Is unconventional gas the answer to the world’s energy problems?


By a Newsnet reporter

We are beginning to hear more in the media about shale gas as advances in technology and the rise in the cost of fossil fuels make the unconventional gas industry a more realistic prospect. The term ‘unconventional gas’ is taken to mean gas which is trapped inside rock formations which were historically too deep or too difficult to extract the gas economically.

By a Newsnet reporter

We are beginning to hear more in the media about shale gas as advances in technology and the rise in the cost of fossil fuels make the unconventional gas industry a more realistic prospect. The term ‘unconventional gas’ is taken to mean gas which is trapped inside rock formations which were historically too deep or too difficult to extract the gas economically.

The two most common unconventional gases are shale gas and coalbed methane. These natural gases are fossil fuels produced over hundreds of thousands of years, they burn with lower emissions than other fossil fuels such as coal.

Shale is a hard rock formation found deep underground, it is brittle and non-permeable. Due to the nature of shale the extraction of the gas trapped within it often involves the injection, under high pressure, of a mixture of water, sand, and chemicals such as benzene and formaldehyde. The injection of this fluid aids the flow of gas.

Known as fracking, this is a long established technique but has not, up until now, been used so extensively on horizontal bores. The extraction of shale gas almost always involves fracking.

Coalbed Methane is extracted from coal seams. A variety of means of extraction are used but in most cases the coal seam needs to be ‘dewatered’ before gas extraction can take place. Dewatering involves the pumping out of water, which may have been present in the coal for hundreds of years. The action of pumping out this water is sometimes enough to start the gas flow, if it is not fracking may then be necessary.

America’s shale gas industry is well established and far more developed than it is in Europe. Unconventional gas accounts for 60% of marketed gas production in the USA.  20,000 wells have been drilled since the 1990s creating hundreds of thousands of jobs and providing lots of cheap gas.

There have been concerns in the US over environmental and health risks associated with unconventional gas extraction whether by means of fracking or not. In 2010 a documentary showed how the people of Dimmock, Pennsylvania could set fire to their taps due to the high concentrations of methane in the water system. Gas companies supplied residents with potable water or water purification kits.

Environmentalists, both in the USA and in Europe, worry about the possibility of toxic chemicals from fracking fluid finding their way into water systems and contaminating water for human or animal consumption. As much as 90% of fracking fluid remains in the seam or rock; it is not known what happens to this fluid.

The Dimock documentary also showed the very real danger of methane escaping and causing contamination. Methane is a very potent greenhouse gas. It is claimed by environmentalists that seepage of methane or fracking fluid (or both) could happen if any damage occurred to a bolthole.

A 2011 report commissioned by Cuadrilla, a company involved in unconventional gas extraction in Lancashire, found that the most likely cause of tremors measuring 1.5 on the Richter Scale was fracking.

A complication which is not immediately obvious is the effect of tremors on local businesses. The Rabobank banking group strongly opposed fracking development in Boxtel in the Netherlands because of concerns about disruption to their neighbouring data centre.

While coalbed methane extraction does not always require the use of fracking, environmentalists point out that coal seams tend to be nearer the surface than shale and are therefore closer to aquifers and groundwater, so may logically carry increased risk of contamination. There is also the added complication of the disposal of dewatering fluid.

The International Energy Agency counter that the risks can be managed in order to protect the environment at a relatively low extra cost. They say that properly concreted wells and shafts do not leak, that venting and flaring could take care of methane emissions and that the effects of tremors could be contained by careful monitoring. The IEA believes that such measures would add around 7% to the cost of the average shale gas well.  They do not quantify the environmental impact of the proposed measures.

While it is often shale gas which hits the headlines, in the UK reserves of coalbed methane gas are potentially much greater. The British Geographical Survey estimates the total reserves to be around 2,900 billion cubic metres, though how much of that is recoverable is uncertain.

In Scotland six areas have been licensed for unconventional gas exploration. Two of these have fairly advances coalbed methane projects.

The first is at Airth, near Stirling, where an Australian company named Dart Energy, (which is headquartered in Singapore), has a trade deal with Scottish and Southern Energy which will see it supply enough electricity to power 500 homes.

The second is in Dumfries and Galloway at Canonbie. The licences for “the injection of fracking fluids into groundwater” were originally awarded to Greenpark Energy but have since been acquired by Dart Energy.

Dart Energy has also taken over the smaller Scottish firm Composite Energy acquiring exploratory drill sites in Falkirk, Stirling, Clackmannanshire and Fife.

The Shieldhill and California Community Council have lodged objections to a current planning application for development of Coalbed Methane production at Letham Moss in Falkirk. They claim that the development would “jeapordise the health, quality of life and environment for future generations”, contrary to Falkirk Council’s Local Plan.

Mining in this particular area is shallow mining and this, they say, increases the risk of groundwater contamination. In support of their objections they cite numerous reports from the USA of “cases of illegal dumping of wastewater” endangering animal and human health. Cases have been reported where farm and domestic animals have died after consuming contaminated water. They also cite evidence produced by the National Oceanic and Atmospheric Administration (USA) showing higher than predicted levels of methane gas in the air near an unconventional gas extraction site in Denver. In some samples the levels were twice previous estimates. The NOAA also found evidence that “gas operations were leaking highly toxic and carcinogenic benzene into the air”

Falkirk Council have recently become overall winners in the Scottish Government’s Quality Planning Awards 2012 for their Greenspace Initiative. The community council suggest that the development of CBM extraction would “undermine this tremendous achievement and be several steps backward”. Not only have they urged the council to reject the application, they have also suggested a moratorium on CBM extraction  and that a Public Hearing be arranged to discuss an environmental impact and transport assessment. They point out that outright bans or moratorium on shale gas extraction are presently in place in France, Denmark, Germany, Bulgaria, Romania, the Czech Republic and the Netherlands.

The International Energy Agency says that global gas production could increase by 50% by 2035 with unconventional gas sources making up two thirds of that increase.