SEPTA Hydrogen Bus Project
Pilot/Test Project
The Southeastern Pennsylvania Transportation Authority’s (SEPTA) Hydrogen Bus Project is a pilot project that implements the use of 10 hydrogen fuel cell powered buses beginning in the fall of 2024. From April 2024 through to the fall of 2024, SEPTA states they will be “piloting” the hydrogen buses but it is unclear exactly what that means. SEPTA states that from the fall of 2024 on, the buses are expected to be put into operation in the city for a pilot or test period. During this same period, 10 New Flyer fully electric buses will also be tested. These buses will be operated on various routes around the city of Philadelphia for the next year. The testing period will culminate in approximately the fall of 2025, at which time it is expected that SEPTA will decide which technology to proceed with in the future to power its bus fleet (either hydrogen fuel cell or fully electric or both).
This is part of SEPTA’s larger strategic plan to have a zero-emissions bus fleet in place by 2045. The current bus fleet, powered by diesel fuel, will be phased out or converted to alternative power sources beginning in 2025. The 10 hydrogen fuel cell powered buses in the pilot program will operate out of the Midvale bus depot located at 2401 Roberts Ave. in Philadelphia. The hydrogen will be produced using electrolyzers and shipped approximately 800 miles via electric trucks from Tennessee in containers as a crypto-temp liquid. At the Midvale bus depot, the liquid hydrogen will be warmed to a compressed gas that feeds the fuel cells to power the bus. While in use, the hydrogen gas will be carried in canisters on the roofs of the buses.
Expanded Plans at Build Out
The pilot program is just the start of SEPTA’s hydrogen bus plans. A 2023 feasibility study outlined plans to convert SEPTA’s bus terminals into hydrogen storage and refueling stations to serve its hydrogen-powered bus fleet. The report claims that liquid hydrogen storage and fueling for their bus fleet is feasible at six of their eight bus depots. The hydrogen fueling scenario assumed for each site involves purchase by SEPTA of liquid hydrogen, to be delivered to each site by tanker truck. At each depot the liquid hydrogen would be transferred from the tanker truck to an on-site liquid storage tank(s) with capacity for 1 – 2 days of bus fueling.
Between four and ten tanker truck deliveries of liquid hydrogen would be required per week depending on the depot. The liquid hydrogen would be pumped from the storage tank(s), evaporated, and delivered to on-bus hydrogen tanks as a high-pressure gas via one or more hydrogen dispensers. SEPTA’s largest depot (Midvale) would require 45,000 gallons of liquid hydrogen storage (3 tanks). The estimated cost of installing the hydrogen storage and fueling infrastructure ranges from $6.5 million at the smallest depot to $16.1 million at the largest depot.
Why should I be concerned?
Hydrogen gas is highly flammable and burns with an almost invisible flame in addition to being colorless, odorless, and tasteless. The flammability and potentially explosive attributes of hydrogen makes it very dangerous to handle, transport, and store. The lack of a visible flame, odor, or taste makes it very hazardous for workers and any residents in the vicinity because they would be unaware when a release has occurred.[1]
Hydrogen gas contains the smallest and lightest molecule, which increases the probability of leaks through small holes and materials. In other words, due to its low viscosity, hydrogen is much more prone to leak from infrastructure than other hydrocarbons. Hydrogen leaks approximately three times faster than natural gas and five times faster than propane on a volumetric basis.[2] Fires and explosions have occurred in various components of hydrogen systems as a result of leaks that can quickly meet a variety of ignition sources.