PDX and PNNL Explore Hydrogen Fueling for Hazard Resilience

Portland International Airport (PDX) has recently introduced a range of improvements to its operations, and the airport’s eye to the future is turning toward its ground transportation. Now, PDX, Pacific Northwest National Laboratory (PNNL), and Sandia National Laboratories (SNL) are exploring the feasibility of hydrogen fuel for the PDX bus fleet—an idea that could have novel benefits for hazard resilience, particularly for an airport in an earthquake zone.

Getting down to bus-iness

Like any major airport, PDX—which hosts tens of thousands of air travelers a day—has demanding transportation needs. To meet those needs, PDX currently operates a fleet of a couple dozen compressed natural gas buses as parking shuttles. They run 24 hours a day, seven days a week. 

In this collaborative project, PNNL and SNL researchers are conducting a first-of-its-kind, in-depth study on the feasibility of deploying 28 fuel cell electric buses (FCEBs) at PDX. The assessment is exploring how the buses and on-site hydrogen systems would meet requirements and withstand conditions ranging from the everyday to the extreme.

But why consider switching to hydrogen in the first place?

For PDX’s use case, hydrogen fuel cells (which combine hydrogen with oxygen to produce electricity) offer two intriguing advantages: first, burning hydrogen produces only energy and water vapor; and second, FCEBs directly convert that energy into electricity—which means the buses could also be used for purposes other than transportation.

Shaking things up

PDX has a consideration that most airports don’t. Portland is in the Cascadia subduction zone, which means there is a chance that at any time—with little warning—the airport may withstand a catastrophic earthquake.

“In the event of a high-magnitude earthquake, our goal is for PDX to be able to help our region recover, providing important facilities and services to first responders and civilians,” said Danelle Peterson, program development manager at the Port of Portland.

To that end, PDX is proactively developing a range of capabilities aimed at disaster resilience, such as a seismically resilient south runway.

Another one of PDX’s emergency preparedness goals is to enhance its distributed energy system and provide emergency backup power to its critical facilities; this is where the buses come in.

From bus to backup

Because FCEBs directly produce electricity, PDX, PNNL, and SNL are exploring whether they could also serve as giant, mobile backup generators during earthquakes and other hazards.

“Fuel cell electric buses could be used as emergency generators for many essential purposes at airports,” said Arun Veeramany, a senior data scientist at PNNL and principal investigator for the project. While he cautioned that there would be logistical hurdles to clear, Veeramany highlighted a series of backup power needs that could be assisted, in part, by the buses—everything from landing lights to the airport’s terminal and rental car center. 

“Unlike conventional backup generators, FCEBs (depending on the condition of drivable surfaces) can be relocated to meet the needs of the moment—a major boon during a disaster for airports like PDX that have big footprints,” he explained. “And unlike conventional backup generators, the FCEBs would also serve an essential day-to-day purpose for the airport during normal operations.”

The researchers are conducting a hazard assessment for all the equipment and connections that would be involved in providing backup generation via FCEBs, as well as assessing regulations, codes, and standards to ensure that any implementation would be up to snuff.

The researchers plan to deliver the final study to PDX soon. The airport will consider their findings, then will evaluate whether to pursue a switch to hydrogen buses.

“New technologies like hydrogen fuel have so much potential to advance the airport environment," said Andrea Caudill, energy consultant at the Port of Portland. "These findings will be critical to help us assess what alternative energy sources make sense for PDX, but also how they could be applied across the sector. "

“We’re excited to showcase a scenario where hydrogen fuel could add reliability and resilience to our nation’s critical infrastructure,” Veeramany added. “Whether or not PDX ends up implementing hydrogen buses, this analysis is laying crucial groundwork for airports across the country to understand not only the risks, but also the potential rewards, of hydrogen fuel.”

This research was supported by the Department of Energy Hydrogen and Fuel Cell Technologies Office.