RWE commissioned what it said was the world's most advanced lignite-fired power station near Cologne. The company said the twin-unit plant has a 43 percent efficiency rating and has a combined capacity of 2,200 megawatts.
RWE Chief Executive Officer Peter Terium said modernizing the company's conventional power plant portfolio was what's needed to improve the German energy mix.
"RWE is doing exactly what the transformation of the German energy industry is all about," he said in a statement.
Nuclear power dropped from 22.4 percent of the German energy mix in 2010 to 17.7 percent in 2011. German Chancellor Angela Merkel last year ordered the country's nuclear power plants closed in response to the meltdown of Japan's Fukushima Daiichi nuclear power plant in March 2011.
Germany gets more than 20 percent of its electricity from lignite power plants. RWE said its twin-unit lignite plant was developed with a total investment of $3.2 billion, one of its largest investments in its history.