Hydrogen has been in the news a lot lately, with big plans for Australia to become a green hydrogen superpower, converting renewable energy into hydrogen and sending it overseas to earn big export dollars.
There’s also a lot of talk about the potential of hydrogen as a fuel source for planes, trains, ships, and automobiles. If it moves, hydrogen can apparently move it.
Green hydrogen is a vastly cleaner fuel than the fossil fuels we’re familiar with. When you use hydrogen in a fuel cell vehicle the only thing coming out of that tailpipe is water vapour, so the attraction is obvious.
While it undoubtedly has a future as a fuel in planes, trains, and ships, it’s hard to see it having one in cars.
The first thing that needs to be understood about hydrogen is that it’s not so much an energy source, as an energy store. It converts energy that’s already in one form – electricity or natural gas – and converts it into another one – hydrogen, that can then be stored and transported.
Transport – that’s one of the reasons why hydrogen in hydrogen fuel cell vehicles has some big barriers to overcome.
While it’s relatively easy to install electric vehicle recharging stations, electricity is everywhere after all, creating hydrogen filling stations is anything but easy.
For starters hydrogen needs to be cooled to -253°C, and that requires a lot of sophisticated and expensive equipment.
Creating expensive hydrogen filling stations that can deal with that problem, for the tiny number of hydrogen fuel cell vehicles on the road, is a chicken-or-the-egg conundrum that dwarfs that of electric vehicles and their recharging stations. It’s hard to see how that hurdle will be easily overcome.
There’s more of a case to be made for hydrogen fuel-cell trucks that could use fewer, more centralized refueling depots, for example, if hydrogen storage facilities were also in place at a large delivery depot on a fixed route.
However, regardless of the logistical issues, hydrogen fuel cell vehicles just don’t make much sense from an engineering efficiency perspective.
They’re really just electric vehicles with an added layer of complexity that allows them to make their own electricity from hydrogen fuel. For now at least that makes them inherently more expensive than a battery powered electric vehicle.
Consider this best-case scenario: Solar panels or wind turbines produce electrical energy that is converted into hydrogen, losing energy in the conversion process.
The hydrogen is cooled and/or pressurized using more energy in the process. It’s then transported, using even more energy.
When it finally reaches the vehicle, it’s used in a fuel cell to perform a chemical reaction in order to generate electricity to power the motor in order to move the vehicle. That part at least is very energy efficient.
Compare that to a battery powered electric vehicle where you can simply plug into your home, charge up the battery and then drive.
That is very straight-forward and energy efficient, and electricity, unlike hydrogen, is everywhere.
So is hydrogen the fuel source for tomorrow’s cars? Well maybe, but it’s hard to make a case for it right now.