Moranbah North Power Station, Australia
Moranbah North is a 45MW power plant located in Central Queensland at the Anglo Coal's Moranbah North mine. The plant generates electricity from methane-rich gas that is released during underground mining operations. The plant, owned and operated by Energy Development (EDL), was constructed at a cost of $60m. It began operations in late 2008 and was officially opened in September 2009.
The plant is the third of EDL's waste coal mine gas (WCMG) projects in Australia. In Central Queensland, EDL operates a 32MW German Creek Power Project. It also operates a 97MW Appin Tower Power Project near Wollongong in New South Wales.
The Moranbah North Power plant was constructed on a turnkey basis under a separate contract with Clarke Energy. Clarke Energy was responsible for the overall design, balance of the plant, and engineering activities. Construction was completed within 14 months, seven months prior to schedule. The first power was generated within 11 months.
The plant comprises of 15 3MW J620 Jenbacher gas engines, a complete balance of plant, gas conditioning units, 66KV electrical distribution and a state-of-the-art control room. The gas engines certified by GE Energy's ecomagination, were installed by Clarke Energy as part of the turnkey contract.
The gas engines have an annual capacity of producing 350GW electricity, sufficient to power 48,000 households.
They are incorporated into special purpose enclosures to ensure that no derate takes place until 35% ambient temperature is achieved. The control system of the plant consisting of a waste coal gas ring main is utilised with gas blowers to control the suction and discharge pressure from the mine.
The plant operates on waste coal methane gas that has a methane level of 50% to 90%. The gas engines use a combined heat and power (CHP) technology that reduces operational expenses substantially for the operator. Despite low heating value, fluctuations in gas supply and difficult ambient conditions, the plant achieves an overall electrical efficiency of up to 40%.
The plant will reduce up to 1.3mt of equivalent carbon dioxide ( CO²e) every year. Environmental benefits arising from the plant will be equivalent to taking 330,000 cars off the road each year. When compared to CO2e, WCMG, a natural gas released during mining, has 21 times more global warming potential of CO². The plant has been accredited under the New South Wales Greenhouse Abatement Scheme. The plant also improves safety conditions as it removes the potentially hazardous gas.
The plant sells most of its production to the national grid via a 66KV electrical distribution network. Gas generators produce electricity at 11KV, which is increased to 66KV before it is distributed onto the national grid. To connect the plant with the national grid, 5km of interconnecting high voltage (HV) transmission lines are used. The HV lines were installed by Clarke Energy as part of the turnkey contract.
The national grid network has the capacity of carrying electricity from as low as 3.3KV to as high as 275KV.
The National Electricity Market (NEM) operations in 1998 and has been connecting Queensland, New South Wales, Tasmania, Victoria and South Australia. It operates one of the longest interconnected power systems in the world with an end-to-end distance of approximately 5,000km. The market annually provides A$10bn worth of electricity to nearly 8 million consumers.
Moranbah North mine
The plant takes WCMG released from the Moranbah North Mine. Moranbah North is an underground mine located 18km north of the Moranbah town in the Queensland's Bowen basin. The mine produces high-quality coking coal, which is primarily used for the steel industry.