BERLIN (AP) — German news magazine Der Spiegel reports that Chancellor Angela Merkel plans to discuss efforts to wean the country off coal with senior officials this month.

Spiegel reported Saturday that Merkel has invited governors from four coal-producing German states to the chancellery for a meeting on Jan. 15.

The date is about two weeks before an expert committee is expected to deliver a report on when and how Germany should stop burning coal to generate electricity.

Germany recently closed its last black coal mines , but continues to extract and burn lignite , a dirtier and cheaper form of coal.

Recent figures show Germany produced more electricity from renewable sources than from coal for the first time last year.

Scientists say coal use has to end by 2050 to curb global warming .