ScottishPower upbeat after figures reveal no change in customer numbers

The utility, which is owned by Spain’s Iberdrola, added that half-year earnings were higher despite a sharp drop in demand due to warmer weather. ScottishPower had 2.2 million customers in gas and 3.4 million for electricity, with the overall figure of 5.6 million the same as December and June last year.

Last week rival SSE said it lost 110,000 customers over the last three months, taking its base down to nine million, despite freezing prices.

Iberdrola said UK earnings rose 8.5 per cent to 244 million euros (£192m), even though margins in its retail supply business were lower. The company raised gas tariffs by 8.5 per cent and electricity prices by 9 per cent in December, although some of this was later reduced due to a shake-up of green levies.

Scottish Power said it made up for the first half earnings deficit in retail supply through its generation business, which has benefited from an 11 per cent rise in output from renewable energy sources such as wind farms. The firm said the Carbon Floor tax, a levy on fossil fuels used to generate electricity introduced last April, cost it £31m during the period.

The warmer weather meant electricity demand fell 6.7 per cent compared to a year ago, while gas demand fell 15.9 per cent.

This took its overall share of the UK power market down to 6.1 per cent from 6.6 per cent over the last 12 months.

Scottish Power is part of the UK’s Big Six group of energy firms – npower, SSE, EDF, E.On and British Gas – who supply around 95 per cent of the country’s power.

They have come under fire for raising prices and now face a Competition and Markets Authority probe to see if there is enough competition in the UK energy market.