What is a transmission network?

The transmission network is the highest voltage electricity network in the UK – the ‘motorway network’ of the energy world. It transmits large quantities of electricity over long distances via wires, subsea cables and underground cables, carried on a system of mainly metal towers and large substations. It is the network that transports the electricity generated from generation assets such as wind farms and power plants to the distribution network where it is then distributed to homes and businesses.

Transmission voltages in Scotland are 132kV*, 275kV and 400kV. Larger generation schemes usually connect to the Transmission system.

The lower voltage parts of the system are called distribution networks. In Scotland, these local networks operate below 132kV whereas in England the distribution network includes 132kV.

The reason the voltage has to be so high when being transported on a transmission network is to reduce the energy loss due to resistance that occurs over long distances. As the electricity is transported from the generation asset, along the transmission network, and then to the distribution network, the voltage is gradually decreased until the distribution network then converts it to a safe voltage for homes and businesses to use via transformers.

SSE's transmission portfolio

renewable energy connected to the network
increase in network size by 2030
homes and businesses powered by 2030

SSE's operating expertise

Scotland’s transmission network has a strategic role to play in supporting delivery of the UK and Scotland’s Net Zero targets. We’re already a mass exporter of renewable energy, with around two-thirds of power generated in our network area exported to demand centres further south. By 2050, the north of Scotland is expected to need 40GW of low-carbon energy capacity to support net zero delivery. For context, SSEN Transmission currently has over 9GW of renewable generation connected in the north of Scotland.

SSEN Transmission actively seek to improve their understanding of the challenges facing the GB transmission network and find new ways to overcome these challenges. They are collaborating with our customers, stakeholders, industry innovators, and other transmission owners (TOs) to share ideas, research new concepts for our network, and maximise the value and benefits of pioneering technologies.

More on transmission

Meeting Government and net zero targets by 2030

A network for net zero

Find out more
Connecting Shetland to the GB mainland for the first time

Shetland HVDC link

Find out more
Our transmission network business unit

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SSEN Transmission