Wulf Bernotat, the chief executive of Eon, surprised investors on Wednesday by announcing he would quit Germany’s biggest utility in 2010.

One of the country’s best known businessmen, Mr Bernotat, 61, told the company’s annual meeting in Essen that he would not seek the renewal of his contract next year. Without giving specific details, Mr Bernotat said he had developed concrete ideas for “new professional challenges” with an “international dimension”.