[umvi]

So basically: wind generators power electrolysis to create hydrogen, the hydrogen is fed to a normal Haber-Bosch plant which is still powered by coal or gas. So basically the wind power is just replacing the carbon footprint of a single input (hydrogen) to a H-B plant?

[philipkglass]

The only chemical inputs a Haber-Bosch plant needs are nitrogen and hydrogen. The nitrogen always comes from air and in this plant the hydrogen comes from electrolysis. The plant also needs electrical power to run compressors, but that can also be supplied by wind and it's minor compared to the embodied energy of the hydrogen input.

[hunterpayne]

Sort of, but there are important details you miss. First the nitrogen triple bond is one of the strongest in nature so it takes a lot of energy to break it. So we don't actually do that in the way you think in a real ammonia plant. Instead we heat (usually) Magnesium and that extracts Nitrogen from the air (actually a pure nitrogen atmosphere). That's not what is happening in this plant. And the difference in the effectiveness of those two different methods is probably pretty big. This seems more like a PR stunt to get investment.

[philipkglass]

The reaction N2 + 3 H2 => 2 NH3 is thermodynamically spontaneously but kinetically forbidden by the strength of the N-N bond. That's why the key breakthrough of the Haber-Bosch process is the use of a doped iron oxide (magnetite -- is that what you meant?) catalyst that allows the reaction to proceed at an industrially useful rate. This wind powered ammonia plant gets the hydrogen from water electrolysis instead of steam-reformed methane; the plant is otherwise using a conventional Haber-Bosch process.

Using electrolytic hydrogen to make ammonia was fairly common in the first half of the 20th century, because a lot of remote hydroelectric plants didn't immediately have uses for all of the electricity they could generate. They turned low cost electricity into pure hydrogen and used it to make ammonia and derivatives, which were easier-to-transport high value products.

[WJW]

Why would the HB plant be powered with fossil fuels? You can power that with wind power as well.

[ch4s3]

Typically the natural gas is the source of the hydrogen. Usually natural gas is burned to form steam to split more natural gas (CH4) into carbon and hydrogen. That’s traditionally cheaper than electrolysis.

[jimnotgym]

Unless your electricity is 'free', presumably?

[ch4s3]

Free has a habit of changing the economics. This is good news, decoupling ammonia from natural gas would make agriculture more resilient to Middle East disruptions.

[WJW]

TFA literally states "Wind energy powers the electrolysers that supply hydrogen to a Haber Bosch plant." First paragraph.

[kulahan]

It’s mot powered with fossil fuels. It uses fossil fuels as an ingredient.

[WJW]

No it doesn't. It electrolyses water and combines the resulting hydrogen with nitrogen from the air.

[kulahan]

Wrong. Natural gas is the most common catalyst, but plenty of plants use oil, coal, and other hydrocarbons.

A quick refresher: https://en.wikipedia.org/wiki/Haber_process#Process

[WJW]

Yes I know how the usual process works. The plant in the article is different, because it uses electrolysis to make hydrogen for the HB plant. You'd have known this if you'd read even the first paragraph of the article.

[kulahan]

Right, and if you read the first paragraph, you’d see it’s meant to increase and decrease power consumption based on demand.

How are they gonna turn up the damn wind, WJW? Is this a plant that shuts down every time there’s a calm day? Is it a plant for funsies or meant to be a reliable station? Either this is a gigantic art project, or it has hydrocarbon inputs for running on days when the wind is calm.