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[deleted] t1_iwphd9w wrote

Reply to comment by filosoful in Overhyping hydrogen as a fuel risks endangering net-zero goals by filosoful

Hydrogen does get around one massive issue - infrastructure. A lot of Europe is heated by gas, and switching everyone over to heat pumps will cost tens of thousands per home. Mixing hydrogen with something inert to mimic the volumetric energy density of methane would allow you to switch over at the distribution end, with little effort/cost to the individual. Generating hydrogen via green sources then burning it again isn't the best way of heating a home, but it's a fantastic stopgap in the transition period that allows us to switch off the natural gas aspect of our fossil fuel usage sooner than we otherwise would.

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Popswizz t1_iwq2mkq wrote

Except it's not really, I was part of analysis on the subject and with current technology, even with free electricity (as this would be a mean to offset green energy uncontrolled output) there's no payback to pay for the machine before 10 years unless hydrogen is subsidized

And even then as you said you need a natural gas pipeline near that can accommodate high hydrogen % and natural gas heater in home that can as well which is a logistics nightmare

There's some very niche usage and the one you mention is one but it's far from a widespread technology we can use everywhere

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[deleted] t1_iwq95pj wrote

That's not really a niche usage, pretty much every home and cooker in Europe is powered by natural gas. It's not an economic suggestion by any means, it's a green one due to the speed it can be rolled out. It's far less of a logistical nightmare than replacing every boiler (of which a high percentage don't have the required hot water tanks, or the space to accommodate them) with heat pumps over the same time period. Do we even have enough heating engineers to change 200 million homes over in the few years it would take to replace methane with hydrogen at the distribution level?

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Popswizz t1_iwqq8at wrote

It's niche because not all pipeline are able to accommodate hydrogen in large quantity, because not all boiler can accommodate high percentage of hydrogen, because not all green energy powerplant is near enough a pipeline to link to it with their hydrogen production, so it's niche because logistical it's a nightmare not because it's not technically doable

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Tenrath t1_iwqdc4a wrote

I could be wrong, but I think there are also changes required at the consumption end to accommodate the change in gas. Same reasons why a propane boiler and natural gas boiler are not interchangeable without modification kits.

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[deleted] t1_iwqe6y7 wrote

There'd be small changes, yeah. I'm on the aircraft side of things, but assuming they're similar enough it'd be a component analogous to the flame holder that would be the main issue. There's a minimum hole size a flame can propagate through that depends on the gasses.

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danielv123 t1_iwq861g wrote

Hydrogen is one of the worst alternatives to heat pumps I could imagine, short of resistant heating powered by hydrogen driven turbines. Electrolysis is about 75% efficient. That means you need a lot of extra electricity. In addition you need facilities for electrolysis, which isn't cheap.

It might help a bit as a form of storage but is still worse than hydrogen + tubine + heatpump.

Cost to the individual shouldn't matter, the lowest overall cost should be picked. In a hydrogen conversion scenario the lowest cost often ends up being natural gas, which gets us nowhere.

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[deleted] t1_iwq8rfs wrote

It's a matter of inertia, not just cost. You will get people transitioning to heat pumps over time, absolutely, and they're the best option by far. But in the mean time, hydrogen gets those same people off natural gas incredibly quickly, without the gargantuan total-war-like effort required to replace every boiler and cooker in every home in Europe in the same time frame.

The overall cost isn't the only consideration. Stopping a large chunk of emissions quicker but expensively is better than too late and cheaply.

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