Geothermal Resource Map of Ireland

Name of Contractor: CSA Group, Conodate Geology, Cork Institute of Technology
Category: Public Good
Completion Date: July 2004

Introduction

This study was performed by the CSA Group in cooperation with Conodate Geology, Cork Institute of Technology and the Geological Survey of Ireland. The goals of the study were to:

Identify potential resources of geothermal energy in Ireland.
Create geothermal models of Ireland and gather the necessary thermal, geological, structural and hydrodynamic data to facilitate modelling. Produce a GIS-linked geothermal database and using the models, create a series of geothermal maps of Ireland.
Review the current status and utilisation of geothermal energy resources in Ireland.
Present recommendations on the future potential exploitation of the geothermal resource in Ireland in the context of International Best Practice.

Outputs

The study surveyed/compiled data on warm springs and groundwater temperature trends. In order to map the subsurface temperatures, all available borehole data in the Republic of Ireland were gathered. Temperature data from 19 mineral and oil exploration holes ranging in depth from 300m to 2,500m (deepest borehole Drumkeeran (No. 1), Co Leitrim) were retrieved from previously monitored boreholes. In addition to this, CSA surveyed 32 existing, open boreholes to obtain their temperature profiles. This survey examined holes ranging in depth from 40m – 810m (deepest borehole 01-541-03, Co. Galway). A preliminary review of data from Northern Ireland was also included.

All survey data were added to the existing temperature data compiled for earlier studies. These data are presented in the Final Report which can be accessed via the above website link. Geothermal maps have been produced for surface, 100m, 500m, 1,000m, 2,500m and 5,000m depths. The maps may be viewed using MapInfo software. In this way temperature plots may be examined with the accompanying geological data overlaid. Individual borehole data points with references may be interrogated.

The results of this review indicate that Ireland is particularly well suited for the utilization of ground source heat pumps, due to its temperate climate and rainfall levels that ensure good conductivity and year round rain-fall recharge.

There are abundant marine and surface water geothermal resources which could be exploited in Ireland, but they need some encouragement for their development. The two main areas of warm spring development are in the north Leinster and Mallow regions.

Considering the Republic of Ireland and Northern Ireland together, this review has indicated a regional increase in temperatures ranging from 17ºC – 19ºC in the south to 25ºC – 27ºC in the north at 500m depth. At 2,500m temperatures range from 28ºC – 45ºC to the south to 64ºC – 97ºC to the north. This indicates significant geothermal sources with the potential for commercial development. Definition of the exact profile and extent of the geothermal sources and quantification of the resources requires additional assessment in any area deemed to be of interest.