Hydrogen As Fuel In The Transit Space

As an engineer, I view all my knowledge as a tool to address a problem or improve the efficiency of an existing process. Hydrogen, to me, plays a similar role in multiple industries. Whether it’s aerospace, manufacturing, chemical, or in my experience, mobility, this simple molecule can do it all. This jack of all trade ability does not mean that it is the only source of energy we will use. Just like an electric vehicle [EV], it has use cases that suit it perfectly and which do not.

Building on this, one trend I would like to describe in this article is one I have seen for years in the mobility space, specifically in transit / public transport. We all have electrical outlets in our homes and offices, but when it comes to charging a massive battery within the same time as a diesel fueling event, the cost of the installation is only one of your major problems. How will the electrical utility supply this? How will you guarantee that the power at night (the usual time when transits fuel their fleet) will be renewable? These two issues (a small part of a whole list of considerations for EV Bus upgrades) have led many larger transits to switch to hydrogen.

Just like EV buses, this fuel source has its challenges. The fuel is not always 100% renewable, and cheaper options are usually made from fossil fuel sources. Renewable options, as of now, have a higher cost. The molecule (H2) has a high energy density per unit mass but not volume. This forces Benjamin Traskunov Whether you think CNG, EV, internal combustion, or FCEV will dominate our world, think as an engineer whose many tools can address some problems better than others (pun intended) the station operators to pressurize the gas to 350 bar (standard pressure for larger vehicles) or seven hundred bar(standard pressure for light duty vehicles). In addition, cryogenic hydrogen (only a few degrees Celsius above absolute zero) can be used to further increase the energy density per unit volume.This requires temperature control and specific materials, which can further increase the cost.

"Whether you think CNG, EV, internal combustion, or FCEV will dominate our world, think as an engineer whose many tools can address some problems better than others"

Still, with all this said, gaseous and predominantly liquid (cryogenically cooled gas) hydrogen is becoming the favorite for many transits in California and across the world. A fueling experience for a gaseous or liquid station is identical if not faster than some diesel or compressed natural gas (CNG) fueling stations. Everything in the station is automated, and the energy source purchasing/handling experience fits well within many transits schedule and understanding. This has led many transit operators with one hundred buses and more, to seriously consider hydrogen over electric vehicles as the new upgrade for their aging fleet.

With all this said, even as a big believer in hydrogen, I will not claim that it should be the only fuel source for our vehicles (land, sea, or air). Each of these categories can benefit from a molecule that, at the tailpipe, has no harmful emission and, even at the source can have a net-zero carbon footprint. In a way, these fuel cell electric vehicles [FCEV] (hydrogen-powered cars) are also EVs. The hydrogen reacts with oxygen in the air and sends a current through a battery (which then powers a motor). Whether you think CNG, EV, internal combustion, or FCEV will dominate our world, think as an engineer whose many tools can address some problems better than others. We are working towards a brighter future one step at a time, and each step should be decided on a case-by-case basis, not a one-fits all approach.