Abandoned Mine Methane Gas (AMM)
Abandoned mine methane (AMM) can be recovered from disused coal mines. Abandoned mine methane (AMM) projects produce energy (thermal and electrical) with the added bonus of reducing atmospheric emissions of methane. Methane is a potent greenhouse gas and huge amounts of methane will escape from the mine for years to come following closure. Sealed abandoned mines offer an excellent opportunity for methane extraction, especially if recovery takes place quickly after the mines closure. Abandoned mine methane provides a good source of medium to high quality methane. Mine gas from abandoned mines typically contains no oxygen, and its composition changes very slowly. The methane content can range from 60-80%.
Even after coal mines are shut down, coal mine gas continues to be released. The composition of abandoned mine methane gas presents no technical difficulties for combustion in gas engines. The thermal energy can be used for heating purposes fed into a district heating scheme.
Advantages
- Alternative disposal of a problem gas whilst simultaneously harnessing it as an energy source
- Extreme profitability with overall efficiency of up to 90% in the case of combined heat and power, and 43.4% in the case of power generation alone.
- Smooth operation despite fluctuations in gas pressure, methane content and impurities in the gas.
- Depending on the gas composition, full output down to the lowest calorific values with 25% methane content
- Avoid the liberation of methane into the atmosphere which has 21 times the global warming potential of CO2
Competence
The first Jenbacher systems using coal mine gas were installed in the UK and Germany in the mid 1980s. Clarke Energy has installed over 237 MW of generation capacity on the different forms of coal gas. Clarke Energy’s Australian operation is one of the leading centres in the world for the development of coal gas sites, accounting for over 146MW of this total. These plants generate over 1.5 million MWh of electricity per year – enough to supply about 430,000 EU homes.
Generating this amount of electrical power with coal mine gas could save approximately 367 million cubic metres of natural gas a year. In addition, using coal mine gas in GE Jenbacher engines, can reduce the release of methane into the atmosphere by about 85% compared to venting the gas, which corresponds to CO2 savings of 30-40,000 tonnes per year. Due to their cost effectiveness, high output and measurable benefits to the environment, GE Jenbacher coal mine gas engines have been certified as GE ‘Ecomagination’ products by an independent agency. Ecomagination is a GE commitment (www.ge.com/ecomagination) to use and develop new technologies to help customers around the world meet escalating environmental challenges.
