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A comment on 100% renewables doesn’t equal zero-carbon energy, and the difference is growing. Parent comment

Re:100% renewables doesn’t equal zero-carbon energy, and the... by AngryData on Sunday May 26, 2019 @12:04AM (#20013050)
Also fossil-fuel chemical reagents used for all sorts of material production.

And the big one, artificial fertilizer, which uses natural gas because the electrical equivalent to pull what we need from the air is astronomical.

[ Parent | on HN ]
Re:100% renewables doesn’t equal zero-carbon energy, and the... by pfdietz on Tuesday June 04, 2019 @08:28AM (#20094297)
Nothing "pulled from air" in ammonia production is expensive. The energy intensive part is making hydrogen, and then pressurizing the nitrogen and hydrogen.

Currently, hydrogen is produced from natural gas, but renewable hydrogen from electrolysis would be fine. And at the rate the cost of solar is declining renewable hydrogen is going to be competitive soon (nuclear hydrogen, not so much.) And if renewables are over-installed to deal with intermittency there will be a lot of excess power intermittently available. The key technology here would be mediocre efficiency, but low capital cost, membraneless electrolyzers.

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