Home Interviews THMG131 – Hydrogen Vehicles and Filling Stations with Jen Hamilton

THMG131 – Hydrogen Vehicles and Filling Stations with Jen Hamilton

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In this episode, Bob and Mike talk to Jen Hamilton from the California Fuel Cell Partnership about hydrogen gas, cars, and filling stations.

Complete Show Notes

1:05 Introduction to Jen Hamilton

  • Expert in safety education and codes and standards management
  • Works at the California Fuel Cell Partnership

2:30 Adding Hydrogen Dispensing to Existing Gas Stations

  • Dispenser is a good distance away from the equipment itself, which can be costly
  • Underground tubing brings hydrogen out from storage and through the nozzle into the car
  • Interface is very similar to what we normally see when fueling at a gas station
  • California has been using this technology for 15-20 years
  • Getting to commercialization because real customers are leasing or buying hydrogen-powered vehicles
  • 12 stations coming to the East Coast between Boston & New York City
  • Toyota is already manufacturing hydrogen-powered vehicles and other brands are in the mix, too

5:05 Why Use Hydrogen Fuel Cell Vehicles?

  • Overall goal of the industry is reducing vehicle emissions – fuel cell vehicles are all zero emission
  • Advantages include:
    • Short refueling time – only takes a few minutes to fuel at the dispenser
    • Range is similar to what you get with a gasoline engine
    • Fuel cells can also be put into transit busses, which they’re already doing in California
    • Also used frequently in forklifts – power output is consistent from full to empty
    • Can also be small enough to power a laptop or cell phone or large enough to provide backup or emergency power – saved the day during Hurricane Katrina as a result

8:45 Hydrogen Fuel Cell Composition

  • Anode and cathode with a carbon-based membrane between them
  • Platinum is embedded in the membrane to catalyze the hydrogen molecule, which breaks down into protons and electrons
  • Electrons have to be routed to an external circuit to provide the electricity that powers the car
  • Protons pass through the membrane (proton exchange membrane) – on the other side of that reaction, the protons and electrons come together with oxygen from the air to create water (the tailpipe byproduct)
  • Very efficient system – heat is much lower than internal combustion engines
  • Solid state unit – vehicles use a non-conductive coolant to manage the temperature of the overall system
  • All of these vehicles also use a hybrid battery (i.e. lithium ion)
  • Energy is stored in the vehicle in the form of a compressed gas – can be stored indefinitely at pressure in Type 3 or Type 4 cylinders
  • Units are tested – virtually impenetrable and will not explode under any circumstances

12:10 At the Filling Station

  • Stations can have it shipped to them as gasses or liquids
  • Liquids have to be vaporized into gasses, compressed, and stored at pressure for cascade filling
  • Composite tanks are a must since it’s high-pressure ground storage

14:00 Hazards Associated with Storing and Transporting Hydrogen

  • Hydrogen is already being made and stored for other industrial purposes – NFPA 704 placarding used for storage and DOT placards used for trailers and tankers
  • Hydrogen is a cryogen, but it vaporizes quickly to a gas and wants to rise
  • It’s not the gas that’s a concern – it’s the pressure in the containers
  • However, there’s no liquid phase in gaseous storage like you have with a propane tank and no risk of BLEVE
  • All transport vehicles are equipped with venting and pressure relief – hydrogen can be vented to the atmosphere because it’s non-toxic

16:15 Things to Look for at Filling Stations

  • Orange high voltage cables – hybrid vehicle
  • Cylinders – pressurized gas
  • The letter “G” – could be hydrogen
  • Vehicles are badged with the make and model like any other commercial vehicle – most say “Fuel Cell,” which indicates they only use hydrogen

17:30 Handling Hydrogen Fires

  • Pressure relief devices aren’t standardized across different vehicles or identified on the car
  • Leaking hydrogen can’t go anywhere into the passenger compartment or where it might be trapped – up to automakers to figure out how to engineer this
  • TPRD (thermally-activated pressure relief device) is integrated into the steel end of the tank that regulates temperature and pressure
    • This is a diffusible metal plug that opens to release pressure – once it’s opened, you can’t close it
  • Car itself is highly unlikely to just catch on fire – any fire would probably be the result of an adjacent gasoline fire
  • Any venting will go towards the tanks themselves or towards the ground at a slight angle – you’ll find this at the rear of the car
  • Venting will be very loud since it’s a high-pressure vent – you’ll hear a loud pop or bang
  • You’ll see a pretty impressive hydrogen flame initially – this will hit the ground and spread out some distance from the car before going up
  • Flame gets smaller and smaller as it continues burning since the hydrogen is escaping and the tank is relatively small
  • Carbon-based flame remains since that’s what caused the venting in the first place – this packs a lot more heat due to the internal flame temperature
  • No way to know whether this has happened other than with eye witnesses since it usually happens before firefighters arrive at the scene
  • Understand that any fire will be coming from the rear of the car or the fuel door
  • In many cases, it’s smart to just let the hydrogen burn itself out and not try to cool off the tanks – in some cases, cooling causes the TPRD not to activate
  • If the leak is large enough, the vehicle shuts off the solenoids and goes to battery power so you can safely get off the road – won’t re-start after that so you can get it serviced
  • Car is constantly monitoring itself to keep these things from happening in the first place
  • Fueling stations can shut off hydrogen pumps if there’s any kind of issue

28:55 Contacting Jen and Learning More

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