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Comment by londons_explore | Hacker News Reader

You know what does make it make sense?

If you can take natural gas out of the ground, split it into hydrogen and CO2 (releasing heat, which can be used to generate electricity), and inject the CO2 back underground to help release more oil and gas.

At this point, you have hydrogen gas.

Sure, you could burn that hydrogen to make more electricity, but it works out financially better if you can directly use it.

The benefit of this approach is it can make use of most of the existing oil and gas infrastructure, and countries sitting on big gas reserves have a use for them.

The downside is it makes minimal sense unless there is some financial disincentive from just burning the gas and releasing the CO2.

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Unfortunately it is a bit tricky in practice, and still have a very significant global warming footprint[0]. You're never going to capture 100% of the CO4, and oil and gas wells tend to leak quite a lot of methane to the atmosphere.

So-called "blue" hydrogen only results in about 10% less GHG emissions than traditional "grey" hydrogen. It's something, but not big enough of a difference to actually be usable.

[0]: https://onlinelibrary.wiley.com/doi/full/10.1002/ese3.956

You hit the nail on the head, this is why oil companies are pro-hydrogen.

They can greenwash their natural gas into "green" hydrogen and get even more profits. H2 prices are at least 5-10x compared to natural gas.

Isn’t that effectively what they call “blue hydrogen”[0]? All oil companies seem very slow in deploying that; there is no question that it is much more expensive than just releasing the CO₂ in the air.

[0]: https://corporate.exxonmobil.com/what-we-do/delivering-indus...

I think oil+gas companies are currently just waiting for the right moment to deploy it.

Blue hydrogen only makes sense with global carbon caps, taxes or quotas. And it only makes sense if CO2 injected underground doesn't count towards that cap/tax/quota.

So far, there is no political appetite for global taxes/caps/quotas, so blue hydrogen is only at pilot-plant scale.

This is similar to fracking, no? Doesn't it have the same seismic/water table problems?

Yep. And it won’t be 100% efficient. The energy to capture and store the co2 is likely greater then the energy you get in hydrogen

CO2 reduces the viscosity of oil, and helps get more oil out of the oil well.

Even ignoring climate benefits, it's still worth pumping CO2 down the well for financial reasons alone - especially towards the end of the lifespan of classical oil wells.

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