Interest in hydrogen fuel cells as a sustainable source of clean energy is on the rise globally, and hydrogen fuel cells are widely seen as a viable, zero-emission option to power trucks, trains, ferries, and passenger vehicles.
The heavy-duty vehicle (HDV) market could prove to be ideal for fuel cell development and deployment. Hydrogen fuel cells are well-suited for this market because of their fast refueling time and long driving range. They also contain a higher amount of energy-per-unit mass than a lithium battery or diesel fuel. By increasing the size of the hydrogen tank, a truck can have a higher amount of energy available without significantly increasing the weight – an important consideration for long-haul trucks that have strict weight penalty policies.
Last year, the Department of Energy’s (DOE’s) Hydrogen and Fuel Cell Technologies Office (HFTO) launched the Million Mile Fuel Cell Truck Consortium (M2FCT) to leverage the potential opportunity fuel cells in the HDV market and to align with the H2@Scale vision for clean and affordable hydrogen across multiple sectors in the economy. M2FCT will work on fuel cells for heavy-duty fuel cell trucks that can meet all of the efficiency, durability, and cost requirements of the trucking industry. With $50 million funded by DOE HFTO over five years, a team of five national labs co-led by Lawrence Berkeley National Laboratory (Berkeley Lab) and Los Alamos National Laboratory (LANL) have set out with a 2030 goal of demonstrating systems that have a 25,000-hour, or 1-million mile, lifetime for long-haul trucks.
The M2FCT team outlined the current and future prospects and challenges of hydrogen fuel cells for heavy-duty vehicles, including trucks, buses, trains, and marine applications, in a recent Nature Energy study. Co-authors included scientists from Oak Ridge National Laboratory (ORNL), National Renewable Energy Laboratory (NREL), Argonne National Laboratory (ANL), LANL, and Berkeley Lab.
“The heavy-duty vehicle market could be an avenue to get fuel cell technology deployed quickly,” said LANL Program Manager Rod Borup, the co-director of M2FCT and former director of the FC-PAD (Fuel Cell Performance and Durability) consortium, which was focused on fuel cells for the light-duty vehicles. “This will encourage building the needed hydrogen refueling infrastructure with less infrastructure investment since trucks travel predictable routes.”
“Transitioning to hydrogen fuel cell heavy-duty vehicles would have a significant impact on reducing greenhouse gas emissions,” said Berkeley Lab scientist Ahmet Kusoglu, corresponding author of the study. Kusoglu notes that heavy-duty vehicles make up a small fraction of the vehicle fleet in the U.S. and travel only 10% of the total annual vehicle miles driven, but, according to the Environmental Protection Agency, contribute to 23% of transportation emissions of greenhouse gases in the U.S. Moreover, HDVs account for almost one-quarter of the fuel consumed annually in the U.S.
“The sudden growth in interest in hydrogen as a fuel for HDV necessitates a rapid expansion in research and development (R&D) aimed at extending the durability of fuel-cell components,” said ORNL scientist David Cullen, the study’s first author.
In late 2019, DOE’s HFTO and Vehicle Technologies Offices released technical targets for hydrogen-fueled long-haul tractor trailer trucks, also known as Class 8 long-haul trucks. These targets set in motion the work M2FCT researchers are now embarking on by guiding early stage R&D. The study recently released by M2FCT uses Class 8 long-haul trucks as a case study to show how different design characteristics impact efficiency and durability, as well as how the advancements made for light-duty vehicles can be leveraged to meet heavy-duty vehicle requirements.
Hydrogen fuel cells generate electricity through an electrochemical reaction between hydrogen and oxygen, which combine to generate electricity, heat, and water. One fuel cell can generate about 300 watts of power, so in order to generate enough power to run a car’s electric motor, the fuel cells need to be combined in series into a fuel cell stack.
To meet DOE’s targets for hydrogen-fueled long-haul tractor trailer trucks, M2FCT researchers have identified the key differences between designing hydrogen fuel cells for light-duty vehicles versus heavy-duty vehicles. Challenges, according to ANL chemist Deborah Myers, are that “heavy-duty vehicles require a higher cell voltage to achieve optimal efficiency in addition to the three to five times longer required lifetimes compared to light-duty vehicles, placing greater demands on the performance and durability of the fuel cell materials.” Solutions to this include materials research that explores how existing fuel-cell component materials operate and degrade under different temperature and humidity levels and at higher cell voltages, and development examines how the integration of new materials can meet these challenges.
The M2FCT consortium brings together different areas of expertise related to fuel-cell efficiency and durability and harmonizes activities with industrial developers. While the initial focus of this study is on how to meet the targets for hydrogen-fueled long-haul tractor trailer trucks, M2FCT researchers are also optimistic about the potential adoption of hydrogen fuel cells in other, more demanding heavy-duty applications including trains, maritime, and even aviation.
“The energy, power, and lifetime demands of these applications make fuel cells a very compelling route for their decarbonization, assuming the use of renewably sourced green hydrogen, and should increase the utilization and deployment of hydrogen in multiple sectors,” said Berkeley Lab scientist and M2FCT Co-Director Adam Weber.
This study was supported by DOE’s Hydrogen and Fuel Cell Technologies Office through the Fuel Cell Performance and Durability (FC-PAD) and Million Mile Fuel Cell Truck (M2FCT) consortia.