Generating power from methane emissions

A CSIRO technology called VAMCAT (Ventilation Air Methane Catalytic Turbine) is poised to take a sizeable bite out of methane emissions with a greenhouse effect equivalent to more than 237 million tonnes of carbon dioxide.

CSIRO and the Australian Greenhouse Office, together with China's Shanghai Jiaotong University and Huainan Coal Mining Group, will construct a pilot-scale demonstration unit at a coal mine in China. The low-heating value gas turbine will be powered by about 1% methane in ventilation air. It will generate green power while also consuming the mine's fugitive methane, which is 23 times more potent than carbon dioxide as a greenhouse gas over a 100-year time frame.

The project is being conducted under the Australian Government's Bilateral Climate Change Partnerships Program along with support from an Australia-China special fund grant under the Australian Government International Science Linkage Program. The initial investigation of catalytic combustion performance was supported by a grant from the Australian Coal Association Research Program (ACARP).

The project is being led by Dr Shi Su from CSIRO Exploration and Mining.

"China is responsible for about 45% of total ventilation air methane emissions," Dr Su said.

"Although gas drainage efficiency in China has increased from 15% in 1998 to 26% in 2004, much of the captured gas is poor in quality. It is estimated that more than 70 to 80% of the drainage gas has a methane concentration of less than 30%, which cannot be used by conventional technologies. So while China is the largest source of mine methane emissions, it is also the largest potential market for technologies mitigating those emissions.

"Once the novel gas turbine technology is demonstrated at a coal mine, it will also have application in the mitigation and utilisation of methane from landfill, livestock and the combustibles in industrial offgas."

A prototype demonstration unit with a power output of 10 to 30 kW will first be demonstrated in the Chinese mine. Operational performance data and experience gained from this small unit will be used for the design of a second-generation turbine of at least 1 mW output.

Approximately 70% of all coal mining-related greenhouse gas emissions can be attributed to methane exhausted to the atmosphere. This is not only bad for the environment, but also a waste of an important energy source. VAMCAT has the potential to reduce these emissions while also providing a valuable source of clean, green energy.