transpired that the couple were in no debt to Scottish Power. In 2020, The Observer gave Scottish Power an award for the year's "worst customer service" for "its singular pursuit of revenue", including sending bills, debt collectors' letters and the threat of bailiffs to people who did not use its services, then refusing to register their complaints. In January 2021, the Consumers' Association Which? magazine ranked Scottish Power the worst-performing supplier for customer service and the second worst supplier overall in their annual review of energy suppliers. Operations Energy Retail The Energy Retail division contains ScottishPower Energy Retail Ltd which holds the gas and electricity supply licences. At the end of September 2020, this division held an 8.9% share of the domestic electricity supply market and 7.6% share of the domestic gas supply market. This represents a slight decline from the previous year and also the lowest market share held by the company since 2004. Also included in this division is SP Dataserve Ltd which provides a range of metering services including data collection, analysis and revenue protection. Energy Networks The Energy Networks business contains three asset owning companies SP Transmission Ltd – holds the transmission licence for central and southern Scotland and owns the part of the Moyle Interconnector with Northern Ireland Electricity, SP Distribution Ltd – holds the distribution licence for central and southern Scotland and SP Manweb Plc – holds the distribution licence for North Wales, Merseyside, and Cheshire. A fourth asset management business SP Power Systems Ltd maintains and repairs the distribution networks on behalf of the owners and acts as the distribution network operator. The operation of the transmission grid is carried out by National Grid plc. Energy Wholesale Energy Wholesale contained two companies ScottishPower Generation Ltd which formerly generated 6,200MW of electricity power in the United Kingdom using coal-fired thermal power stations, combined cycle power stations, hydro-electric schemes, pumped storage generation and were acquired by Drax in 2018. In 2006, ScottishPower Renewables (SPR) was granted permission to build Europe's largest on-shore windfarm. The 322 MW / 140 turbine site cost an estimated £300m and covers approximately of moorland south of Glasgow. By 2014, SPR had a portfolio of over 1,250 MW of operating windfarms, including the recently expanded Whitelee with a total generation capacity of 539 MW, making it Europe's largest windfarm. Also within this division is ScottishPower Energy Management Ltd which is responsible