[thadjo]

I'm seeing a lot of people here assuming that the purpose of green hydrogen is for fuel cells / automotive transport, but I don't see many people in this space talking about that anymore (except Toyota).

Instead there is a lot more interest in using green hydrogen for industrial purposes or as a key building block for cleaner fuels like methanol. Currently green hydrogen is expensive to make and sucks to transport. But it will likely get a lot cheaper to produce in the next 10 years and you can convert it into fuels that are easier to transport.

There is recent episode of Volts that interviews a startup trying to do this: https://www.volts.wtf/p/making-shipping-fuel-with-off-grid#d...

[mustafa_pasi]

I agree with this. I think there will still be niche products using liquid fuels. Like for example "explorer" or "offroader" type vehicles that require higher energy densities. And aviation of course. But commuter transportation will be using direct current or batteries.

But the two chief uses will be in industrial processes that use hydrogen directly, in chemical processes that use hydrocarbons directly, and in energy storage applications where you need to store large quantities of energy for weeks or months or years.

[RetroTechie]

> I think there will still be niche products using liquid fuels.

One of those niches: boats. Specifically: user-owned recreational ones.

Not because it's hard to build electric propulsion systems for boats. There already exist many types of motors, batteries & control systems to choose from. Not because battery weight / size is a problem (it isn't). Not because of safety issues (gas/diesel have their own).

But because it requires a big upfront investment. Converting to electrical propulsion is (for most boats) expensive. For someone who already owns a gas/diesel powered boat, but not the $$ to convert into all-electric, that's a big hurdle.

Of course new boats will replace old ones over time. But average boat lasts much longer (read: takes much longer to replace) than eg. cars. Average car is what, 6..8y old? Average boat more like 20y+. Electric conversion that's both easy and cheap, is not a thing (yet?).

Professional owners like ferries, commercial shipping or boat rental, will deal with this. Private owners of recreational boats, not so quick.

That means: there will be gas/diesel powered boats around for many years. Having 'green' fuel for those available everywhere, would be quite a boon.

[micv]

There's been talk of replacing the natural gas used directly for heating in the UK with hydrogen. I have absolutely no idea how viable that will actually prove to be but it seems difficult.

[sbradford26]

So technically it might be possible to do that. But I don't think the economics would work out for that. Mostly because your cost of hydrogen will then be linked to the cost of electricity coming in. Given the choice between hydrogen which will cost the base electricity prices + overhead of electrolysis plants and transportation or to just use a resistive heater, you would most likely pick the resistive heater since it would be cheaper.

Not saying people should switch to resistive heaters since they significantly less efficient than heat pumps but simply that resistive electric heating would be cheaper than hydrogen (If that hydrogen is produced using electrolysis).

[pjc50]

> base electricity prices + overhead of electrolysis plants and transportation

IF the capital cost of electrolysis isn't too bad - and this paper suggests that it can be done more cheaply than the current use of platinum - then it's economical to run them with zero or negative cost electricity produced by renewables overbuild, then keep the hydrogen in tanks (another if) or convert it to actual natural gas via the sabatier reaction and keep that. That may be cheaper than building really huge battery farms for long-duration electric storage.

[sbradford26]

So negative cost electricity tends to be a side effect of large thermal power plants that can't ramp down quickly due to a drop in demand. Renewables can typically be turned off relatively easily. Maybe there will be situations that might still happen with an over build of renewables but I haven't heard of any. But either way if prices of electricity become very cheap then using that electricity directly with a heat pump or resistive heater also becomes cheaper.

I am not saying making hydrogen can't be economical utilizing cheap off peak rates. I just don't see it as economical for home heating or typical consumer transportation since there are alternatives that utilize electricity directly.

[bushbaba]

Or as an renewables energy storage for use in leaker plants.

[jfengel]

Peaker plants. But the slip is nicely Freudian: hydrogen is incredibly hard to contain, and an awful lot of it does leak out.