by Claudi Santiago, President,
GE Energy Oil & Gas

For the power generating industry today, natural gas is a clean and therefore highly desirable energy source. Until recently, however, natural gas has not necessarily been available wherever needed, at the right price. The picture is changing rapidly as evolving technology improves the economies of transporting natural gas in liquified form – Liquified Natural Gas, or LNG.

LNG has been an important part of the energy equation in some regions, notably Asia, for decades, and received a flurry of attention in the United States during the energy crisis of the late 1970s. But for the most part, LNG has not played a significant role in the global energy picture until recently.

Changing economics in the gas market also work in favour of LNG. With the latest technology, LNG can be brought into major markets at about $3.50 per million Btu. With today's gas prices above $4, it’s easy to understand the growing interest in LNG.

Worldwide expansion in gas compression
Not so long ago, LNG was not considered a strategic energy source. Expanding infrastructure and improving economics is changing that. Today, LNG trade represents 25% of international gas movements, and it competes successfully with other sources of energy. Global demand is increasing, especially in the U.S. and in Europe, and to meet the demand many world-scale LNG projects are under development.

During the 1990s, six new projects started up and many existing facilities were expanded. Today, new plants are being constructed in Egypt, Australia, Equatorial Guinea, Indonesia, Norway and Russia. Plants are being expanded in Trinidad, Oman and Nigeria, and new projects are proposed in Nigeria, Angola, Qatar and other locations.

As a result, global LNG capacity has grown by 60 million tons per year, an increase that represents more than 50% of existing global base-load capacity. At the same time over 60 LNG ships are on order or under construction, a 50% increase, and a number of new LNG receiving terminals are under construction.

If all of these projects come to fruition, LNG production capacity could well double by the end of the decade.

Bigger and bigger means better and better
To compete more effectively in global markets, LNG plant owners are looking to reduce costs through economies of scale. GE Energy Oil & Gas is part of the solution, with new equipment that makes possible dramatically larger train capacity.

Our focus is on the heart of the liquefaction process, the main refrigerant turbo compressors. During the late 1970s and into the 1980s, the LNG industry moved away from steam turbine-driven liquefaction trains to gas turbine drivers, with single train outputs between 2.1 to 2.7 million tons per year. A typical gas turbine for these applications was the GE Frame 5 machine.

In the early 1990s, Malaysia LNG planned a major expansion, and looked at the concept of using fewer, larger machines for the same refrigerant power. GE responded with the Frame 7EA, an 86-megawatt machine; and the smaller Frame 6B, a 43.5-megawatt machine. These gas turbines were adapted and successfully integrated with large compressors.

Other projects followed for large gas turbine-driven compression trains, among them Bonny Island trains 1, 2 and 3 in Nigeria, and Oman LNG trains 1 and 2. The Oman project achieved 3.3 million tons of LNG per train, at that time the largest train capacity in the world.

In the late 1990s, to move to even greater tonnage the industry focused on the propane refrigeration cycle. The more powerful and complex propane compressors required greater driving power, which the Frame 7EA gas turbine was able to provide.

By 2000, single-train capacities of up to 5 million tons a year were not uncommon. But within a short time breakthrough technology set even higher levels of production.

Speed variation for these machines in mechanical drive service today is set at 96-102% of 3000 rpm, the nominal speed. 3000 rpm offers significant benefits when used to drive an LNG train, especially in the propane cycle, since it eases the aerodynamics while the volume flows increase, delivering a significant boost in plant production.

Once again, the world’s largest trains for LNG production – from GE Energy
As a result of this on-going development work, GE Energy was awarded a contract to supply three turbo compressor trains for main refrigerant duty in the Qatargas II LNG Expansion Project. Qatargas II is the world's largest LNG project, and the GE-built trains will also be the world’s largest.

Each Qatargas II liquefaction train will be rated for an annual capacity of approximately 7.8 million tons. GE Energy is supplying three Frame 9E gas turbine-driven compression strings with low emissions capability. Shipments of the units will begin in November of 2005; plant startup is planned for the winter of 2007.

The large centrifugal compressors will be manufactured, assembled and tested at the GE Energy Oil & Gas plants in Florence and Massa, Italy, using new manufacturing and testing capabilities. For example, impellers will be machined from single forgings, eliminating the need for welding. Testing capacity at Massa has been raised to 130 megawatts.

This project is another milestone in the development of the global LNG industry, and demonstrates the expanding capabilities of GE Energy's Oil & Gas business. By creating new economies of scale it enhances the competitive position of LNG in world energy markets, and ensures the availability of clean natural gas wherever it is needed.