Turning gas into electricity
Specialised machinery is required to convert methane gas into electricity. At the Gareth James Energy Park there are four 1 megawatt (MW) Jenbacher landfill gas to electricity generators. Jenbacher is an Austrian-based company that specialises in making industrial sized gas powered generators. They are expensive to purchase and install due to their specialised nature, and the need for foundations, pipework, transformers and electrical connections to make the generators fully functional.
Each Jenbacher generator produces a maximum output of just over 1MW, which is enough electricity to power over 1,000 New Zealand homes. The four generators are capable of producing enough electricity to power 4,000 homes. The Gareth James Energy Park supplies electricity via high voltage power lines into the national electricity grid at Waipara.
The Jenbacher generators are taken out of service periodically to carry out more significant repairs, including the replacement of worn parts. Jenbacher generators have a useful life of about 10 years.
The carbon dioxide emitted by these generators destroying the methane is biogenic in origin and not incremental. It would have been created by the decomposition of the organic waste even if not in the landfill.
We've put safety first
The generators are very complicated mechanical and electrical devices that require care when working around them. Electricity can be very dangerous, particularly when it involves high voltage. At the Kate Valley Landfill there are thorough systems to ensure people know all the risks associated with the operation of the generators, including training staff with very detailed and specific “Work Instructions” and “Risk Assessments”. These procedures are regularly reviewed and updated to ensure staff and visitor safety.