Boost to UK geothermal energy prospects

February 24, 2010, Newcastle University

( -- Geothermal energy in the UK is a step closer to reality after exploratory drilling by experts at Newcastle University revealed record levels of permeability in granite.

Research led by Professor Paul Younger, from the Sir Joseph Swan Institute for Energy Research at Newcastle University, has revealed the highest permeability ever recorded for a granite anywhere in the world - in the centre of Weardale, County Durham.

The team were investigating potential sources of , which is becoming increasingly popular in the search for low-carbon energy resources.

Granite can be particularly useful as it is often rich in radioactive elements that generate heat as they decay but permeability is also important and until now granite was believed to be one of the most impermeable rocks.

“Hydrogeologists have traditionally viewed granite as poorly permeable, and this has led to a bit of a “counsel of despair” over the chances of finding decent permeability in granite,” explains Professor Younger, whose research is published today in the Quarterly Journal of Engineering Geology and Hydrogeology.

“We decided to challenge that pessimistic assumption, to see if we could find permeability at depth. And, eureka! we found it. As far as we can tell, the highest permeability ever recorded for a granite anywhere in the world.

The results were obtained by pumping naturally-occurring saline groundwater from an exploratory and monitoring the change in water levels. A permeability of almost 200 darcies - a unit of permeability - was recorded.

This is far higher than most prolific oil and gas reservoirs, and on a par with water wells in the Chalk that supplies London. The Newcastle team believe the find is not unique to the Weardale granite, as there are similar granites worldwide which may display equally high levels of permeability.

“This is great news for geothermal energy because high natural permeability means that time and money won’t need to be sunk into artificially developing permeability by means of hydraulic stimulation - a costly and uncertain business,” says Professor Younger.

However, the research also suggests that caution needs to be taken when selecting sites for nuclear waste disposal.

Granite is a popular rock in which to site repositories, and the higher than expected of the rock suggests that safety estimates previously made may have to be reconsidered.

Although repositories will obviously be located in areas where there is no large-scale faulting, more care will have to be taken to ensure that excavations will not enter ground that is more permeable than expected.

"The discovery that granite can in places be as permeable as the Chalk Aquifer is a little disquieting for repository construction in granite," says Professor Younger.

"If these structures are avoided, it ought to be possible to construct successful repositories in granite. However, it will require more detailed geological mapping than might otherwise have been undertaken - which is not entirely bad news for us geologists of course!"

Explore further: 1,000m underground central heating system planned

Related Stories

Probing Question: Could your kitchen counters be radioactive?

October 2, 2008

Verde Butterfly. Black Galaxy. Kashmir Gold. If you’ve remodeled your kitchen in the last decade, chances are you encountered one of the 1,600 varieties of granite imported into the United States from 64 different countries. ...

CO2 storage in coal can be predicted better

April 13, 2007

CO2 storage in the ground is being considered increasingly more often in order to realise the climate and energy objectives. Dutch researcher Saikat Mazumder made it possible to better predict routes of the 'underground highways' ...

New map hints at Venus's wet, volcanic past (w/ Video)

July 14, 2009

( -- Venus Express has charted the first map of Venus's southern hemisphere at infrared wavelengths. The new map hints that our neighbouring world may once have been more Earth-like, with both, a plate tectonics ...

Recommended for you

Weather anomalies accelerate the melting of sea ice

January 16, 2018

In the winter of 2015/16, something happened that had never before been seen on this scale: at the end of December, temperatures rose above zero degrees Celsius for several days in parts of the Arctic. Temperatures of up ...


Adjust slider to filter visible comments by rank

Display comments: newest first

1 / 5 (2) Feb 25, 2010
And what about the radioactivity of the water?

How are we going to stop people glowing in the dark after a sip from the run-off water from the radioactive source?
not rated yet Feb 25, 2010
Heat exchangers, Loodt. Just as it is done in nuclear reactors.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.