

FCEV-GHG

Future improvements for fuel cell vehicles

Fuel cell vehicles that come to market over the next few years will likely cut emissions relative to gasoline vehicles even more due to advances in fuel cell performance and in automotive technologies such as the electric-drive train, as well as the wider availability of lower-carbon hydrogen. Such evolution has already been the norm among plug-in electric vehicles, including the Nissan Leaf; in just three years on the market, the Leaf lowered its electricity consumption by more than 10 percent, from 0.34 to 0.30 kWh/mile. And because fuel cell vehicles share many components with plug-in electric vehicles, advances such as improved electric motors or more efficient power systems will benefit fuel cell vehicles too. Policies such as those in California, which mandates increases in lower-carbon hydrogen production, will further improve the benefits of switching from gasoline to fuel cell vehicles.

 

Source: UCSUSA. Reproduced with permission.

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11 Comments
  1. DogzOwn 5 years ago

    Each litre of petrol contains 4 times as much hydrogen than each litre of liquid hydrogen. In vehicles, it’s compressed gas not liquid. At ambient temperatures, pressure inside hydrogen tanks is more than 200Bar or 3000psi. Not expected to be at your nearest servo any time soon. Private cars are the problem, not the solution.

  2. juxx0r 5 years ago

    63 MPG for an electric vehicle is rubbish.

    • Miles Harding 5 years ago

      MPG and electric vehicles, how I hate this juxtaposition!
      Really, this is a sleazy attempt by the motoring industry to make their lousy hybrids sound good. The notion that electric energy in a battery and the chemical energy in a fuel tank are directly comparable is bogus. At best, ICEs manage to convert about 30% (physical limit) of the fuel energy into useful work, whereas a good EV drive is 90% or better.

  3. Bob_Wallace 5 years ago

    H2 from renewable electricity would be a zero carbon personal vehicle solution but it would take more than 2x as much electricity per mile. Just based on electricity purchases alone it would cost more than 2x to drive a mile.

    Then add in the infrastructure cost. In the US we have about 168,000 gas stations and a large number of refineries to crack oil into gas and diesel. Were we to drive FCEVs we would need to replace those refineries with hydrogen extraction and compression plants and replace those petroleum stations with hydrogen stations. Add those costs into the >2x electricity consumption.

    Fuel not cheap.

    In exchange what would one get? Quicker refueling stops on a long day drive. If the FCEV driver only refueled and didn’t stop to eat a meal, pee, check messages, etc. they might arrive at their destination a half hour sooner. The typical driver takes long trips like that 4 times a year? Six times a year?

    The rest of the time the FCEV driver is going to have to divert from their route to a H2 station to fill up. Over the year the FCEV driver is likely to spend more time fueling than the EV driver will spend charging since it takes only seconds to plug in and unplug when one parks for the night.

    Plus battery capacity has been increasing at roughly 8% per year. Range differences will tighten over time.

    • Miles Harding 5 years ago

      The beauty of the HCV is the fact that the motorist is forced to buy fuel from the new retail infrastructure instead of being able to charge and make their own fuel at home from PV panels.

      I doubt that EV range will ever eclipse that of the ICE, simply because the liquid fuels are so very energy dense. Current EVs are very good at metropolitan trips, but aren’t very compatible with long drives. Fortunately, most trips are short and eminently EV compatible. For those longer trips there are alternatives, like DC fast charging, which can add 100km of drive range in about 20 minutes, or diesel hybrids. Provided the number of diesel trips is sufficiently low, bio-fuels would be effective in the long term.

      • Bob_Wallace 5 years ago

        Somehow this idea of energy density has been pushed to the forefront by fossil fuel and nuclear interests, I would suppose. Energy density is one part of a formula, the solution of which gives one the price of electricity or kinetic energy. Source energy density can be high but if the method of converting that energy is either inefficient or expensive then the outcome is not price competitive.

        Gasoline is energy dense. The internal combustion engine is incredibly inefficient. Kinetic energy from the ICE is expensive when compared to EVs.

        Uranium and thorium are energy dense. A nuclear reactor is incredibly expensive to build. The electricity from a nuclear reactor is expensive compared to wind and solar.

        Thus ends my morning rant….

        EVs and range. How much range do ICEVs commonly have? Tesla is offering a 400 mile range battery for their Roadster and will be releasing a Model S with a 500 mile range.

        We should see affordable 200 mile range EVs in the next couple of years. Battery capacity has been improving at about 8% per year. If that progress continues those 200 mile battery packs would be 400 mile battery packs in less than a decade. And, my guess, we’ll likely see things progress faster with all the research that is now going on.

  4. Michel Syna Rahme 5 years ago

    Obviously the end goal was and always is Hydrogen generation from clean sources.
    In the meantime, one source that can be added to the list above during the interim if I remember correctly is Hydrogen currently being used from industrial waste in Germany to power Munich airports fleet

  5. Tony Pfitzner 5 years ago

    Hydrogen is a green house gas.

    It’s low molecular weight means that it migrates directly to the stratosphere where it reacts with hydroxyl radicals to form water vapour. The problem with this is that hydroxyl radicals are important in scrubbing methane from the atmosphere.

    Hydrogen, again because of it’s low molecular weight, is extremely difficult to contain. A large scale deployment of hydrogen fuel cell power would necessarily result in hydrogen leakage, particularly in third world countries where maintenance standards are likely to be low.

    The scenario outlined in this article seems like a genuinely bad idea for the global environment compared to a combination of solar power and batteries.

  6. Bob Fearn 5 years ago

    Compared to an electric car charged by your own solar panels the hydrogen car is an expensive step backwards. Why people and companies support a step backwards is a mystery to me.

    • Miles Harding 5 years ago

      For much the same reason that the LNP supports coal?

  7. Motorshack 5 years ago

    There’s an unspoken assumption in most of these comments, which is that a single type of vehicle should meet all the transportation needs of a given person or family.

    In fact, this is a horrible constraint to put on both the design of the transport system and the budgets of individuals. The only reason that anybody thinks this way at all is because the auto industry has spent a century pushing the idea, in order to sell as many cars as possible.

    In my own case, I use a bicycle to get around town the vast majority of the time, and I only use anything else when either I have something large to move, or the distance from home is more than five or six miles.

    On those rare occasions there is a wealth of possibilities that are quite practical, and most people are well aware of them: borrowing a car, taking a cab, bus or train, renting a car or truck, etc.

    The main point is that by considering other options you can choose the most cost-effective one for any given trip, and thereby avoid both thousands of dollars in costs and tons of greenhouse gas emissions.

    Of course, this does require that people actually think about what they are doing, instead of reflexively jumping in the car. Apparently this too is a serious constraint on the development of a rational transport system.

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