The company's Chief Financial Officer Marcus Schenck also said during a conference call that the company's profits would not recover in the near term.
"Based on our current financial planning, we expect results in 2012-2014 to be on a much lower level than 2010," he said.
At 5:48 a.m. EDT, shares in E.ON -- which have lost about a third of their value since the beginning of the year -- were down 0.5 percent as one of only four decliners in Germany's DAX index, hitting their lowest level since late 2003.
E.ON said on Wednesday it now expected 2011 adjusted earnings before interest, depreciation and amortization (EBIDTA) of 9.1-9.8 billion euros, down from a previous outlook range of 10.7-11.4 billion.
It also lowered its outlook for full-year adjusted net profit to 2.1-2.6 billion euros, from 3.0-3.7 billion.
"Although the share price has reflected an anticipated adjustment of E.ON's financial guidance over the past few weeks already, we believe that the actual outcome of the guidance adjustments will come as a little shock to the market," said Sebastian Zank, analyst at Silvia Quandt.
E.ON said it was to overhaul its business, including up to 11,000 job cuts in the medium term -- 14 percent of its total workforce -- as it became the latest casualty of Germany's decision shut down all nuclear plants by 2022.
"We are not immune to negative changes in our Markets," E.ON Chief Executive Johannes Teyssen said.
E.ON -- which also cut its dividend to 1.00 euro for 2011, down from 1.30 euros -- added the job cuts would primarily affect administrative functions.
On Tuesday, peer RWE reported a 40 percent drop in first-half core profit, which it also blamed on the nuclear phase-out that had previously hit smaller peers EnBW and Vattenfall VATN.UL.
Analysts are also concerned about E.ON's heavy net debt -- currently at 33.6 billion euros -- which it piled up as a result of major acquisitions in recent years, while rating agency S&P has put the company's credit outlook on negative following the German government's nuclear exit.
First-half adjusted EBITDA reached 4.3 billion euros, while adjusted net income came in at 900 million. Analysts had expected adjusted EBITDA of 4.69 billion euros and adjusted net profit of 1.16 billion.
EurActiv with Reuters