Picture a couple of semitrucks hauling cargo down a highway. Do you see clouds of black smoke left in their wake?
No, you don’t. These trucks are powered by hydrogen fuel cells. The only waste product is water.
Hydrogen fuel cell motors are powered by hydrogen to create electricity for cars and trucks. Unlike solely electric vehicles, which can take eight hours to charge a sedan, hydrogen fuel cell motors can be refueled as quickly as a regular gasoline vehicles and drive for just as long.
The U.S. transportation industry is the nation’s largest generator of greenhouse gases, accounting for nearly one-third of climate-warming emissions. So as the automotive industry seeks greener alternatives to combustions engines, hydrogen fuel cells promise a clean, efficient alternative.
Hydrogen fuel cells could one day power planes, ships and trips to the grocery store. But the transition from the combustion engine to fuel cell motors faces an infrastructure hurdle. Namely, the U.S. hasn’t developed the infrastructure to make fuel cell-powered cars a reality. Across the country, there are fewer than 50 hydrogen refueling stations, which fuel cells cars need to fill their tanks, with virtually all in California.
But commercial semitrucks could be the catalyst. Transitioning these trucks to clean energy would cut about 20 percent of transportation-related greenhouse gases in the U.S. For this reason, developing a dependable, long-lasting hydrogen fuel cell for trucks is the focus of a new Department of Energy consortium called the Million Mile Fuel Cell Truck, known as M2FCT, which is co-led by Los Alamos National Laboratory and kicked off at the beginning of the new year. Funded by the Department of Energy’s Hydrogen and Fuel Cell Technologies Office within the Energy Efficiency and Renewable Energy Office, M2FCT will focus on fuel cell durability, performance, and cost to better position fuel cell trucks as a viable option in the long-haul trucking market.
Here’s how a hydrogen fuel cell engine works: The hydrogen is stored in the truck’s equivalent of a gas tank. As the hydrogen is fed into a stack of fuel cells, it’s combined with oxygen (from air) and converted into electrical energy, heat and water. The truck is also equipped with a power module to distribute the electricity throughout the vehicle, including the electric motor, a battery to supply extra torque and to store energy from regenerative braking, as well as a radiator to dissipate heat from the electrochemical reactions.
A solely electric motor has its advantages among clean-energy alternatives. But the time it would take to charge the massive lithium ion batteries needed for semitrucks make it infeasible. For long, continuous operations, such as trucking, fuel cells can deliver higher efficiency, reduced emissions, higher torque, and no noise pollution.
Additionally, creating the infrastructure for hydrogen fuel cells could be expanded more quickly than the one needed for electric-powered vehicles. The hydrogen refueling infrastructure in California could be leveraged and expanded. Hydrogen refueling stations could be built on a handful of the most-used routes, like Interstate 40.
Not surprisingly, semitrucks are tough on their engines, averaging about 45,000 miles a year. They need to last about one million miles over their lifetimes. The hydrogen fuel cells would need to last just as long, too, and this is what M2FCT is exploring.
In a typical diesel engine, constant detonations that drive pistons and turn the wheels wear the engine down over time. Hydrogen-powered electric motors don’t burn fuel, but they are subject to wear and tear nonetheless, over time becoming less efficient. M2FCT aims to change that.
The platinum-coated membranes are the main
culprits for wear on a hydrogen fuel cell. These are 10- to
20-micron-thick membranes located in the fuel cell chamber, where oxygen and hydrogen react and where the platinum membranes help strip electrons from hydrogen atoms. The resulting electricity powers the vehicle. But the heat generated from this process can cause the platinum-coated membranes to degrade.
Because of the impracticality of testing hydrogen fuel cells for a million hours to recreate wear on the engine, researchers in Los Alamos will use accelerated stress testing to reproduce the punishment on fuel cells from driving. This sped-up stress test generally involves adding heat and gases that speed the deterioration process. Already, the research has produced a couple of insights, including that altering the microscopic structure of the platinum catalyst can reduce the metal’s deterioration. Los Alamos scientists also introduced a benign material into the fuel cell chamber that can capture the harmful chemicals that typically degrade the membrane, extending the fuel cell’s life.
While Los Alamos National Laboratory focuses on efforts to commercialize hydrogen fuel cells for heavy duty applications, a second Department of Energy National Lab consortium funded by the Hydrogen and Fuel Cell Technologies Office within the Energy Efficiency and Renewable Energy Office is refining the process of splitting water into hydrogen and oxygen through electrolysis, called H2NEW. This process will enable affordable and efficient production of hydrogen.
With these projects working concurrently, a new breed of clean-energy semitrucks may soon quietly share the highways of America with you.
Rod Borup is co-director of the Million Mile Fuel Cell Truck and Los Alamos National Laboratory’s program manager for fuel cells and vehicle technology.