“Spanish consultancy AleaSoft Energy Forecasting recorded negative hourly electricity prices for all but one European energy market it analyzed during the first week of April, including in the Spanish and Portuguese markets for the first time. It also registered an all-time production record for photovoltaic energy in Portugal and the second highest value ever recorded in Italy”
That’s 17g or 17cc per cubic metre, not 17 litres!
In dry countries the relative humidity can be low - sub 40% is common. That said, the absolute water carrying capacity increases rapidly with temperature, so at 40C, the saturation mass is more like 50g/m3 and at 40%RH it still carries more water than 100%RH air at 20C.
You are correct, I got the wrong numbers. But with your numbers of course it makes even less sense.
You are right that you need to dehumidify a large volume of air (like, more than 150 cubic metres) to get enough water for a person, in a rationing scenario. That isn’t necessarily a huge problem; fans can move large volumes of air quite efficiently and dehumidifiers work more efficiently at higher temperatures, but your main point that it isn’t scalable on a population level is definitely true - it’s something you can do for off grid or survival situations, but not easily for domestic water supply.