Sales of all domestically mined coal totalled around four million tonnes in 2018, compared with 4.5 million tonnes last year, it said.

This is in line with a national schedule to stop domestic mining completely by Dec. 31, 2018, in favour of cheaper imports.

By setting the 2018 deadline, marking the end of 200 years of coal mining in the Ruhr valley, Germany won a battle with the European Commission over subsidies after the Commission had demanded a complete withdrawal by 2014.

GVSt's 2017 numbers were published in its annual report, while the 2018 estimate was made separately in reply to an enquiry.

Germany also mines brown coal, or lignite, which is cheaper but highly polluting.

Despite the shift towards renewable energy, both types of coal taken together still account for 36 percent of power consumption.

Hard coal plants are fuelled with imported coal. Hard coal importers group VDKI said in the summer that imports this year could fall to 45 million tonnes, down 12 percent from 2017, amid growing competition from renewable energy.