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Of course the issue with anything involving adding carbon molecules means they have to come from somewhere and will typically end up in the atmosphere.
That makes me nervous.
 

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Take the carbon atoms from this massive buildup of CO2 in the atmosphere, or seawater where a lot of it actually goes.
 

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Go the whole hog, then, and polymerise it into >C8H18. Then everyone can be happy.
Much higher carbon-to-hydrogen ratio, and less efficient. I think those of us here can agree that batteries look like the best (and most efficient) energy storage medium for personal transport. CH4 is more appropriate for longer term energy storage.
 

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Much higher carbon-to-hydrogen ratio, and less efficient. I think those of us here can agree that batteries look like the best (and most efficient) energy storage medium for personal transport. CH4 is more appropriate for longer term energy storage.
Sorry, you are stuck in the thinking-of-today.

If hydrogen is stored as as liquid alkane and burned at power stations using a CO2 closed cycle, all the carbon can be captured and then piped to a hydrogen manufacturing facility and used in that concentrated form to remanufacture the alkane of choice from renewable energy.

Octane represents just about the highest energy content by mass and has good volatility for complete combustion but is a modest and easily managed volatility.
 

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Sorry, you are stuck in the thinking-of-today.

If hydrogen is stored as as liquid alkane and burned at power stations using a CO2 closed cycle, all the carbon can be captured and then piped to a hydrogen manufacturing facility and used in that concentrated form to remanufacture the alkane of choice from renewable energy.

Octane represents just about the highest energy content by mass and has good volatility for complete combustion but is a modest and easily managed volatility.
I'd be interested to see how the energy efficiency numbers compare. It's a neat idea.
However, I was proposing sticking to CH4 in the short-to-medium term because we already have lots of equipment set up to run on CH4. Such as all those CCGT power stations we'd like to stop making so much use of - and millions of domestic gas boilers.
 

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They are £65,000. Let us know if you buy one. I think most of them are leased to "qualified" customers with access to government or EU funding..

Hydrogen-Powered Toyota Mirai | Toyota UK



You can get a Model 3 Long Range for a lot less money. The LR has about 350 miles of range.
Aach that’s too expensive, I’ll stick to ICE until they come down in price.
 

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I'd be interested to see how the energy efficiency numbers compare. It's a neat idea.
However, I was proposing sticking to CH4 in the short-to-medium term because we already have lots of equipment set up to run on CH4. Such as all those CCGT power stations we'd like to stop making so much use of - and millions of domestic gas boilers.
I was thinking of the Allam cycle to capture CO2 for alkane synthesis. After that, it is 100% efficient if it is all driven by renewable power with nowhere to go!
 

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I was thinking of the Allam cycle to capture CO2 for alkane synthesis. After that, it is 100% efficient if it is all driven by renewable power with nowhere to go!
That's a little disingenuous. If your TWh of "excess" renewables can be used to make CH4 that then allows you to generate 300GWh of electricity a few months later, that's better than "only" being able to generate 250GWh from your "Octane", say. So the efficiency does matter, even if you're dealing with "free"/excess power.
 

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That's a little disingenuous. If your TWh of "excess" renewables can be used to make CH4 that then allows you to generate 300GWh of electricity a few months later, that's better than "only" being able to generate 250GWh from your "Octane", say. So the efficiency does matter, even if you're dealing with "free"/excess power.
I wouldn't say 'disingenuous', but I understand your point.

The thing is that it has to be balanced with cost and other impacts such as size, ease of storage, safety, transportability, etc.. You might get a bit more out of it by soaking it up with platinum nuggets, but if it means the net cost is £2,000/kWh then efficiency is no longer the primary attribute, and storing CH4 probably falls into that. How will we store it? Pressurised? How much energy does that take? See what I mean .. or we can rebuild the big old gas storage towers .. how much effort will that take?

And the benefit is that if we are still pulling carbon in from other sources then maybe it is OK to 'decant' a bit of this octane stuff for direct use in 'legacy' motor vehicles?
 

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The thing is that it has to be balanced with cost and other impacts such as size, ease of storage, safety, transportability, etc.
Indeed. I think in reality we are pretty much in agreement. It's down to cost and ease or difficulty of storage and use. What I'm fairly sure of is that hydrocarbons are likely to be cheaper and more easily dealt with than Hydrogen!
 

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Our planet's biota has had billions of years of absorbing solar energy, and nature has had billions of years of storing it. What did they come up with? Hydrocarbons.

The giveaway clue to what is the best means of storage is the total absence on this planet of 'hydrogen wells'.
 

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By that logic, you’d think the best way of storing energy was molten magma. There’s way more of that inside the Earth.
 

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By that logic, you’d think the best way of storing energy was molten magma. There’s way more of that inside the Earth.
Yes, it is a brilliant way to store short term nuclear power output within the core, you are correct.

Now build me a mine to get the stuff out.

We have designs like that here on the surface, storing short term nuclear core energy in molten salt.
 

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Sorry, Mother Nature doesn’t want you to have it. That’s why it’s well hidden away. ;)
Agreed. Meanwhile, it left hydrocarbon oil lying around all across the planet's surface to collect in buckets!
 

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This thread drift quoting what forms of energy storage "Mother Nature" intended us to have access to, makes me think we may need to invoke the God Particle in our quest for energy storage after all...
 
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