I’m thinking of the coming time to replace vehicles and moving away from ICE. FCEV looks like a reasonable compromise between range/ pollution.
Has anyone gone this way? Is it liveable with? Is there sufficient UK & European infrastructure to make it a reasonable alternative. Not so interested in pure EV as I don’t really drive around town but longer distances, and I can’t see the point of duplicating drivetrain with hybrid/ mild hybrid (which I see as a short term solution which has to many compromises).

By coincidence VW announced today that they are diverting resources away from fuel cell development to focus on BEV

Pretty scathing judgement on hydrogen in Sustainable Energy – without the hot air.

I started reading that Sustainable Energy post. I got as far as this before I couldn’t take it seriously any more:

The problem is
that compressing the air generates heat that’s unlikely to be used efficiently;
and expanding the air generates cold, another by-product that is unlikely
to be used efficiently.

Compressing and expanding a gas moves heat around (hence the term “heat pump”). It doesn’t “generate cold” because cold is the absence of heat, so it can’t be generated. The expanding gas absorbs heat from its surroundings, so it cools the surroundings. It doesn’t “generate cold”.

Compressing the gas does release heat (rather than “generating” it). This could be used for other purposes such as heating buildings, etc., but that’s missing the bigger point. The key issues will be whether the overall output of the compressed air engine are large enough in comparison to the energy needed to compress the fluid (i.e. the thermal efficiency) to be better than a conventional battery, and what the energy density of the system will be (i.e. how large of a tank would you need for a useful range).

Again this is never going to be any sort of solution. Its pure greenwash. Yes you get no tailpipe emissions but you still have the issues of emissions from the generators and Hydrogen is very difficult to store and transport. Plus there is the inbuilt inefficiency in taking electricity, making it into hydrogen, making the hydrogen liquid. Plus the rare and highly polluting to mine elements in the catalysts in the fuel cells.

Someone will know the number but if you end up with half the energy that you generated in usable liquid hydrogen for I would be surprised. Everytime you change energy from one form to another you get losses. FCEV you go – Kinetic energy to electrical to chemical ( then compress the gas or cool it) then to electricity then to kinetic. Losses at every step.

The only answer is to drive less in smaller lighter vehicles with higher occupancy. anything else does not reduce the problem but merely moves it.

Industrial hydrogen is produced from natural gas, not by electrolysis.

OK Even worse from the environmental penalty point of view then 🙂

@hols2

I started reading that Sustainable Energy post. I got as far as this before I couldn’t take it seriously any more

It’s not a post, it’s a book, and the (deceased) author was a Professor of Engineering at Cambridge University so probably knows more than you or I about thermodynamics – https://en.wikipedia.org/wiki/David_J._C._MacKay.

His book’s shit though.

Compressing the gas does release heat (rather than “generating” it).

What’s your understanding of the word ‘generate’ then? I think it means something different to ‘create’ which is the inference you appear to be objecting to. An electricity generator doesn’t ‘make’ electricity from nothing, it converts chemical energy into kinetic energy into electrical potential energy. Strikes me that the word ‘generate’ kinda works in the learned professor’s context?

I think your argument has more merit when it comes to ‘generating cold’ as cold is an absence of heat, but it’s a little pedantic 😏

Proton exchange membrane Fuel cells generally operate at around 50% efficiency. If the hydrogen is generated from electrolysis from renewable sources and compressed using the same energy source bthen they are better in terms of emissions than cars. But that’s generally not the case, hydrogen is a by product of more polluting industrial processes.

In vehicles the hydrogen is generally in a pressurised tank at 700 bar. Not in liquid form.

The catalyst is platinum and that’s recoverable and can be recycled from old fuel cells. The problem is life, degradation rates of the fuel cells means that I’m not sure you’ll get the life span you’d expect from such an expensive vehicle.

@supersessions9-2
Thanks for that. My mild assumptions are that offshore wind turbines could be used to generate and compress hydrogen which would make it a relatively low impact fuel. Particularly if that generation happens during low demand periods when those turbines aren’t required to meet grid demands.
But if their lifespan isn’t so good then that’d be a real problem. By short lifespan what are you think of?

Just looking at the Toyota mirai and they are giving it a 100k mile warranty which is better than I expected.

I’ve not worked in the industry for a couple of years but the technology I worked with would not have done that.

The way around cell degradation is to put more in and that obviously costs more.

It’s a real chicken and egg situation with fc vehicles. There won’t be the uptake without the infrastructure of filing stations but not company is going to invest in infrastructure without the customer uptake.

I worked in the industry for five years and am unconvinced it’s the right answer for cleaner vehicles.

It’s a dead end for passenger cars IMO. I think it has potential in commercial applications if you’re big enough to have your own H2 station. Cars it’s really just the likes of Toyota and Honda who are being very Japanese about it, and companies soaking up EU grant money while they can.

Long distance EV travel is child’s play compared to hydrogen – there’s only a handful of commercial H2 stations (mostly around London) plus some universities with them. Access, billing, training(!) requirements vary. Costs are worse than an ICE car. And of course you can only get H2 in these places – absolute worst case you can plug an EV into a 13A socket and fill it slowly.