By Gina Maffey
 
Tapping into the Earth’s thermal stores to heat the home may not be an entirely new concept, but the British Geological Survey has been demonstrating the hidden potential of Glasgow’s old mine shafts to do just this.
 
Ground Source Heat Pumps (GSHPs) were first used back in 1834, and essentially work in a similar way to a boiler. However, where a boiler uses fuel to heat water the GSHP pumps water underground harnessing the heat naturally.
 
John Ludden, Executive Director of the British Geological Survey said: “It is the difference between the underground temperature and that at the surface that makes this process work and in countries where there are extremes, such as Canada and Sweden, this is a well proven process.
 
Although the government is committed to a target of 15 per cent of energy production coming from renewable sources by 2020, the UK is far behind the rest of the EU in using GSHP technology.
 
At present 50 per cent of our energy production goes on heating, and 54 per cent of that is on domestic heating, mainly using gas.
 
By using the existing mine workings beneath Glasgow, the British Geological Survey thinks there is the potential to provide 40 per cent of Glasgow’s space heating requirements.
 
The mine workings beneath Glasgow have been flooded since being abandoned and the water remains at a fairly constant temperature.
 
Warm water would be removed from the mines and passed through a heat pump to heat homes. After the heat had been extracted, cooler water would be returned to a lower level underground.
 
There is also the potential to reverse this system in the warmer months using cooler water to reduce temperatures, before returning warmed water underground; effectively turning the system into a reservoir.
 
This system has been in place on a small scale in Glasgow for the past 13 years, where 17 flats in the Shettleston area are heated using a GSHP connected to the mines.
 
Although the system is expensive to install in a single domestic home – approximately £10,000 - £15,000 – it works under an economies of scale principle making it cheaper for larger units such as schools and universities to use.