Coal Seam Gas (CSG) is natural gas found in coal deposits in Australia. The coal and gas are formed from plant matter under pressure over many millions of years. Coal Seam Gas in Australia is used in the same way as any other form of natural gas for cooking and heating as well as in industrial processes and electricity generation. Coal seam gas in Australia collects in underground coal seams by bonding to the surface of coal particles. The coal seams are generally filled with water and it is the pressure of the water that keeps the gas as a thin film on the surface of the coal (the technical term for this is ‘adsorption’).The coal seams generally contain more brackish (salty) groundwater than aquifers that are usually used for agriculture.
Underground, CSG is typically attached by adsorption to the coal matrix, and is held in the coal underground by the pressure of formation water in the coal cleats and fractures. The level of gas that can be produced from a coal bed depends on the thickness of the coal, gas content, permeability and the depth of the coal seam. In high quality CSG deposits the cleats or fractures in the coal bed are permeable enough to allow gas and water to flow freely through them. Coal seams that can produce CSG economically are usually 200 to 1,000 metres below the surface.
In Australia, CSG is plentiful. Coal Seam Gas (CSG) is methane gas found in coal seams. Often referred to as “unconventional Gas”, CSG should not be confused with Liquid Natural Gas (LNG) which is also known as “conventional gas”. CSG is a newer resource extracted from coal deposits that are too deep to mine economically. The methane lies in pores and ‘cleats’ in the coal seams and is trapped there by water. When burnt, methane produces about 40% less greenhouse gas than coal. Un-burnt it is at least 20 times more polluting than carbon dioxide (CO2). The process of removing methane from a coal seam sees a large amount leaking into the atmosphere, adding significantly to greenhouse pollution.
Coal seam gas (CSG) in Australia is an odorless, colorless natural gas created over millions of years as a by-product while organic matter is turned into coal. This gas, mainly comprising methane, is trapped on the surface of the coal. Australia has sizeable quantities of this resource, mainly in Queensland and NSW. Although it is not currently widely used throughout the country, there is a lot of research looking at this method’s potential to contribute to Australia’s energy supply. Queensland is the country’s largest consumer of CSG, comprising more than 70% of the state’s gas supplies.
As coal is formed, methane, carbon dioxide and water are generated. While most of these gases and water escape naturally, some of it is trapped in the coal seam. The gas is extracted through the removal of the water which is contained within the coal seams. When this water is released, the gas is also discharged. Just like with other gases, Coal seam gas in Australia can be used to drive turbines and create electricity. There are several advantages from using coal seam gas to generate electricity:
• CSG is one of the cleanest of fossil fuels
• It is relatively inexpensive
• Its production creates water as a by-product