Energy firm ScottishPower has reported a 77% profit increase in its first half of the year, totaling GBP483 million for the six months ending September 30, 2006.

Behind the profit rise was the rise in wholesale prices, and strong performance at the utility’s coal-fired power plants. ScottishPower imposed gas and electricity increases upon consumers in June.

Although the surge in profits from the increase of wholesale prices makes for a positive outlook for the company, returns on its retail business remained poor.

As a result, we have deliberately constrained customer growth and our customer numbers have been held broadly stable during the period, ScottishPower said.

The company is reportedly under negotiations with the Spanish specialist wind power firm Iberdrola over a potential takeover deal. According to the BBC, the Spanish firm may place a bid of GBP12 billion, although ScottishPower’s results release has not prompted an immediate takeover bid as some had expected.