Hydrogen fuel cell electric vehicles (FCEV) were the belles of the ball at recent auto shows in Los Angeles and Tokyo, and researchers at the Energy Department's National Renewable Energy Laboratory (NREL) continue to play a key part in improving performance and durability while driving down costs.
Robot Tests Resiliency of Hydrogen Refueling
A bright yellow robot the size of a power forward bends and twists a hydrogen fueling hose hundreds of times a day, testing the durability of the hoses that someday soon will refuel America's hydrogen vehicles.
The robot is the colorful keystone of the hose reliability project at the Energy Systems Integration Facility (ESIF), the newest building at the Energy Department's National Renewable Energy Laboratory (NREL).
With a long arm where its nose should be, the robot simulates the bending and twisting that humans do when they refill their gasoline engines today, and what they'll do in slightly different fashion in 2015 and beyond as car manufacturers bring vehicles powered by hydrogen fuel cells to market.
The robot has a twisty wrist that can turn the hose assembly deftly onto a pin to mate with the vehicle's exterior where the refueling will happen. The repetitive motion puts stress on the hose, so researchers can identify opportunities to increase the lifespan and reduce the cost of the hose assembly. The test also includes low-temperature and pressurized hydrogen gas conditions that will be part of the real-world refueling process.
NREL Senior Engineer Kevin Harrison notes that today's gas stations use the same hoses for thousands of fill-ups before they need to be replaced, and hydrogen fuel cell stations will need to reach that same level of reliability with their hose assembly. "This is a matter of adding value and working with industry to reduce the cost of the hose and the hydrogen infrastructure in general," Harrison said. "This facility [ESIF] allows industry to perform testing they can't do anywhere else in the world."
The driving public has long been tantalized by the allure of a vehicle that emits nothing but water from its tailpipe, but now that Toyota, Hyundai, and Honda have all committed to putting them on the market by 2015, the stakes have changed.
It's one thing for the automakers each to sell 1,000 or so cars the inaugural year, but quite another to ramp it up to 10,000 and beyond until these cars are an appreciable percentage of the marketplace.
Sunken engineering costs and the drive to improve economics through economies of scale are challenges for any new vehicles introduced to the market, including early internal-combustion hybrids, said Bryan Pivovar, fuel cell group manager in the Chemical and Materials Sciences Center located at NREL's Energy Systems Integration Facility (ESIF). But, no one doubts that the Prius is now a success — not just in being the best-selling hybrid on the market, but by enhancing Toyota's image as a green company and technology leader, he added.
Fuel cell electric vehicles could follow that same trajectory, but they have an extra hurdle to clear. They won't become commonplace until there's an infrastructure of fueling stations — and only a fraction of what is required has been built so far. "Nobody wants to have a hydrogen fueling station if there aren't enough fuel cell cars to support it," Pivovar said. Likewise, auto manufacturers are reluctant to go into full-scale production if there aren't enough places to fill up. "It's a chicken and egg scenario."
Andrew Bermingham, left, fills up his Mercedes-Benz B-Class F-CELL car with hydrogen with the help of NREL's Mike Peters at NREL's National Wind Technology Center. Toyota, Hyundai, and Honda all have committed to putting fuel cell vehicles on the market by 2015. Credit: Dennis Schroeder, NREL.
Cleaner Fuels a Research Priority at Energy Department
NREL hydrogen researchers are working with auto manufacturers, component vendors, and others to take a hard look at both the infrastructure and the cost challenges. NREL's new ESIF includes 7,000 square feet of lab space built for hydrogen and fuel cell research. Approximately 50 researchers contribute to hydrogen or fuel cell related tasks, including production, storage, codes and standards, technology validation, and analysis.
Researchers at NREL are examining the best ways to create hydrogen via electrolysis using wind and solar power. The most common way to produce hydrogen today is through steam reforming of natural gas — a tried-and-true approach, but one that generates greenhouse gases.
Just a few months ago, the Energy Department's Fuel Cell Technologies Office, within the Office of Energy Efficiency and Renewable Energy, which supports NREL's research at the ESIF, announced more than $7 million for projects in Georgia, Missouri, Pennsylvania, and Tennessee that will help bring cost-effective, advanced hydrogen and fuel cell technologies to market faster. In the past five years, fuel cell durability has doubled; since 2005, the amount of expensive platinum needed in fuel cells has fallen by 80 percent, according to the Energy Department.
NREL research scientist K.C. Neyerlin applies catalyst layers to a fuel cell through a spray process that delivers a more even distribution of material, improving performance. Credit: Dennis Schroeder, NREL.
Pivovar predicts that hydrogen fuel cell vehicles will take off first on islands such as Hawaii or Japan where a car can't get too far away from the nearest refueling station and fuel costs are often higher, and metropolises such as Los Angeles where smog provides an extra incentive for clean engines. "The motivations for cleaner engines often rise from local concerns, rather than global concerns."
NREL is analyzing the barriers and costs associated with installing enough hydrogen refueling stations to make fuel cell vehicles viable. One intriguing shortcut is to use existing natural gas lines to distribute hydrogen. Studies are exploring limiting hydrogen concentrations to less than 15 percent of the gas in the lines to avoid issues such as hydrogen embrittlement and to reduce the high capital costs of installing completely independent infrastructure.
Lowering the Amount of Platinum Key to Lowering Cost
The NREL fuel cell group has a strong focus on helping lower the cost of fuel cells. One important avenue is to decrease the amount of the precious metal platinum used in the fuel cell. Platinum plays a key role as a catalyst for the electrochemical reactions that occur in a fuel cell that convert hydrogen and oxygen into electricity, heat, and water.
Preparing for the day when hydrogen fueling stations may be as common as gas stations, NREL research engineer Kevin Harrison uses a robot to simulate hydrogen refueling. The robot can simulate the refueling of a vehicle hundreds of times a day. Credit: Dennis Schroeder, NREL.