Energy bills

[MrLongbeard]

They've probably replaced all the mains that had yarn stuffed in the joints that you had to keep moist by fogging glycol into the gas stream and replaced all the low pressure stuff with plastic pipe but there are still leakage issues. Some interesting technical issues probably arise out of pressurising it to 1000psi and shoving it around the transmission system but I suppose if you can do it with methane...

There's a stretch of road*, about 1/2 a mile long between my house at the in laws place that always smell of leaking gas, it's been that way for over 12 years, every couple of years they close the road and dig it up trying to fix the leak, but it still persists.

*said road is in the middle of nowhere, no other possible cause except leaking gas.

[Dodgy69]

Green energy is all a pipe dream. We have X amount of oil and water and when it's gone, we're gone. What you reckon.

[Yorick]

Green energy is all a pipe dream. We have X amount of oil and water and when it's gone, we're gone. What you reckon.

Yeah. We're short of water. Are you on drugs?

[Horse]

Green energy is all a pipe dream. We have X amount of oil and water and when it's gone, we're gone. What you reckon.

Yeah. We're short of water. Are you on drugs?

There's the itony: rising sea levels and water shortages, both due to global warming.

[Count Steer]

They've probably replaced all the mains that had yarn stuffed in the joints that you had to keep moist by fogging glycol into the gas stream and replaced all the low pressure stuff with plastic pipe but there are still leakage issues. Some interesting technical issues probably arise out of pressurising it to 1000psi and shoving it around the transmission system but I suppose if you can do it with methane...

There's a stretch of road*, about 1/2 a mile long between my house at the in laws place that always smell of leaking gas, it's been that way for over 12 years, every couple of years they close the road and dig it up trying to fix the leak, but it still persists.

*said road is in the middle of nowhere, no other possible cause except leaking gas.

Yeah. I was probably optimistic about the mains replacement programme. They probably keep trying quick fixes with minimum excavation on a lot of old gas pipework just to do the minimum until it does get replaced. One of the fixes is (or was) to drill a little hole in the outer of the joint and pump a sort of flexible glue* into it. It's a bit hit and miss. If it didn't work or the joint moved again after they buried it and leaked again they'd dig it up, drill another little hole and squirt more glue in. If that didn't work they'd dig it up again, clamp a bag round the joint and fill that with a sort of rubbery black stuff. If it was in a residential area they'd probably be more thorough.

* originally a formulation of Loctite 'cos it sets in the absence of oxygen.

[demographic]

This video covers a fair bit about hydrogen for heating buildings including some about why several governments have concluded its not a good idea. Old leaky pipes and hydrogen having small molecules, hydrogen embrittlement of metals, and when stochiometric (sp?) the way it detonates when lit.
In fact the blokes channel is well worth a watch as well, there's a lot to go at.



As a way to store energy however? Much better idea.

[Mr. Dazzle]

As above, the thing about Hydrogen is you need to make it. Long term thats pretty much guaranteed to involve renewable electricity and water.

So the thing is, if you've got enough renewable electricity to make all that Hydrogen, why wouldn't you just power things directly with said leccy instead and cut out a few middle men?

That's why I think Hydrogen is only going to be an interim or niche solution. Something a little bit like heating oil, some applications still use it but most don't.

[Horse]

So the thing is, if you've got enough renewable electricity to make all that Hydrogen, why wouldn't you just power things directly with said leccy instead and cut out a few middle men?

Distribution network for gas - albeit leaky - is in place. Less in-home infrastructure change required.

Distribution network for electricity, particularly in older homes, may not be sufficient for substantial additional load.

Some EVs (commercial vehicles, anything in potential 24hr use eg police) may need the quicker recharge capability of H.

Those are all guesses BTW

[Mr. Dazzle]

Yeah I think Hydrogen will be around for reasonably niche stuff, like I said.

It's inevitably gonna be more expensive though if you're using electricity to make it. Making hydrogen with electricity and water introducse a bunch of efficiency losses (quite big ones I'd guess), then you have to physically move something in tanks, pipes etc. which uses more energy, then there are even more efficiency losses (higher than those associated with electrical devices) when you burn it to do the useful work you actually want to do.

As a way of moving energy about, which is what you're actually doing here, it's always gonna have loads more losses than 'pure' electricity and hence will end up costing more. Which is why I say it'll be niche, used in either applications where you can't use electricity because of infrastructure or similar limitations, or where it's cheaper in the interim - converting old stuff, rather than building new.

[slowsider]

Use it to store the excess renewable energy, then burn to generate during periods of high demand. Like a gaseous Dinorwig.

[Mussels]

Yeah I think Hydrogen will be around for reasonably niche stuff, like I said.

It's inevitably gonna be more expensive though if you're using electricity to make it. Making hydrogen with electricity and water introducse a bunch of efficiency losses (quite big ones I'd guess), then you have to physically move something in tanks, pipes etc. which uses more energy, then there are even more efficiency losses (higher than those associated with electrical devices) when you burn it to do the useful work you actually want to do.

As a way of moving energy about, which is what you're actually doing here, it's always gonna have loads more losses than 'pure' electricity and hence will end up costing more. Which is why I say it'll be niche, used in either applications where you can't use electricity because of infrastructure or similar limitations, or where it's cheaper in the interim - converting old stuff, rather than building new.

Storing electrical energy is what we seem to be lacking, are there any alternatives to standard batteries that are also fairly inefficient and expensive?

[Mr. Dazzle]

There are a few in the works right.

Pumped water is the obvious but has huge up front cost of course. Cryogenic air seems to be gaining traction. Hot sand too, apparently that's really good. Loads of ideas, need to throw some shit and see what sticks.

Shit loads can be done just by spreading out demand, that would seem like the other obvious avenue. That's mostly gonna come down to variable pricing IMO.

[Kneerly Down]

It's inevitably gonna be more expensive though if you're using electricity to make it. Making hydrogen with electricity and water introducse a bunch of efficiency losses (quite big ones I'd guess), then you have to physically move something in tanks, pipes etc. which uses more energy, then there are even more efficiency losses (higher than those associated with electrical devices) when you burn it to do the useful work you actually want to do.

As a way of moving energy about, which is what you're actually doing here, it's always gonna have loads more losses than 'pure' electricity and hence will end up costing more. Which is why I say it'll be niche, used in either applications where you can't use electricity because of infrastructure or similar limitations, or where it's cheaper in the interim - converting old stuff, rather than building new.

It takes about 4kWh to produce c.3kWh of electricity -> hydrogen equivalent energy.
There's then the efficiency of making use of that energy.
Hydrogen fuel cells are efficient but very expensive. Gas turbine electricity generators are fairly cheap but not all that efficient although for elec with CHP it can be over 90% efficient...if you can use both the electric and the heat.

I think storage is going to be absolutely crucial, and massive.
We're talking about having 50GW offshore wind, 24GW nuke, 70GW solar and there's already 14GW of onshore wind.
Current [sic] UK demand is around 30GW.
Even with smart grids there's going to be some pretty big differences between supply and demand, both ways and seeing as we're not having a nice switch it off or on CCGT (or maybe we will for the real dark/still days) we'll need somewhere/something to pump all that power into.
Unless batteries really do have a massive leap of tech, probably hydrogen electrolysis is going to be a pretty big part of that.

As for pumping water, planning permission has already been granted to spend probably over £1bn putting a 4th wall around a local corrie.

That's only 1.5GW though.

[Mussels]

And storage is not as simple as smoothing out supply peaks each day, we may need to store enough for several days or more of the weather not behaving.

[Mr. Dazzle]

And play nicely with our neighbours.

[Mr. Dazzle]

It takes about 4kWh to produce c.3kWh of electricity -> hydrogen equivalent energy.

Just out of curiosity, is that "at plug", "at source" or somewhere in between or what?

[Kneerly Down]

Just out of curiosity, is that "at plug", "at source" or somewhere in between or what?

Current ( ) electrolysers might take 48kWh of electric to produce a kg of hydrogen from water.
The kg of hydrogen has 39.4kWh (HHV) / 33.6kWh (LHV) energy.

Haven't looked at it recently, but IIRC commercial fuel cells are running c.50% efficient, maybe c.85% if the generated heat is captured/used.
Not sure if the 48kWh includes compressing the produced gas up to storage pressure.

[Mr. Dazzle]

So really it's sorta 40-70% efficient over all...which is still better than some things!

Pumped water is ~75% right?

I've heard claims cryogenic air can be up to 90%, which makes me think its actually about 45%

[Kneerly Down]

So really it's sorta 40-70% efficient over all...which is still better than some things!

Upper end of that is if you can use the heat.
Might be tricky, given that we're talking about pretty much necessarily intermittent generation.

Pumped water is ~75% right?

Hopefully a bit higher. The Coire Glas project is reckoned to be 80%...not sure if that includes the impact of getting rid of the current 2MW hydro generator that is part of the plan.

I've heard claims cryogenic air can be up to 90%, which makes me think its actually about 45%

Will it be ready in the same 20yr timeframe as nuclear fusion power?

[Mussels]

I don't think efficiency is all that critical, it will save money but as long as we can supply electricity year round from green sources then the goal is reached.
After that people will find ways to increase efficiency, that will include using less as well as transmission losses.

Until it is discovered that slowing the wind down is causing climate change and compressors are melting snow.