Frequently asked questions

A distribution network operator (DNO) holds the distribution licence for one of the 14 licence areas in Great Britain and owns and runs the network there, from the grid supply points down to homes and businesses. The 14 areas are held by six groups: UK Power Networks, National Grid Electricity Distribution, Northern Powergrid, Electricity North West, SP Energy Networks and SSEN Distribution. An independent distribution network operator (IDNO) also holds a distribution licence but has no fixed area: it builds or adopts networks, usually for new housing, commercial or energy developments, that connect to a DNO's network. See our organisations pages.

An independent connection provider (ICP) is a contractor that builds the contestable parts of a new connection, such as the cables and substation on a development site, as an alternative to the DNO doing all the work. ICPs need accreditation under the National Electricity Registration Scheme (NERS), run by Lloyd's Register, and the finished assets are adopted by the DNO or an IDNO.

The transmission owners build, own and maintain the high-voltage network: National Grid Electricity Transmission in England and Wales, SP Transmission in central and southern Scotland and SSEN Transmission in the north of Scotland. Offshore transmission assets are owned by offshore transmission owners (OFTOs). The National Energy System Operator (NESO), publicly owned since October 2024, operates the system in real time, runs the transmission connections process and leads long-term network planning. In Northern Ireland, NIE Networks owns the network and SONI operates the transmission system.

Ofgem regulates the GB network companies through their licences and price controls, and decides on changes to the industry codes. The Department for Energy Security and Net Zero (DESNZ) sets government policy. In Northern Ireland the regulator is the Utility Regulator.

The connections queue grew far beyond what the system needs, with many projects that were unlikely to be built holding early dates. Reform replaced first come, first served with a gated process run by NESO: projects that meet readiness criteria and fit the government's Clean Power 2030 plans can be given firm dates at Gate 2, and the existing queue is re-ordered on the same basis. Ofgem approved the main code changes in 2025. Follow the connections reform topic for the latest steps.

Contestable works are parts of a connection that a customer can choose to have built by an accredited ICP rather than the network company, such as the new network on a site. Non-contestable works must be done by the network company, typically the point of connection to its existing network and any reinforcement of it.

A connection where the customer agrees that their import or export can be reduced at times when the network is constrained. In return they can usually connect sooner or for less than waiting for reinforcement. Terms vary between network companies.

It depends on size and location. Large projects, and those in areas where the distribution network can't take them, connect directly to the transmission network. Smaller projects connect to the distribution network but can still need transmission works or an assessment of their impact on it. The size thresholds are lower in Scotland than in England and Wales.

They are the charges that recover the cost of running the networks. Distribution use of system (DUoS) charges pay for the distribution networks and are set by each DNO using common methodologies. Transmission network use of system (TNUoS) charges pay for the transmission network, are set by NESO, and vary by location, so generators far from demand, such as in the north of Scotland, generally pay more.

RIIO (Revenue = Incentives + Innovation + Outputs) is Ofgem's framework for setting how much the network companies can earn and what they must deliver. RIIO-ED2 covers the distribution networks from April 2023 to March 2028. RIIO-T3 covers the transmission networks from April 2026 to March 2031. Ofgem is developing the next distribution price control, RIIO-ED3. Follow the price controls topic.

Since April 2023, demand customers connecting to the distribution network no longer pay for reinforcement at the voltage level above their connection, and generators pay less of it than before. The rest is recovered through DUoS charges across all users. The change came from Ofgem's Access and Forward-looking Charges review.

A scheme run by Ofgem to support large long-duration electricity storage projects, such as pumped hydro. It sets a floor on a project's revenue, so investors are protected if markets underpay, and a cap above which revenue is returned to consumers. Projects apply in windows and are assessed by Ofgem. See long-duration storage.

As well as building and maintaining networks, distribution companies are expected to act as distribution system operators (DSOs): forecasting and managing power flows, buying flexibility from customers to avoid or defer reinforcement, and sharing network data. Under RIIO-ED2 each DNO has separated its DSO function and is measured on it. See DSO and flexibility.

The site searches Google News and a few RSS feeds three times a day. Each new headline is checked once by an AI classifier, which keeps stories about the electricity networks and how projects connect to them, and drops consumer offers, share-price stories and projects with no grid angle. It also assigns a category, topics, an organisation and a region. Every headline links to the original publisher. See about the site.

A named transmission line, cable, HVDC link, interconnector or major substation, an offshore wind farm's grid connection, or a generation or storage project of 100MW or more. The big projects tracker lists each reported milestone, from proposal and consent to construction and energisation.

The policy timeline lists the main price control and reform milestones, and the glossary explains the terms used in the news. The weekly and monthly round-ups summarise the news.