After a mid-August decision to change how it works at home, German energy company RWE said it was shaking up its British team after disappointing results.

The Germany company said net operating results from its British subsidiary, RWE npower, dropped 60 percent from the first six months of 2014. In response, the company said it was promoting Chief Operating Officer Paul Coffey to the post of chief executive officer. Current CEO Paul Massara is leaving the company along with Chief Financial Officer Jens Madrian.

"It is clear that RWE npower's domestic business is not performing in the way that our customers, shareholders, or our employees demand," Coffey said in a statement.

The parent company, the largest utility in Germany, said in a mid-August statement it was restricting management along conventional, retail, grid and renewable operations while at the same time eliminating redundancies on board committees and reigning in its subsidiaries.

In its statement on the board reshuffling, the company said it was working diligently to overcome problems particular to the British subsidiary by the end of next year.

"I am looking forward to working with my management team, those already in npower and those joining, as we build on the foundations already laid to refocus our efforts to improve our performance," Coffey said.