Geothermal energy : settlement and water chemistry in Cork, Ireland

Detailed analysis of potential water chemistry and settlement issues associated with the installation of open-loop geothermal
systems is infrequently carried out. This has led to the failure of several previously installed systems. Chemical analysis of
water extracted from beneath the Cork docklands, Ireland has been performed by the authors in order to assess the suitability
of the area for the exploitation of open-loop geothermal energy. The possibility of settlement induced by pumping of
groundwater for open-loop systems has also been examined. Current market penetration of ground source heat pumps in
Ireland is discussed to illustrate the infancy of the technology in Ireland relative to other European countries and to highlight
the necessity of approaching the possible installation of such systems with the care required. Water extracted from beneath
the docklands shows that significant water chemistry issues exist. Laboratory and field tests confirm that optimal
concentration levels of several water chemistry characteristics are significantly exceeded; leading to the conclusion that open-loop
exploitation in the area may not be suitable. In addition, settlement induced by pumping of water could potentially lead
to a consolidation settlement in excess of 30 mm due primarily to the existence of highly compressible alluvium.