A dozen Chinese shipping vessels have transited the waters of the Northern Sea Route (NSR) in 2017, more than double the total of five in 2016.

That’s largest number of non-Russian vessels ever to operate in the Arctic. China also deployed the icebreaker Xue Long for three months in the Arctic Ocean.

Five of the voyages included three westbound from Asia to Europe and two eastbound from Europe to Asia. Three of the transits involved delivering modules for Yamal LNG. Guangzhou Salvage also delivered modules for Yamal LNG. China’s National Offshore Oil Corporation  and China’s Oilfield Services Limited conducted seismic and drilling activities in the Kara Sea.

China has made no secret of its interest in exploiting the Arctic for its potential shipping routes, although China is not itself an Arctic nation, and has added the Northern Sea Route to its Belt and Road initiative. The retreat of Arctic Ocean ice, thanks to the warming of the seas, has opened the potential for increased shipping through the Arctic, which would reduce fuel consumption and costs for international freight transportation.

Three COSCO vessels carried windmill-related cargo to and from Denmark, each spending nine days sailing the NSR. Another vessel, the Da An departed from Tian Jin, China with unknown cargo, transiting the NSR for eight days before arriving in Cuxhaven, Germany. The Tian Le sailed from Cuxhaven to Tomakomai, Japan, with unknown cargo, spending seven days on the NSR and arriving in Japan after three weeks. All five vessels shortened their voyages by about 10 days by sailing via the Northern Sea Rout, rather than the Suez Canal.

China’s shipping activity in the north highlights the busiest Arctic shipping season on record. A total of 10.2 million tons are expected on the NSR by the end of the year, an increase of 36 percent over 2016.

Officials expect maritime traffic on the northern route to double in the next year.