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Comment by mikeatlas | Hacker News Reader

Their claim is that this method is still yet cheaper than drilling/fracking.

> Their claim is that this method is still yet cheaper than drilling/fracking.

They claim the green way to go is converting hydrogen into methane....check out the link for a company claiming the green way to go is converting methane to hydrogen:

https://www.pnnl.gov/news-media/new-clean-energy-process-con...

I rather suspect that taking an energy detour through methane either way is a red herring. I mean....the OP says that their whole process is powered by solar energy. So they are presupposing that solar energy is going to be WAAAYYYY cheaper than methane. Why not just use the solar power directly?

The cost of natural gas on the Henry Hub is somewhere around $300/ton. A ton of natural gas requires 2.75 tons of CO2, so the cost of CO2 capture has to be well below $110/ton (and that ignores the cost of the hydrogen and the equipment for doing the methane synthesis.)

They must be assuming large increases in natural gas prices or large CO2 taxes.

I think it will be much easier to get the price/BTU of H2 down below the current price of natural gas than it would be to get synthetic methane down that cheap.

(If they are assuming large CO2 taxes then it's probably a better business model to just collect CO2 from the air and sequester it.)

> so the cost of CO2 capture has to be well below $110/ton

they say $250/t in the article, but could you expand how you came to "A ton of natural gas requires 2.75 tons of CO2"? Where 1.75t of CO2 is disappearing in result?

Molecular weight of methane (CH4): 16

Molecular weight of CO2: 44

One molecule of CO2 is needed to get the carbon atom to make one molecule of methane.

44/16 = 2.75

The 1.75t of CO2 that went missing is the oxygen, which obviously isn't in the methane.

Thank you, I am an idiot in chemistry )

I went to double-check your math and I don't see $300/ton on Henry hub.. the units are a little weird as it looks like the price is per million btu which is... 50 pounds? of lng, so to get the per-ton price we take the Henry hub price and multiply by 40 (2000 pounds per ton divided by 50 pounds per million btu)? with a 52-week high of 3.63, this would get to $177 per ton, which seems short of your $300/ton? Anyway, I ask because id love to learn where I went wrong with the math (my result makes your point stronger, not contradicts it...)

I think you're closer to right. I started with a wrong figure that I didn't double check. Thanks for catching the error.

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