Scottish Power Transmission (SPT)

Scottish Power Transmission (SPT), legally SP Transmission plc, is the licensed electricity transmission owner for central and southern Scotland within the SP Energy Networks business of ScottishPower, itself part of the Iberdrola Group. SPT is responsible for transporting electricity from power stations, wind farms and other generation sources through a high‑voltage network that underpins supply to homes and businesses across its area and enables bulk transfers of power from Scotland into England and Wales. SPT’s network comprises over 4,500km of overhead lines, more than 600km of underground cables, over 150 substations and in excess of 100 grid supply points, where electricity is transformed from transmission to distribution voltages. Its system plays a crucial role in delivering the UK and Scottish Governments’ renewable energy objectives because it sits in an area of substantial renewable resource and provides the backbone for connecting and exporting that generation. The company develops RIIO‑T2 (2021–2026) and RIIO‑T3 (2026–2031) business plans with Ofgem, covering load‑related and non‑load‑related capital expenditure, network operating costs, cyber security, and data and digitalisation, and is subject to Ofgem’s Business Plan Incentive assessments and associated rewards or penalties. Recent determinations have also allowed funding for projects such as a new customer relationship management system. Operationally, SPT undertakes major reinforcement and connection projects to increase capacity for contracted renewable generation. Examples include reinforcement of the 400kV and 275kV substations at Kilmarnock South using a new 400kV gas‑insulated substation, which offers reduced footprint, high reliability and lower maintenance than air‑insulated alternatives. Through SP Energy Networks, SPT is also involved in multi‑billion‑pound transmission investment programmes and subsea links such as Eastern Green Link interconnectors, alongside ongoing innovation activities funded under Ofgem’s Network Innovation Allowance to improve asset performance and support the transition to a net zero electricity system.