Benefits and Challenges
Less Greenhouse Gas Emissions
Gasoline- and diesel-powered vehicles emit greenhouse gases (GHGs), mostly carbon dioxide (CO2), that contribute to global climate change. Fuel cell vehicles (FCVs) powered by pure hydrogen emit no GHGs from their tailpipe, only heat and water.
Producing the hydrogen to power FCVs can generate GHGs, depending on the production method, but much less than that emitted by conventional gasoline and diesel vehicles. more...
The chart below shows the GHGs generated by various vehicle types and considers all steps of the energy chain from fuel extraction or production to fuel use by the vehicle, not just tailpipe emissions. Even when accounting for the GHGs emitted during hydrogen production, conventional gasoline vehicles generate roughly 2 to 12 times more GHGs per mile than fuel cell vehicles.
Reduced Oil Dependence
FCVs could reduce our dependence on foreign oil since hydrogen can be derived from domestic sources, such as natural gas and coal, as well as renewable resources such as water, biogas, and agricultural waste. That would make our economy less dependent on other countries and less vulnerable to oil price shocks from an increasingly volatile oil market.
Less Air Pollutants
Highway vehicles emit a significant share of the air pollutants that contribute to smog and harmful particulates in the U.S. FCVs powered by pure hydrogen emit no harmful pollutants. If the hydrogen is produced from fossil fuels, some pollutants are produced, but much less than the amount generated by conventional vehicle tailpipe emissions.
Fuel cell vehicles are not yet commercially available, but a few hundred are being evaluated in field tests. Several challenges must be overcome before fuel cell vehicles (FCVs) will be a successful, competitive alternative for consumers.
FCVs are currently more expensive than conventional vehicles and hybrids, but costs have decreased significantly and are approaching DOE's goal for 2017 (see graph). Manufacturers must continue to lower production costs, especially for the fuel cell stack and hydrogen storage, for FCVs to compete with conventional technologies.
Onboard Hydrogen Storage
Some FCVs store enough hydrogen to travel as far as gasoline vehicles between fill-ups—about 300 to 400 miles—but this must be achievable across different vehicle makes and models and without compromising customer expectations of space, performance, safety, or cost. more...
FCVs are more energy efficient than conventional cars, and hydrogen contains three times more energy per weight than gasoline does. However, hydrogen gas contains only a third of the energy per volume gasoline does, making it difficult to store enough hydrogen to go as far as a gasoline vehicle on a full tank—at least within size, weight, and cost constraints.
The following storage methods are being explored:
As a gas in high-pressure tanks. Current FCV designs use high-pressure (5,000- to 10,000-psi) tanks to store hydrogen. These systems are large, heavy, and costly, but they are the most cost-effective solution in the near term.
As a liquid at sub-zero temperatures (-423°F). Since hydrogen is densest as a liquid, this method allows more hydrogen storage than gaseous high-pressure storage. Issues with liquid storage include hydrogen boil-off, the energy required for hydrogen liquefaction, volume, weight, and tank cost.
Materials-based storage. Hydrogen can be stored on the surface of solids (by adsorption), within solids (by absorption), and through chemical reactions. Materials-based systems have the potential to be small and lightweight and may prove to be the best solution in the long term. However, they are still in the early stages of development.
For more information about hydrogen storage, visit the following EERE Fuel Cell Technologies Office web pages:
Fuel Cell Durability and Reliability
Fuel cell systems are not yet as durable as internal combustion engines, especially in some temperature and humidity ranges. Fuel cell stack durability in real-world environments is currently about half of what is needed for commercialization. Durability has increased substantially over the past few years from 29,000 miles to 75,000 miles, but experts believe a 150,000-mile expected lifetime is necessary for FCVs to compete with gasoline vehicles.
Getting Hydrogen to Consumers
The current infrastructure for producing, delivering, and dispensing hydrogen to consumers cannot yet support the widespread adoption of FCVs. In 2013, H2USA was launched as a public-private partnership between DOE and other federal agencies, automakers, state government, academic institutions, and additional stakeholders to coordinate research and identify cost-effective solutions for deploying hydrogen infrastructure.
Fuel cell technology must be embraced by consumers before its benefits can be realized. As with any new vehicle technology, consumers may have concerns about the dependability and safety of these vehicles when they first hit the market. Plus, they must become familiar with a new kind of fuel. Public education can accelerate this process.
For more information on the status of fuel cell development, see the following resources:
- Progress and Accomplishments in Hydrogen and Fuel Cells. EERE Fuel Cells Technologies Office, U.S. Department of Energy. March 2013.
- EERE Fuel Cells Technologies Office (Home Page)
- EERE Fuel Cells Technologies Office: Accomplishments and Progress