For almost two decades Illawarra Coal has been capturing and utilising the methane gas which, for safety reasons, is drained from coal seams prior to mining.
The gas has been piped to gas engine power plants near the townships of Appin and Douglas Park since 1995, reducing the company's annual greenhouse gas emissions by 2.5 million tonnes and producing enough energy to power around 60,000 homes each year.
However, not all the methane associated with the coal seam is able to be drained and small percentages of methane are present in ventilation air which is exhausted from the underground operations.
To address this, BHP Billiton Illawarra Coal, in partnership with international emission control specialist MEGTEC Systems AB, established a pilot plant at its Appin site to trial the use of VOCSIDIZER technology to use methane in the ventilation air for electricity generation. The success of this pilot led to the establishment of WestVAMP.
WestVAMP converts low concentration methane to carbon dioxide and water vapour through an oxidation process. High efficiency heat exchangers recover the thermal energy to produce steam.
This steam is used to drive a conventional steam turbine - generating six megawatts of electricity.
Through the WestVAMP project, Illawarra Coal has been able to reduce its greenhouse gas emissions by 2.5 million tonnes.