It's not that stupid (and the EU even did the same thing first ... it's just that most of the British media reporting on how much more effective their windfall

It's not that stupid (and the EU even did the same thing first ... it's just that most of the British media reporting on how much more effective their windfall taxes were downplayed or omitted the fat that most of the money was coming from renewable generation). If the UK ever builds the kind of renewable capacity needed for our climate goals those windfall profits will go pop because they only exist due to electricity prices being based on the most expensive generation needed to meet demand, which is currently natural gas. Once renewables are pushing gas out of the generation mix most of the time that price drops to nearly zero except when the renewables aren't performing well. Basically, the only way for these profits to encourage investment is if renewable companies think they can sandbag the energy transition. (The renewable generation that the Conservative government is pushing for isn't really affected by this because some time ago, they changed how the subsidies were structured into contracts for difference where the companies get a fixed price with the government paying back or receiving the difference from the market price. Profits from generation covered by those CfDs are not subject to any windfall tax.)