ScottishPower, a subsidiary of Basque giant Iberdrola, said on Wednesday earnings (EBITDA) from its generation and supply business soared 306% to £165.8 million in the first half of 2018 despite customer numbers falling to 4.9 million compared to 5 million at the end of the first quarter.

Earnings from ScottishPower’s SP Energy Networks division rose 3% to £399.9 million, and earnings from the ScottishPower Renewables business soared 27% to £205.1 million.

Parent firm Iberdrola said it made “ordinary net profit” of €1.368 billion in the first half of 2018, 27% more than in the same period last year.

Iberdrola’s revenues rose 17.5% to €17.586 billion in the first half.

ScottishPower CEO Keith Anderson said: “All of our business areas are performing in line with expectations.

“Our investment in onshore wind last year has seen an increase in electricity generated, and excellent progress has been made on delivering the £2.5 billion East Anglia ONE project.

“We expect first generation of electricity next year.

“Networks also continues to see major investment.

“We are delivering a smarter and more robust grid system to support renewable energy connections, as well as planning for the anticipated increased uptake of electric vehicles in the years ahead.

“Generation and Supply has improved on the poor results in 2017, moving towards a more typical year.

“We expect further details on the proposed Price Cap in the second half of the year, and expect the market to remain challenging.”