Your numbers are still crazy and wholly disconnected from reality. Panels do not, in fact require "decommissioning". They last much longer than 10 years: warra

Your numbers are still crazy and wholly disconnected from reality. Panels do not, in fact require "decommissioning". They last much longer than 10 years: warranties are 20 years, often more. Output may be degraded by up to 20% after that, but they continue producing. If cooled, they last longer. You can buy an electrolyser off the shelf today and plug it into any outlet. Efficiency is at least 60%, and rising; recent advances, which will hit market soon, have pushed it over 95%. A hydrogen car is much, much lighter than a battery electric car, so requires less energy to operate, but typical conversion losses today are larger than the difference. Nobody needs a hectare of panels for personal transportation use, whether for charging a battery electric car or synthesizing hydrogen for a hydrogen-electric car. A typical rooftop is plenty, at least in summer, depending on latitude. A private system sufficient to produce hydrogen for a car is in low tens of $thousands, not $millions. None of the above has anything to do with "scalability", which is a utility concern. Utilities can make hydrogen at whatever rate they have bought electrolysers for. The only thing stopping utilities is that if they had money for electrolysers, it would be far better used to buy more panels. Making shit up gives you bad numbers and false conclusions.