Our businesses

National Grid is an international electricity and gas network company.

  • Electricity

    Transmission

    Transmission systems generally include overhead lines, underground cables and substations. They connect large generation plant to the distribution systems, often over long distances.

    We own and operate the transmission network in England and Wales; we operate, but do not own, the Scottish networks.

    In the US, we both own and operate transmission facilities spanning upstate New York, Massachusetts, New Hampshire, Rhode Island and Vermont.

    System operator (UK only)

    As system operator (SO) for Great Britain, and also as SO for the offshore electricity transmission regime we coordinate and direct electricity flows onto and over the transmission system, balancing generation supply and user demand. Where necessary, we contract with sources of both supply and demand to increase or decrease their generation or usage.

    In the US, these services are provided by independent system operators.

    Distribution (US only)

    Distribution systems typically work at lower voltage s than transmission systems over networks of overhead lines, underground cables and substations. They take over the role of transporting the electricity from the transmission network, and delivering it to consumers at a voltage they can use. In the northeastern US, our distribution networks serve around 3.5m customers.

    We do not own or operate electricity distribution networks In the UK.

    Supply (US only)

    The supply of electricity requires our businesses to buy power and then sell it onto customers for the cost at which it was purchased. It also involves customer services, billing and the collection of customer accounts.

    The five states in which we operate in the US are deregulated and consumers choose their own energy supplier. Where customers choose National Grid, they pay us for distribution and electricity costs. Where they choose to buy electricity from another provider, they pay us for distribution only.

    Generation (US only)

    Generation is the production of electricity from thermal power stations, as well as renewable sources such as wind and solar.

    In the US, we open and operate 50 fossil fuel powered stations on Long Island, totalling 3.8GW, and 21 MW of solar generation in Massachusetts.

    Interconnectors

    Transmission grids are often interconnected so that energy can flow from one country to another. Great Britain is linked via interconnectors with France, Ireland, Northern Ireland and the Netherlands. National Grid owns part of the interconnectors with France and the Netherlands.

    We jointly own and operate a 224km interconnector between New England and Canada.

  • Gas

    Transmission

    We are the sole owner and operator of gas transmission infrastructure in Great Britain.

    In the US, we hold a minority interest in an interstate gas pipeline regulated by FERC.

    Transmission systems generally include terminals, pipes, pressure reduction stations and compressor stations. They may also include storage facilities, including liquefied natural gas (LNG) storage. They connect sources of gas, e.g. offshore gas fields, through terminals and pipelines to the distribution systems.

    Compressor stations located along the network play a vital role in keeping large quantities of gas flowing through the system, particularly at time of high demand. The gas transmission system has to be kept in balance, which is achieved by requiring gas suppliers to source more or less gas contracting with customers to reduce demand and/or using stored gas.

    Distribution

    In the UK, gas leaves the transmission system and enters the distribution networks at high pressure. It is then transported through a number of reducing pressure tiers until it is finally delivered to consumers. There are eight regional gas distribution networks, four of which are owned by National Grid delivering gas to around 10.9 million customers on behalf of 37 shippers.

    In the US, gas is delivered by the interstate pipeline companies to local distribution networks. Each local distribution company has a geographically defined service territory and is the only local distribution company within that territory. These companies are regulated by the relevant local state’s utility commission. We have gas distribution networks in Upstate and Downstate New York, Massachusetts and Rhode Island, serving around 3.6 million customers.

    Importation

    In the UK, we own and operate an LNG importation terminal and storage facilities at the Isle of Grain in Kent (Grain LNG). Grain LNG charges customers under long-term contracts for various services, including access to our importation terminal, storage facilities and capacity rights.

    In the US, we own and operate LNG storage and vaporisation facilities to support our gas distribution businesses as well as an LNG storage facility in Providence, Rhode Island, where we store gas for third parties for a fee. We also buy gas directly from producers and LNG importers for resale to our customers.

    Supply and metering

    We do not supply gas in the UK. However, we own National Grid Metering, which provides meters and metering services to supply companies, under contract. In the US, metering is part of our distribution businesses.

    In the UK, customers pay the supplier for the cost of gas and getting it to them. Suppliers pay shippers and we transport the gas through our network on behalf of shippers. It is these shippers who pay us transportation charges.

    In the US, gas distribution companies, including National Grid, sell gas to consumers connected to their distribution systems.

    In most cases in the US, where customers choose National Grid, they pay us for distribution and gas costs. Where they choose to buy gas from third parties, they typically pay us for distribution only and pay the third party supplier for the gas and upstream transmission cost.