Energy company E.ON AG says its first-half earnings leapt following an agreement on long-term gas supply contracts with Russian gas producer Gazprom OAO.

E.ON said Tuesday that it expects underlying net earnings of about €3.3 billion ($4.1 billion) for the January-June period — compared with some €900 million a year earlier.

It said that, in addition to the settlement with Gazprom which it announced last month, the year-on-year comparison was flattered by one-time costs the company faced in 2011 from Germany’s decision to accelerate its phase-out of nuclear power.

Two of E.ON’s nuclear reactors were among eight older ones in Germany that were switched off after Japan’s Fukushima disaster.

E.ON says it’s upholding an increased full-year forecast issued last month. Its full earnings report is due next Monday.