In order to complete a feasibility of a geothermal project it was necessary to first determine the existence of a geothermal resource, target depths, temperatures and geological conditions so as to determine a flow rate and infer a production capacity for the geothermal plant.
In 2007, GT Energy – in conjunction with Sandymark Construction and part funded by SEAI (Sustainable Energy Association of Ireland) – commenced its exploration programme of the Newcastle to Blackrock fault line.
Two deep geothermal boreholes were drilled and hot water bearing aquifer discovered at 1,337m. Temperature achieved of 46.2 °C at 1,337m, an attractive temperature gradient of 32.4°C per km and rock porosity of up to 22% in the lower rock formation of the boreholes showing great potential for targets in excess of 3km.
In April 2010, the ‘Seismic Acquisition Survey in the Southern Margin of the Dublin Basin’ project commenced to define the depth of the geothermal target reservoir formations in the deepest part of the Dublin Basin.
Based on the data gathered the approximate assumption can be made on the expected reservoir temperatures should reservoir target depths be present at 3,500m and 4,000m of 113.4°C and 130°C respectively. This temperature range implies the potential for geothermal electricity generation.
Following a positive feasibility GT Energy lodged a planning application with South Dublin County Council in October 2010 full planning permission was received in January 2011, just 3 months after lodgment. The project now awaits a government decision to extend the REFIT (renewable energy feed-in-tariff) mechanism to geothermal energy generation.