In June in Sydney, Energy Matters went to the Australian Energy Storage conference and spoke to Ian McLachlan who is Senior Low Emission Site Specialist at Toyota, and learned a lot about Hydrogen cars! It’s really fascinating.
What is a Hydrogen Fuel Cell vehicle (HFCV)?
Both EVs and HFCVs run from electric motors. It is where the electricity comes from which is the difference.
In the case of electric vehicles, electricity comes from the battery. With a hydrogen fuel cell vehicle, hydrogen gas is stripped of its electrons in the “fuel cell”, and those electrons are used to power the motor. A fuel cell is essentially a battery that uses gasses to produce electricity as opposed to solids or liquids as in regular batteries.
Contrary to popular opinion, the hydrogen is not burned with oxygen, and then the heat from the combustion used to power an engine. The water results from the stray hydrogen ions (the hydrogen atoms stripped of their electrons) combining with oxygen drawn in through the air intake.
Note that Toyota class their HFCVs as FCEVs (Fuel Cell Electric Vehicles), or sometimes as FCVs.
Do Hydrogen vehicles pollute?
No. HFCVs do not directly have any emissions. Air comes through an intake valve and only oxygen combines with the hydrogen to form water.
The Toyota Mirai FCEV creates about 40L of water from a 500km trip. This is not vented to the atmosphere but rather condenses and drips out of the vehicle similar to water extracted from air by automotive air conditioning systems.
Nitrogen also is in air, but no worries, there is no ammonia (NH3) output by the fuel cell!
Are Hydrogen cars better than Electric battery cars?
The chief downside of battery charged electric vehicles (EVs) is the long time required to charge the battery. Fast charge technology alos allegedly reduces the life time of the battery in charge cycles.
A hydrogen car on the other hand, only takes 3-5 minutes to fully refuel.
Safety of Hydrogen Cars
Hydrogen is non toxic. But like all gases, if it is in quantities that don’t allow sufficient oxygen to get to your lungs, then it is an asphyxiant. But you could say the same about Nitrogen, Helium, and lots of other common gases. Remember, Nitrogen makes up 70% of the air that we breathe.
The Hydrogen gas is stored under pressure in a tank in the vehicle. The picture below shows the three layers around the tank, so the possibility of rupture is low.
Keep in mind that hydrogen is the lightest element and with an atomic weight of close to 1, it’s going to make its way up and out of there really quickly. Contrast this to liquids and some of the heavier gases which may pool on the ground, providing fuel for any fire. Note that LPG (liquid petroleum gas) has been powering most taxis in Australia for over 30 years.
People often bring up the Hindenburg, which was a hydrogen-filled airship that exploded in a spectacular disaster in 1937. Some say that it wasn’t the hydrogen that was the primary fuel for the conflagration, but the aluminium skin of the zeppelin. Others point to carbon compounds in the same skin.
Also, some misunderstand HFCVs to be powered by liquid hydrogen. It is a gas when it is in your vehicle’s tank, so no super low temperatures are necessary. Liquid hydrogen is not necessarily even part of the cycle of manufacture to use. Hydrogen stations have a choice of having hydrogen delivered as a liquid or a gas, or even making their own hydrogen on site.
Sources of Hydrogen for cars
- Brown hydrogen – hydrogen taken from other organic compounds, such as coal or oil
- blue hydrogen extracted from natural gas. Most hydrogen sold today comes from natural gas reforming.
- and green hydrogen which comes from water.
Both brown and blue hydrogen leave you with a carbon residue from the hydrocarbon compounds used as input.
Green carbon, if the electricity comes from fossil fuels, also has carbon emissions.
It would be truely green if you can source electricity from renewables such as solar or wind. Then it truly is zero carbon.
Who supports Hydrogen for cars?
Players like Toyota, Hyundai and oil companies have formed an advocacy organisation for hydrogen powered mobility.
Toyota now characterize the company as a mobility company, not a car company. Their CEO has declared Hydrogen to be the future.
The Mirai is Toyota’s flagship Hydrogen vehicle. It’s available in Japan, Europe and the USA, especially California where the State Government is backing hydrogen infrastructure.
There is only one in Australia. It was pulled off the Japanese production line, so it is right hand drive.
Why not Hydrogen powered cars?
Understandably in any industry which is in danger of disruption, even one as young as the electric vehicle industry, there is some push back. Elon Musk of Tesla has referred to fuel cells as “fool cells”. He has also called them “mind-bogglingly stupid”. His conclusion is based on the inefficiency of electrolysing water and then pressurising the hydrogen, compared to just using solar panels to charge a battery.
Currently, as with EVs, lack of infrastructure and the consequent “range anxiety” is a concern for HFCVs. In Australia, owning one is not feasible because there are only two refueling stations in the country. One at Toyota in Melbourne and one at Hyundai in Sydney.