The network map

Your distribution network decides which plans you can buy and what they cost, and most people have never heard of theirs. Find your postcode here to see it, and what the cheapest plans on it charge. Every postcode on the same network is the same colour, because a plan's only geography is its network. Fourteen electricity zones and about two dozen gas ones cover the whole country, and prices do not vary inside one.

That is also why this map is for orientation rather than comparison: to see what each retailer charges in your network, and how differently the same retailer is priced in the next one, use the rate grid.