"The electricity bill for private customers will be 30 percent higher in 2020 than it is today," Vattenfall Europe chief Tuomo Hatakka told the Frankfurter Allgemeine Zeitung newspaper in an interview.
By contrast, the wholesale price of electricity "will not increase significantly," Hatakka said.
Private customers will have to foot the bill for the investments needed to switch to renewable sources of energy and the related network infrastructures, he argued.
Germany has decided to pull out of nuclear power, and brought the date forward to 2021 in the wake of the Fukushima disaster in Japan – while also reducing its dependence on fossil fuels.
The aim is to meet 35 percent of German energy demand with renewable sources such as solar and wind by 2020 (compared with 20 percent at present) and as much as 80 percent by 2050.
Like Germany's biggest power suppliers, E.ON and RWE, Vattenfall Europe is considering suing the German government for damages over the decision to abandon nuclear power, Hatakka said.
The country's biggest power utility E.ON alone wants at least €8.0 billion, after Berlin forced energy suppliers to shut down their profitable large-scale power plants and also levied a tax on the reactors' fuel for their remaining lifespan.
Both E.ON and its next biggest rival RWE have already filed complaints with the constitutional court, arguing that the nuclear exit decision has harmed their proprietary rights as they had to shut down reactors early.
"If appropriate compensation is necessary, then we will file a suit too," the Vattenfall Europe chief said.
"We respect Germany's decision to pull out of nuclear energy. But we expect fair compensation for the damages we've suffered from the decision," he said.