While not familar with how things are in the UK, I understand DNO, which is the layer of the distribution network. Which means the part from power-plant->substa

While not familar with how things are in the UK, I understand DNO, which is the layer of the distribution network. Which means the part from power-plant->substation->high voltage line to at least one other substation near a city, or so. That does not include middle voltage into the city, or further downstepping until it is fit for your wall socket or similar. If it claims to, it is a political fiction like so many other. In reality transmission losses from the one virtual plant powering the grid to your wall socket range from about 50% to 60% depending on the grid and many other factors. Anything else is wishful thinking.