Fuel Sustainability Brief: Hydrogen

Why Hydrogen?

Hydrogen fuel cell vehicles (FCV) offer a minimum 40 percent reduction in greenhouse gas (GHG) emissions from diesel, an 85 percent or more reduction when producing hydrogen from biomass using renewable energy.

However, significant cost and technical hurdles remain to make FCVs a commercially viable option for medium- and heavy-duty vehicles.

Market Oulook

The market outlook is much more promising in light-duty than medium- and heavy-duty vehicles given that production costs have dropped more than 50 percent in recent years.¹ Eight automobile manufacturers are commercializing light-duty FCVs, and automakers expect around 50,000 fuel-cell vehicles will be on the road within five years.² Approximately US$1 billion of public funds are invested annually in hydrogen R&D ³

Current market share of FCV in medium- and heavy-duty vehicles is a fraction of 1 percent and is expected to remain low for more than a decade.

Vehicle Applications

The hydrogen FCV is a different technology than the internal combustion engine (ICE) and requires more research and development for medium- and heavy-duty vehicles. Two manufacturers currently produce a tractor powered by hydrogen fuel cell, and several already make transit buses.⁴ The most practical applications of hydrogen in this sector for the medium-term may be for materials-handling vehicles, transit buses, and possibly to extend range of medium-duty battery electric vehicles. Durability of the fuel cell system and volume and weight of hydrogen storage system are constraints that must be addressed for commercialization across other medium- and heavy-duty vehicle types.⁵

Fueling infrastructure in the United States is extremely limited. In 2013, there were an estimated 76 refueling stations in North America, and an additional 68 with capacity to serve 20,000 vehicles are planned for California by 2016.⁶

Key Issues

Key Feedstock Choices

Hydrogen is desirable in part because of feedstock flexibility. With existing technology, hydrogen can be produced from numerous energy resources including natural gas, coal, electricity, and biomass.⁷ Currently the United States produces 9 million metric tons of hydrogen each year for industry and refineries, enough to fuel approximately 35 million FCV automobiles.⁸ Natural gas is used in around 95 percent of U.S. hydrogen production today.

Key Process Choices

Thermochemical hydrocarbon conversion (i.e., syngas) is the process used to produce hydrogen from coal, oil, natural gas, and biomass. Specifically, steam reforming of natural gas is the most common method of hydrogen production in the United States today.⁹

Electrolysis is also a well-established method of producing hydrogen that separates water into oxygen and hydrogen by using an electric current passed through the water. Water electrolysis coupled with a renewable energy source offers one of the lowest GHG processes for producing hydrogen.

Key Sustainability Opportunities and Impacts

Opportunity: Climate Change

Research on GHG benefits of hydrogen from various pathways varies, but most shows a minimum 40 percent reduction from diesel. One commonly cited study shows that production using the dominant industrial pathway from natural gas produces approximately half of GHG emissions as diesel.¹⁰ Some studies suggest it would be near zero emissions, while California’s standard suggests hydrogen from biomass would generate a 63 percent reduction from diesel.^{11 12} Others show reductions of 40-85 percent depending on specific feedstocks and production processes.^{13 14}

Opportunity: Air Polution (Tailpipe)

One significant benefit of hydrogen is its “clean combustion” relative to other fuel types. At the combustion phase, FCV’s are considered zero emissions vehicles since they produce only water and water vapor. This eliminates GHG emissions, particulate matter, NOx, SOx, and other emissions produced by fossil fuel combustion that contribute to human health conditions.

Impact: Air Polution (Feedstock)

The feedstock used to produce hydrogen (natural gas, coal, biomass, etc.) may result in human health impacts from emissions at the production site. Furthermore, the dominant process used to produce hydrogen by steam reforming produces carbon monoxide, which is toxic to humans and a risk for workers in processing plants.

Key Uncertainties and Unresolved Issues

Uncertainty: Feedstock Impacts

As a “feedstock-flexible” technology, many FCV uncertainties and unresolved issues are those associated with the feedstock used for a given fuel pathway. Therefore, life-cycle methane leakage and wellhead community and water impacts are important unresolved issues for natural gas, and indirect land use is an uncertainty for biomass. These are described in more detail in specific BSR Future of Fuels Fuel Briefs on Natural Gas, Electricity, and Biofuels.

Sustainability Potential

Best Case

Hydrogen from biomass offers the ideal option, up to 85 percent lower GHG emissions when produced using renewable energy.¹⁵ Theoretically, hydrogen derived with water electrolysis using zero-carbon electricity could be lower.¹⁶ Hazardous materials management technology and systems would be needed to avoid worker exposure to carbon monoxide when producing hydrogen via steam reforming.

Best Practices

Hydrogen is in early stages of development, so best practices have yet to be developed. However, best practices for avoiding and reducing sustainability impacts of hydrogen feedstocks (natural gas, biomass, electricity, etc.) are better defined. Those practices are detailed in specific BSR Future of Fuels Briefs on Natural Gas, Electricity, and Biofuels.

Adopt Hydrogen for Specialized Applications

Fuel cells are already being used in buses in Europe, the United States and Canada, and parts of Asia.¹⁷ An NREL study found that small fuel-cell units extended range and lowered capital requirements of medium-duty battery electric vehicles.¹⁸ Materials handling vehicles such as forklifts are a unique application that have been commercially viable since 2012.¹⁹

Use Hydrogen for Battery Storage

Hydrogen’s real potential may lie in its attractiveness as a storage option for intermittent renewable energy resources (solar, wind, etc.) integrated with the electrical grid.²⁰ Storage is a key to integration of renewable energy into electricity production given that sources of power such as wind and solar are variable, while electricity generators must provide ongoing energy such that storage bridges the gap. Hydrogen fuel cell technology is one of the most promising low-carbon options to store excess renewable electricity, and projects are already being piloted in Germany and elsewhere.²¹