this post was submitted on 25 Apr 2024
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Discussion of climate, how it is changing, activism around that, the politics, and the energy systems change we need in order to stabilize things.

As a starting point, the burning of fossil fuels, and to a lesser extent deforestation and release of methane are responsible for the warming in recent decades: Graph of temperature as observed with significant warming, and simulated without added greenhouse gases and other anthropogentic changes, which shows no significant warming

How much each change to the atmosphere has warmed the world: IPCC AR6 Figure 2 - Thee bar charts: first chart: how much each gas has warmed the world.  About 1C of total warming.  Second chart:  about 1.5C of total warming from well-mixed greenhouse gases, offset by 0.4C of cooling from aerosols and negligible influence from changes to solar output, volcanoes, and internal variability.  Third chart: about 1.25C of warming from CO2, 0.5C from methane, and a bunch more in small quantities from other gases.  About 0.5C of cooling with large error bars from SO2.

Recommended actions to cut greenhouse gas emissions in the near future:

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[–] Nebulizer 7 points 7 months ago* (last edited 7 months ago) (2 children)

Oh neat, I actually know a lot about hydrogen-natural gas blends!

I read the report because of this claim:

And now, a team of British researchers has found adding hydrogen to natural gas actually increases how much natural gas leaks from stove burners and boilers because the smaller hydrogen molecules help the larger methane ones escape.

I've never heard of small hydrogen molecules helping larger molecules leak. I was curious what the mechanism for this was. It turns out the report does not make that claim at all. In fact, the report claims the additional leakage from hydrogen blends is most likely just the hydrogen leaking. I didn't run the numbers myself but the data presented seems approximately aligned with that. Hydrogen leaking through fittings is already a well-known and established challenge of blending hydrogen with natural gas. So the central thesis of this news article is completely fabricated.

I am a little surprised the utility companies are going to soon be mixing in hydrogen. I didn't think we we're quite ready to blend in hydrogen into natural gas for the leakage reason, and also because of production scaling issues that we haven't resolved yet. These challenges are likely within reach soon. For example, the United States department of energy has a large research initiative right now to help lower the cost of hydrogen production to be more competitive with natural gas. We also need to make sure that hydrogen is produced in a carbon-free or carbon neutral way, which is probably going to be dependent upon our electrical grid becoming carbon free.

[–] Nebulizer 3 points 7 months ago* (last edited 7 months ago) (1 children)

Also, I think we need to be moving towards 100% hydrogen if we want to use combustion as a green replacement for natural gas. However, I don't think many of the appliances that currently use natural gas could safely use 100% hydrogen because of the properties of hydrogen gas. Primarily, I think the flame speed of hydrogen would require us to redesign the various combustors that use natural gas currently so that we don't have flashbacks. Additionally, the hotter burning of hydrogen might cause material failure issues in our current natural gas burners. The research I've done is shown that we could probably get away with 30 to 40% hydrogen, maybe dependent on the exact burner. I don't think moving to 100% hydrogen is feasible without a massive replacement of all of our gas burning appliances.

[–] Nebulizer 2 points 7 months ago

One more thing. Running hydrogen, even in blends of 30% hydrogen/70% natural gas, creates a large amount of extra NOx production. NOx, of course, is a pretty nasty pollutant. We need to redesign our current natural gas burners to help control NOx at high hydrogen blends.

[–] [email protected] 2 points 7 months ago

They're not ready to do it except in limited-scale demonstration projects — they're promoting the idea of a transition to hydrogen as a means of creating social permission to keep on burning the largely-methane gas that has been pumped through the pipes for decades.