While Poland's ruling Law and Justice party (PiS) has said it will reduce reliance on Russian oil and gas, coal imports from Russia rose to 9.3 million tonnes from the start of the year until the end of September from 5.2 million over the same period a year ago, the data showed.

Coal imports from Russia in the first three quarters of the year are already higher than in 2017 and 2016 when Poland bought from Russia 8.7 million tonnes and 5.2 million tonnes respectively.

Poland's annual coal imports had already risen in 2017 to almost 13 million tonnes from 8.3 million in 2016 as domestic production fell because of limited investment in Polish state mines. Poland also turned to the United States for increased supplies.

In the first three quarters of this year, Poland's thermal coal imports from the US increased to 771,253 tonnes from 151,083 tonnes a year earlier.

Poland, which is hosting UN climate talks over the next two weeks, generates most of its electricity from coal.

The PiS, which won the 2015 election partly on promises to maintain coal, plans to reduce the use of the polluting fuel, but gradually. A draft version of Poland's long-term energy strategy lays out plans to reduce the share of coal in power production to around 60 percent by 2030 from around 80 percent now.

Before the global climate talks started on Sunday, the energy ministry announced it planned to build a new coal mine, partly in response to the rising coal imports and dwindling Polish output. Poland's hard coal production fell to 66 million tonnes last year from 71 million in 2016.