Announced December 17, 2008, Exxon Mobil's technology leadership in liquefied natural gas or LNG has resulted in an industry breakthrough in carrier design and size, enabling the more efficient transport of natural gas to markets throughout the world. The recent completion of the world's first Q-Max LNG carrier, named Mozah, marks a step change in LNG shipping by reducing transportation cost, while improving energy efficiency and reducing emissions. The innovative Q-Max ships carry up to 80 percent more cargo, yet require approximately 40 percent less energy per unit of cargo than conventional LNG carriers due to economies of scale and efficiency of the engines.
The large LNG ship technologies, developed in conjunction with joint venture partner Qatar Petroleum, include a number of industry breakthroughs and significant enhancements, including increased ship size, onboard reliquefaction units, slow-speed diesel engines, twin propellers and rudders, largest ship-board LNG tanks ever built, the latest in hull antifouling protection and improved fire-protection systems. The end result of these new generation ships is a 20-30 percent reduction in transportation cost.
For more than thirty years the size of LNG ships remained virtually unchanged with capacity of about 140,000 cubic meters. Qatar Petroleum and ExxonMobil's ship operators, hydrodynamicists, naval architects and structural engineers worked closely to develop and rigorously test the larger Q-Max cargo tank designs. Comprehensive evaluation of cargo sloshing was performed to prove that the larger systems were feasible and reliable. The resulting Q-Max carriers are longer than three football fields, tower twenty stories tall from keel to masthead and are equipped with the largest membrane containment tanks ever built. With a total capacity of up to 266,000 cubic meters, each ship carries enough natural gas to meet the energy needs of 70,000 U.S. homes for one year.
In addition to increasing the size of the ship, a major initiative was undertaken to design, test and implement the on-board reliquefaction plant that re-liquefies natural gas that is vaporized during transit, re-injecting it as liquid into the cargo tanks rather than using it as vaporized gas to power the tanker itself - allowing for delivery of nearly 100 percent of the cargo. This is particularly beneficial for the long-haul voyages from Qatar to Europe and the Americas. The on-board reliquefaction facilities created an opportunity to shift from steam boilers and turbines used for propulsion by conventional LNG ships to highly efficient slow-speed diesel engines. The Q-Max ships are equipped with two diesel engines driving twin propellers and rudders. This leads to more energy efficient, reliable and maneuverable ships, reducing fuel consumption by up to one-third.