Hacker News Reader

Comment by slothtrop | Hacker News Reader

As far as I'm aware, ammonia currently can only viably be created with fossil fuels as inputs, for the same reason blast furnaces to smelt steel requires fossil fuels. But to follow where I think you're going, I expect nuclear to be the next most viable

View on HN

Ammonia can be produced from any power source. So in theory we could use renewable power to manufacture "green ammonia" for farming. So far that has only been done in small demonstration projects and all the real fertilizer manufacturing is still done using fossil fuels as the main input.

https://e360.yale.edu/features/from-fertilizer-to-fuel-can-g...

The level of power required is so high that renewables are nowhere near viable at this point.

> for the same reason blast furnaces to smelt steel requires fossil fuels

https://www.hybritdevelopment.se/en/

We’re well on our way to fossil free steel.

As of yet nonexistent tech just supports my point.

It doesn't NEED natural gas as input, there are other ways, but natural gas as input is saving a massive amount of energy, possibly near 10x current energy input, by not having to split hydrogen from water. And fertilizer production is already one of the most energy intensive processes we have, so increasing that multiple times over is a huge amount of energy.

Basically hydrogen production is the limiting factor in producing clean ammonia from the air instead of using fossil fuels, and clean (and cheap) hydrogen production is far from a solved problem.

Ammonia is made with hydrogen. If you are making hydrogen, nuclear biggest putative advantage, its lack of intermittency, becomes much less important.

If you are proposing thermochemical watersplitting using nuclear heat to make hydrogen, there is very great reason to be skeptical of that approach (superheated vaporized sulfuric acid, anyone?). These processes have never been practical, and the decline in cost of renewable electricity, and the decline in cost of electrolyzers, makes the thermochemical approaches even less competitive.

Reply on news.ycombinator.com