BHP has teamed with Energy Developments Limited and Lend Lease Infrasb"Ucture, to establish an electrical power generation facility that utilizes methane produced as a by-product of mining at BHP's Appin and Tower coal mines in southern New South Wales. In what is believed to be a world fIrst, Energy Developments Limited has developed technology which will capture not only the drained methane, but also a portion of that which is present in the ventilation air, reducing BHP Collieries Division's greenhouse emissions by approximately 50 percent. The methane gas is converted to electricity using state-ofthe- art lean burn gas engine technology. Construction and installation of two plants, comprising a series of one megawatt gas engines, commenced in July 1995 Full capacity was achieved on 5 September 1996. The combined output is 94 megawatts of electrical power. Gas supply tends to vary with geological conditions and mining performance. An advantage of the multi-engine concept is that engines are brought on-line as required to match the available gas supply, thus optimising the total efficiency of the plants. The gas engines are capable of consuming a total of 161,262 tonnes of methane per annum (93,712 tonnes from Appin and 67,550 tonnes from Tower). The electricity generated at the plants will be supplied to the local distributor, Integral Energy, and be sufficient for up to 60,000 homes.