- German Economy Minister Sigmar Gabriel has sought to reassure energy companies the government has no plans to shut down lignite mines, according to a copy of a letter addressed to works councils and seen by Reuters.
"Both power from black coal as well as brown coal will definitely have a significance in the long term for a secure and affordable electricity supply in Germany. And with it lignite mines too," Gabriel wrote in the letter dated March 31.
Lignite, often referred to as brown coal and the dirtiest of all energy sources, accounted for 25.6 percent of Germany's power output last year, according to industry association BDEW, second only to renewables, which took a 25.8 percent share.
Environmental groups have criticised Germany's growing reliance on brown coal and warn it may miss its targets to cut greenhouse gas emissions by 40 percent by 2020 from 1990 levels.
As part of a climate package approved by the government last year, coal operators are being forced to slash their emissions by at least 22 million tonnes by 2020, equivalent to shutting about eight coal plants.
The government also plans to force operators of coal plants to curb production at their oldest and most polluting power stations. But the move has sparked a backlash from energy groups as well as German states who are worried about a loss of jobs.
Gabriel said Germany could not exit coal at the same time as it is withdrawing from nuclear power and would need brown coal to guarantee a secure and affordable power supply.
RWE, Germany's largest power producer, heavily relies on lignite, its biggest power source, which accounted for 37 percent of the company's power production in 2014. Renewables were its smallest contributor at just 5 percent.
Longer life-spans for lignite plants would also be a boon for Swedish utility Vattenfall, which is seeking a buyer for its German brown coal activities, a plan that largely depends on regulation and political assurances.
However, the Vattenfall works council -- a group of employees within the company who represent the staff -- said they were not reassured by Gabriel's letter.
"We are very worried about jobs. The governments plans can't be implemented in this form. Thousands of jobs are on the line," Rainer Kruppa, head of Vattenfall's works council, told Reuters.