California’s transportation sector is responsible for more than 40% of the state’s greenhouse gas emissions — even before adding “upstream” emissions from fuel extraction and refining. To reduce greenhouse gas and criteria air pollutant emissions from transit vehicles, the California Air Resources Board adopted its Innovative Clean Transit (ICT) regulation in December of 2018. The ICT regulation requires that by 2029, all new buses purchased by transit agencies in the state must be zero emission. The goal of the ICT regulation is a complete conversion of all public bus fleets to zero-emission buses by 2040. The regulation includes multiple bus types: standard, articulated, over-the-road, double-decker, and cutaway buses.
The Humboldt Transit Authority (HTA) serves multiple small cities spread across hundreds of miles along California’s rural north coast. HTA has been at the forefront of efforts to comply with the ICT regulation. HTA brought its first battery electric bus online in June 2019, and added two more in 2022. These buses operate well on short urban routes in the neighboring cities of Eureka and Arcata. Attempts to operate battery electric buses on longer, more demanding Redwood Transit System routes – including the region’s primary intercity route, from Trinidad to Scotia – were unsuccessful. The driving range was less than anticipated and was especially compromised during winter when both the electric heater and defroster were operated.
Hydrogen fuel cell electric buses
To service its more demanding routes — including a recently introduced North State Express: Route 101 service to Ukiah — HTA turned to fuel cell electric bus (FCEB) technology. FCEBs have a significantly larger range than battery electric buses, and have the added advantage of utilizing fuel cell waste heat for bus heating and defrosting.
The Schatz Center is partnering with HTA to aid in their transition to FCEBs, utilizing our decades of experience with hydrogen and fuel cell technology. Together, we wrote a successful $39M grant proposal to California’s Transit and Intercity Rail Capital Program (TIRCP) to fund the purchase of 11 new FCEBs, as well as a hydrogen fueling station that will be constructed on HTA’s corporation yard, and new transit center in downtown Eureka. Our work included due diligence on bus technologies and working with bus manufacturer New Flyer on a new, more powerful FCEB.
HTA’s pilot FCEB was delivered in March of 2025. To ascertain that the bus met its operating specifications, we developed a rigorous testing protocol. We tested the bus over six increasingly demanding routes, culminating in the 320-mile round trip to Ukiah. Bus performance exceeded our expectations; our testing report can be found here. We will also be responsible for acceptance testing of the remaining 10 buses as they arrive during 2026.
Linde Engineering North America is now under contract for both the station development and associated liquid hydrogen deliveries. The station design includes an 18,000 gallon cryogenic storage tank, which will provide a buffer against supply disruptions.
As HTA’s consulting engineers for the hydrogen station design and installation, we will oversee the station’s construction and performance testing. As part of that work, we have contracted with the Hydrogen Safety Panel — a national organization originating at Pacific Northwest National Lab — to ensure that the station’s design conforms to industry standards and will be safe.
Project completion is slated for December 2026.
