For electric and gas that works as it's all just accounting. Energy company A buys futures for has and electricity and it all gets provided via the grid.
For trains it's much harder - yes, there are two providers on the WCML, but they're not equal (one runs faster trains) and as such there's zero real competition.
For trains it's much harder - yes, there are two providers on the WCML, but they're not equal (one runs faster trains) and as such there's zero real competition.