South Korea is almost 100 percent dependent on energy imports to fuel its massive industry. A huge chunk of that is tanker-delivered liquified natural gas, and the proportion is only expected to rise:

At the core of the Vladivostok-Seoul gas pipeline is South Korea's almost unprecedented dependence on imports to cover its energy needs – the rate stands at 98-99 percent for quite some time already. South Korea's traditional means of generating energy largely boiled down to nuclear power and LNG, yet after the 2011 Fukushima catastrophe nuclear is about to be gradually removed from the national energy matrix.

But the problem is LNG is much more expensive than pipeline gas:

Korea's LNG import capacities are undoubtedly spectacular, as the nation's 4 LNG terminals can process up to 120 BCm per annum, double of South Korea's actual natural gas needs. Yet if one is to compare LNG imports to South Korea and Gazprom's exports to Europe, it becomes evident that Seoul has been overpaying massively.