Qatari state-backed natural gas producer Qatargas says it has signed a long-term supply deal with a Japanese power company as the Asian nation increasingly relies on fossil fuels after a nuclear meltdown last year. Qatargas said Wednesday the deal with Kansai Electric Power Company covers shipments of half a million tons of liquefied natural gas annually for 15 years, beginning next year. Financial details were not disclosed. Qatar is the largest producer of LNG. KEPCO will get its gas from the Gulf nation's Qatargas 3 division, in which ConocoPhilips owns a 30 percent stake. Japan is the top importer of LNG. Demand for the oil and gas has soared in Japan because the bulk of its nuclear plants remain offline after a disaster at the Fukushima Dai-ichi nuclear plant following a devastating earthquake.