LIQUEFIED NATURAL GAS

Liquefied Natural Gas



Liquefied Natural Gas

Introduction

Economic development and global population rise have increased demand for energy resources, and there are fears that available resources are becoming finite. The use of natural gas for power generation is a recent phenomenon, emerging during the 1980s and 1990s. It is strongly linked with the development of stationary gas turbines for power generation, and particularly with the combined cycle gas turbine configuration. The latter became particularly attractive in the liberalized electricity markets which were developing at the same time in many parts of the world (Field, 2007). The US and Japan were the first two countries to use gas extensively for power generation, the latter using LNG imports. The use of natural gas for power generation is predicted to grow over the medium term but such predictions need to be tempered by the fact that the price of gas is beginning to rise dramatically in some parts of the world

Liquefied Natural Gas

LNG is the acronym for liquefied natural gas. Methane (natural gas), along with several other gasses, is considered a greenhouse gas. The most common greenhouse gas is water vapor. However, concentrations of water vapour vary around the world as a function of climate. Yet levels of water vapour are many orders of magnitude above those of carbon dioxide, methane, nitrous oxide, ozone, and other trace gasses that are considered greenhouse gasses (Wells, 2003).

Liquefying methane is a common method of preparing it for transportation. It is liquefied by cooling it to negative 260 degrees Fahrenheit. Methane has become a very common energy source and is considered a clean-burning fossil fuel. One molecule of methane combusted with two molecules of oxygen will produce one molecule of carbon dioxide and two molecules of water along with the associated heat of combustion. Methane is also considered a greenhouse gas, although it is found at fairly low concentrations at 0.00017 percent. By comparison, carbon dioxide is more than 200 times more prevalent, and water vapor is tens of thousands times more prevalent (Romm, 2004).

Logistics of Gas Supply

The key to the future of natural gas lies in how that gas is to be supplied to the burgeoning markets across the globe. The traditional way to move natural gas is through a pipeline system. Such systems resemble electricity transmission systems with gas generation, transmission and distribution systems. However they are much less flexible than their electrical counterpart. Gas transmission networks operate most economically at full capacity so it is necessary to include some storage capacity on a system in order to cope with the peaks and troughs of gas demand. The major global pipeline networks today are located in North America and Europe (Field, 2007). The second means of moving natural gas is as liquefied natural gas (LNG). This can be shipped by tanker and can be transferred across the globe without the need for a pipeline. The movement of natural gas, either by pipeline or as LNG, follows a pattern today in which the highly developed economies ...