Well, we’ve a single cable coming over from France that makes up about 3% (I think) of our total electricity supply. So “French Nuclear” should be a bigger entry in that table than coal, solar, hydro or bio. That’s not the only import, either, so it’s not completely impractical for the missing percentages to be imports.

https://en.wikipedia.org/wiki/HVDC_Cross-Channel

You can only store rational numbers as a ratio of two numbers, and there’s infinitely times more irrational numbers than rational ones - as soon as you took (almost any) root or did (most) trigonometry, then your accurate ratio would count for nothing. Hardcore maths libraries get around this by keeping the “value in progress” as an expression for as long as possible, but working with expressions is exceptionally slow by computer standards - takes quite a long time to keep them in their simplest form whenever you manipulate them.

Good news is that it’s such a bastard to program efficiently that most games don’t make full use of it and you can get away with a certain amount of approximation in its behaviour for speed. Nice work, Sony.

Compare that with z80 or 6502 based machines, where you need to be beyond cycle perfect in some cases. Need to simulate every rising and falling edge for the CPU and its coprocessors in a SNES if you want to avoid every edge case, for instance.