Europe's natural gas prices would have to double to lure enough cargoes from the global market to replace Russian supplies, adding to the challenges of decreasing the region's dependence on its neighbor.

Benchmark U.K. prices would need to rise 128 percent to attract liquefied natural gas if Europe had to replace all its Russian fuel for two summer months, according to Energy Aspects Ltd. in London. LNG, shipped by tanker from as far away as Australia, would be the main alternative to the regional pipelines filled by Russia.