In the coming year, vehicles powered by fuel cells are expected to come to market in the United States, first in California and subsequently in other regions. Fuel cells are a technology that uses hydrogen to generate electricity. A fuel cell vehicle (FCV) uses this electricity to run the motor. FCVs have environmental benefits because they emit no local pollutants and the only direct by-product is water. However, the production of hydrogen can result in greenhouse gas (GHG) emissions. These emissions must be evaluated to understand how compatible they are with New England’s short-term and long-term GHG reduction targets (80% by 2050).
Hydrogen from Fossil Fuels or Renewables?
The most economical method for producing hydrogen today is steam reforming of methane. In this process, a byproduct of the hydrogen production is carbon dioxide–a greenhouse gas. In addition, there can be GHG emissions associated with the energy source used to create the steam, such as the combustion of fossil fuels. Chart 1 (below) shows the GHG emissions from a FCV using hydrogen derived from a steam reforming process that combusts natural gas as the energy source. These emissions are compared with a battery electric vehicle and a plug-in hybrid using the electricity grid mix in New England along with a traditional gasoline vehicle. This shows that a FCV can have 39% fewer GHG emissions than a gasoline vehicle, while a battery electric vehicle typically has 60% fewer GHG emissions than a gasoline vehicle. Cleaner methods of hydrogen production do exist. One common method—electrolysis–uses electricity to split a water molecule and produces only hydrogen and oxygen as a byproduct. This method has zero process emissions and, just like electric vehicles, the electricity used can be renewable, with zero GHG emissions.
Ensuring FCVs Integrate into a Clean Energy Future.
The key question is how to ensure that hydrogen production uses cleaner methods in a manner consistent with our GHG targets. In New England, our pre-dominant transportation fuels are not covered by a greenhouse gas policy. Policy solutions do exist across the country: California is now covering all sectors of the economy with a cap-and-trade program, including transportation. That state has specific requirements for hydrogen from renewable sources and encourages cleaner hydrogen with the Low Carbon Fuel Standard. New England states should adopt an appropriate combination of these policies to integrate FCVs into our clean energy future and ensure that our short-term and long-term GHG goals are met.
For more info see: Fuel Cell Vehicles GHG from Hydrogen Production