alt Hacker NewsA huge share of the gypsum used in drywall is *synthetic gypsum* — a byproduct of flue-gas desulfurization (FGD) at coal-fired power plants. When SO₂ is scrubbed from exhaust using limestone, the reaction produces calcium sulfate dihydrate, chemically identical to mined gypsum. In the US, FGD gypsum has accounted for roughly half of all gypsum consumed by the wallboard industry at its peak.
The "cheap, uniform, and free of defects" story is partly a story about coal. The drywall industry scaled on the back of an abundant, nearly free waste stream from the energy sector. It's a classic example of industrial symbiosis — one industry's pollution abatement becomes another's feedstock.
And it cuts the other way now: as coal plants shut down across Europe and North America, synthetic gypsum supply is shrinking. The drywall industry is facing a real raw material squeeze, with manufacturers having to shift back toward mined gypsum or find alternative sources. There's ongoing work on using phosphogypsum (from fertilizer production) but that comes with its own radioactivity concerns.
For someone in your position this is particularly relevant — the "wonder" of drywall is entangled with the fossil fuel economy in a way that makes earth-based construction methods look increasingly attractive as that supply chain unwinds.
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I used to work for a drywall manufacturer who still owned their own mines despite efforts to divest from them by some. They always viewed it as a structural advantage to still own them and not be wholly dependent on the coal plants (which effectively have conveyor belts going from the coal plants to the wallboard plants). I imagine as time goes on it'll become even more of an advantage for them to still own those mines as their competitors are forced to buy at highly inflated prices (or even from them) as coal shuts down.
> the "wonder" of drywall is entangled with the fossil fuel economy in a way that makes earth-based construction methods look increasingly attractive as that supply chain unwinds.
I keep thinking of that scene in Brazil where the hero, Harry Tuttle, opens a modular wall panel in Sam's apartment.
We standardized on 16 inch stud spacing here in the US a long time ago when we likely still used cement with a plaster skim coat on wood lath. Cutting up a board of nearly the same stuff feels primitive. You have to break open the wall to fix things.
To me the next logical step is a standard for modular walls that are laid out on a grid structure. I get that no one wants exposed screw holes but I can think of ways to hide them or make them part of a decorative pattern to blend them in. The coverings would be made to be cut to size as well. Wall panels would have to be environmentally friendly so wood is a first choice in natural and/or composite forms.
If you think this will look boxy then look up the passive house and notes on home building. Homes with a winding structure are difficult to seal reliably and roof so a boxy home is actually more economically friendly in terms of insulation to reduce HVAC energy consumption.
Fascinating. I wonder if supply constraints will make drywall recycling profitable.
Question: Would this process of creating synthethic gypsum leave any toxic chemicals from the scrubbing process at the coal power plant exhaust?
This reminds me a bit of Hank Green's recent video on why we don't recycle plastic. The answer is we frack a lot of methane for electricity and ethane is a byporoduct of that. You can flare it off or use it as a negative cost ingredient for polyethane / many other plastics. As long as we're using lots of fossil fuels the byproducts will be cheap. Anyone who has played gregtech or factorio or similar already has an intuition for this. The answer then becomes simple: if you want less plastic you must use less fossil fuel. They are one and the same.
https://youtu.be/325HdQe4WM4