We own and operate the electricity transmission network in England and Wales, with day-to-day responsibility for balancing supply and demand. We operate but do not own the Scottish networks. Our networks comprise approximately* 7,200 kilometres (4,474 miles) of overhead line, 1,500 kilometres (932 miles) of underground cable and 342 substations.
* AR 2016/17 figures
We are moving away from a historical reliance on large thermal power generation and there is now a greater diversity of supply and flexible demand than ever before. Therefore, the electricity transmission network has a central role to play in the future energy mix, with evolving roles enabling a range of possible energy futures for the long-term benefit of consumers.
Transmission systems generally include overhead lines, underground cables and substations. They connect generation and interconnectors to the distribution system.
We own and operate the transmission network in England and Wales. We operate but do not own the Scottish networks. We are also working in a joint venture with Scottish Power Transmission to construct an interconnector to reinforce the GB transmission system between Scotland and England and Wales.
Generation is the production of electricity from fossil fuel and nuclear power stations, as well as renewable sources such as wind and solar. We do not own or operate any electricity generation in the UK.
Transmission grids are often interconnected so that energy can flow from one country or region to another. This helps provide a safe, secure, reliable and affordable energy supply for citizens and society across the region. Interconnectors also allow power suppliers to sell their energy to customers in other countries.
Great Britain is linked via interconnectors with France, Ireland, Northern Ireland and the Netherlands. We own part of the interconnectors with France and the Netherlands. We are also now entering the construction phase for two new interconnectors, between the UK and Belgium and the UK and Norway. We are continuing to work on developing additional interconnector projects, which we believe will deliver significant benefits to consumers. These include opportunities for interconnection with Iceland, Denmark and a further link with France.
We sell capacity on our UK interconnectors through auctions.
Distribution systems carry lower voltages than transmission systems over networks of overhead lines, underground cables and substations. They take over the role of transporting electricity from the transmission network, and deliver it to consumers at a voltage they can use. We do not own or operate electricity distribution networks in the UK.
The supply of electricity involves buying electricity and selling it on to customers. It also involves customer services, billing and the collection of customer accounts. We do not sell electricity to consumers in the UK.