Energy from abandoned oil reserves
The team of geologists and biologists have been studying the little-understood process by which naturally-occurring microbes deep below the ground convert oil and coal to natural gas, over many millions of years.
They believe that this process could be speeded up, possibly by simply feeding the microbes with nutrients like vitamins and minerals down boreholes.
If the theory works in practice, oil and possibly coal reserves that are currently uneconomic to extract from the ground could be converted to sources of natural gas, otherwise known as methane.
The findings of the research, led by Professor Ian Head and Dr Martin Jones, of Newcastle University, and Professor Steve Larter, who works at both Newcastle University and Calgary University in Canada, are published online this week by the leading scientific journal, Nature (advance online publication)
It was already known that most of the world's oil reserves are affected by microbes, to some extent. This reduces the value of the oil by making it thicker and more costly to extract. Some reserves have been left in the ground because it would be uneconomic to work them.
Little was known about the process by which the microbes 'biodegraded' the oil. By studying the actions of the microbes in laboratory tests, over a two year period, the team discovered that the process was started by a species of anaerobic bacteria called syntrophus, which digested the oil and produced a mixture of ethanoic acid - or vinegar - and hydrogen gas. However, another type of microbe, methanogens, which belongs to the archaea family, was then combining the liberated hydrogen with carbon dioxide and turning it into methane.
The scientists now hope that the discovery can be applied commercially to oilfields, such as the huge tar sand deposits in Canada - and possibly coalfields, like the former mining areas around Newcastle, in North East England.
Most countries are currently trying to reduce their reliance of fossil fuels, like oil, coal and gas, in a bid to tackle climate change. Professor Head, of the School of Civil Engineering and Geosciences at Newcastle University, points out that burning methane as a fuel, for example in power stations, produces about ten per cent less greenhouse gases, such as carbon dioxide, than burning coal or oil.
Professor Head added that for the foreseeable future, the UK and other countries will depend on fossil fuels for at least some of their energy needs, while large scale alternative energy sources are developed.
'Clearly any development of fossil fuel resources needs to be coupled with appropriate technologies to mitigate their effects on climatically active emissions', he added.
Talking about the research published in Nature, Professor Head said: 'There are potentially major economic implications to these findings, since a proportion of the trillions of barrels of oil, currently regarded as unworkable, could in theory be converted into methane, or natural gas.'
'In North East England, similar processes may occur in abandoned coal mines, opening the door to a possible means for recovery of the region's extensive abandoned energy resources as clean-burning methane.'
published on: 12th December 2007