Only lowgrade heat can be expected from geothermal sources in Ireland.
Research is required to find sites to supply industrial and horticultural
heating needs.
Geothermal energy is the earth's natural heat.
Heat is transferred to the earth's surface by conduction
through rock and via convection in
moving fluids. Heat flow is highest in regions
of active tectonism and volcanics and lowest in
stable shield areas. Geothermal energy can be
used for (a) electricity production or (b) direct
heating applications. Geothermal energy available
on demand, unlike wind energy which is
only available when there is sufficient wind
speed.
Geothermal energy systems can be classified
into four categories:
The geographical extent of potential hot dry
rock systems is limited. The system involves a
temperature of over 200oC at a depth greater
than 3km (5-7km). Water is injected into the hot
rock through deep boreholes and the hot water
or steam returns up another borehole to be used
for electrical generation. This system does not
have potential in Ireland but experiments have
been conducted in Cornwall in the UK.
High enthalpy systems are associated with
active tectonic and volcanic areas. These are
water or vapour dominated systems. The temperature
of the source is over 200oC. These systems
are generally used for electricity generation.
They are not suitable for Ireland due to the
geological conditions in the country.
Low enthalpy systems are applicable for stable
geological areas e.g. North West Europe.
Suitably warm rocks occur at depths of up to
2km with temperatures up to 100oC. This system
is used for direct heating in, for example,
the Paris basin and in Southampton, England.
Applications include industrial and horticultural
heating. This system has potential in Ireland
but research is needed to locate suitable sources
of this geothermal heat.
Shallow geothermal energy uses geothermal
energy with a source temperature of about
10oC. The temperature is increased using heat
pumps. There are four main production configurations
currently in use in Ireland - horizontal
loops, vertical loop, groundwater and building
foundations. Current applications include space
heating in commercial buildings, private houses
and swimming pools. The most common configurations
use horizontal loops or the direct use
of aquifer water. There are 500-600 installations
in Ireland at present.
The status, needs and potential for future development
of the geothermal resource in Ireland
can be summarised as follows:
Low temperature geothermal using heat
pumps
Status at present hot dry rock system
high enthalpy systems
low enthalpy systems
shallow geothermal energy
Required to develop use of technology on a large scale
Potential of resource
Low enthalpy systems
Status at present
Required to develop use of technology on a large scale
Potential of resource
The Geothermal Association of Ireland was founded in 1997. It has over 30 members, with representation from academic institutes, energy management agencies, consultants and contractors. The association is the Irish representative on the European Geothermal Energy Council. The objectives of the Geothermal Association of Ireland are as follows:
The activities of the association include:
The secretary of the Geothermal Association of Ireland can be contacted
through: This is one of almost 50
chapters and articles in the 336-page large format book, Before the Wells
Run Dry. Copies of the book are available for £9.95 from Green Books. Continue to part E of Section 7: Power from the sun is accessible to all
Cork County Energy Agency,
Spa House,
Mallow,
Co. Cork.
Ph: +353.22.43610
Fax: +353.22.43678
e-mail: mallowre@eircom.net
