This paper discusses the issues of reliquefaction of natural gas vapors on the Q-Flex type LNG tankers. DRL gas carrier power plant has been presented. The principle of operation of a BOG reliquefaction plant has been described. An energy analysis referring to nominal operational conditions has been performed. DRL LNG carrier’s power plant load at laden voyage has been estimated. The results have been confronted with the values typical for conventional LNG carriers. General conclusions on the size of the Q-Flex LNG tanker’s power plant have been drawn.