ScottishPower's £1.5bn Whitelee Repower Signals Britain's Ageing Wind Fleet Needs Rebuilding
Plans to double the UK's largest onshore wind farm from 539 MW to 1 GW by 2035 put the cost of Britain's wind fleet rebuild into focus.
ScottishPower announced on Wednesday (2026-07-22) a £1.5 billion plan to repower Whitelee, the UK's largest onshore wind farm, lifting capacity from 539 MW to 1 GW by 2035, according to Energy Voice and Montel.4,3
The project would replace 215 existing turbines on Eaglesham Moor, south of Glasgow, with 124 machines standing around 250 metres tall. The drop from 215 to 124 units reflects the pace of turbine development: modern machines generate substantially more output per unit than first-generation equipment, and Energy Voice framed the announcement explicitly as the opening move in a broader rebuild of Britain's first-generation onshore fleet.4
Britain still needs to roughly quadruple current offshore wind capacity to reach its 50 GW target by 2030, according to The Economist. With new onshore sites politically difficult in many parts of the country, repowering ageing facilities like Whitelee offers a faster route to incremental capacity than starting greenfield, which is part of what makes the Whitelee announcement a project to track rather than simply a single utility's capital plan.1,4
Scotland's wind resource is large by European standards. The country has 4.3 GW of installed offshore wind capacity, placing it fourth in Europe, backed by a development pipeline exceeding 40 GW, more than half of it floating, according to Stephen Gethins, Scotland's minister for energy, external affairs and Europe, speaking at a Manchester conference in June 2026 (2026-06-17). He put the global capital expenditure value of that pipeline at around £100 billion.2
Converting pipeline into operational capacity keeps running into grid connection economics. NESO data cited by Gethins showed the current connection cost regime could cost Scottish clean energy projects up to £1 billion by 2030-31, while comparable projects in England and Wales would receive payments to connect, a disparity he described as punitive and unfair. The distortion falls on onshore and offshore projects alike.2
Wales faces a version of the same constraint. Three operational offshore wind farms generate 726 MW, with floating wind potential identified in the Celtic Sea. Scotland and Wales pressed Westminster jointly at the June 2026 (2026-06-17) conference for an overhaul of the offshore wind support framework. Whether Westminster moves on connection costs before Whitelee needs its grid connection agreement will feed directly into ScottishPower's investment arithmetic on the project.2
The turbine supply picture adds a separate cost variable. Chinese manufacturers accounted for more than 70% of new global wind installations in 2024, according to Bruegel, the Brussels think-tank. Domestic overcapacity compressed margins: China had the capacity to produce 99 GW-worth of turbines in 2024 but installed only 87 GW, and Chinese turbine-makers' operating margins before depreciation and amortisation fell from an average of 18% in 2021 to 10% in 2024, dropping below European counterparts for the first time in years. Wood Mackenzie data show Chinese manufacturers added 9 GW of overseas installations in 2025, up from 2 GW in 2024 and 1 GW in 2023.1
ScottishPower has not disclosed a turbine supplier for Whitelee. Security and trade-policy concerns have followed Chinese manufacturers into European markets, and The Economist reported in May 2026 (2026-05-17) that protectionism may yet halt their European advance. How the UK government positions itself on Chinese turbine supply, weighing procurement costs against security, will shape Whitelee's economics and the broader cost envelope for Britain's onshore fleet rebuild.1,4