RWE, Germany's second biggest-power supplier, said Tuesday earnings last year were hit by a one-billion-euro ($1.3-billion) charge related to the shutdown of some of its nuclear power plants.

RWE said in a statement its net profit fell by 33.9 percent to 2.479 billion euros last year and operating profit declined by 24.3 percent to 5.814 billion euros on a 3.1-percent drop in revenues to 51.686 billion euros.

"For us, fiscal 2011 was marked by difficult economic and political framework conditions," RWE said.

"The German government's nuclear energy decisions alone had a negative impact on the result of well over one billion euros."

In the wake of the nuclear disaster in Fukushima, Japan, last year, the German government decided to phase out nuclear power, forcing energy suppliers to shut down their profitable large-scale power plants and also levying a tax on the reactors' fuel for their remaining lifespan.

In addition, lower sales prices on the gas wholesale market and "persistently low margins in the electricity generating business all had an adverse effect on business performance," the group complained.

Nevertheless, chief executive Juergen Grossmann said RWE had undertaken measures "to get us through the trough quickly."

RWE was "therefore confident of maintaining the level of the previous year in 2012," he said, predicting that the trend would also continue into 2013 when "we still expect to be on a par with the result of 2011 this year, too."