This map traces every cost that ends up on a GB gas bill, following the physical journey of gas from where it enters the country to where it is burned.
1. Extraction and import
GB gas comes from the UK Continental Shelf — now in long decline — and increasingly from imports. Suppliers buy this gas in the wholesale market, the single largest cost on most bills.
2. The National Transmission System
Gas then moves at high pressure across the National Transmission System (NTS) — the country-wide network of pipelines that carries gas from the import and extraction points to the regional offtakes. Using the NTS adds network and system charges — NTS Capacity and NTS Commodity — which suppliers pay through their Gas Distribution Network.
2b. National Gas Transmission
The NTS itself is owned and operated by National Gas Transmission (NGT), regulated by Ofgem under the RIIO-GT3 price control. NGT is the gas system operator: it monitors the volume of gas physically inside the NTS pipes, allocates capacity to shippers, publishes demand forecasts, and acts as the residual balancer when supply and demand on the network do not match.
3. Distribution
At pressure reduction stations gas steps down off the NTS into the Local Distribution Zones (LDZs), the regional networks that carry it the last miles to homes and businesses. This adds the LDZ tariff suite — System Capacity, System Commodity, Customer Capacity and Customer Fixed charges — plus the cost of gas physically lost on the networks.
4. The supplier
Almost every cost above is collected by the retail supplier and passed through to the customer. The supplier also carries its own costs: buying gas ahead of time (hedging), settling imbalances, running the business, funding bad debt, and earning a modest margin.
5. Consumption
Finally the bill lands with the customer — a home, an SME, an industrial site, or a gas-fired power station. Every bubble on this map is one component of what they pay.
Sitting above all of this is the regulatory and policy framework: the Department for Energy Security and Net Zero sets policy and law, and Ofgem regulates the market within it. They do not appear as a line on the bill, but they design and govern almost every cost shown here.