The Feasibility of Salinity Gradient Technology for Ireland: an Initial Case Study by the River Suir

Ciaran Murray, Dublin Institute of Technology
Jonathan Blackledge, Dublin Institute of Technology
Derek Kearney, Dublin Institute of Technology

Document Type Article

Journal on the Development and Applications of Oceanic Engineering, forthcoming, 2013, p.1-11


Under its EU obligations, Ireland has committed to generate 40% of its electricity demand from renewable means by 2020, and the objective of the minor dissertation from which this paper evolved, was to evaluate the feasibility of Salinity Gradient (SG) power technologies to contribute to this target. The country could be said to be currently over reliant on intermittent wind energy for its renewable quotient, and SG power could perhaps provide a local, continuous, base load power that would strengthen the security of national energy supply. At present, SG power, though the concept is long established, is a fledgling technology but one that is gaining international recognition and financially backed industry research and development. Ireland, with its long coastline in relation to its physical size and with many rivers draining into the surrounding seas, would seem to offer significant opportunities for harnessing the inherently extractable energy when fresh river and saline sea waters mix. As a background, a brief summary of the SG concept and the operational cycles of the most promising SG power generation technologies are outlined. Solid baseline data in terms of sea salinity concentration, temperature and river flow for the main rivers of Ireland was drawn together, and then applied to three,academically sourced, SG potential estimation models. These outcomes were then balanced with the practical, physical aspects of coastal estuaries and tidal movements in order to quantify the country’s SG potential. A specific case study, based on field measurements, for the River Suir in the south of the country showed the practical, geomorphological difficulties for SG power application in an Irish context. Overall, though there is a case to be made for consideration of SG technology for Ireland, it would appear that process technology efficiencies would have to be improved and natural, physical limitations overcome in order to make the proposition feasible in the long term.