Powerlines report published

Opponents of the proposed powerline across the North East and power company EirGrid are studying the independent 'Study on the Comparative Merits of Overhead Electricity Transmission Lines Versus Underground Cables' published on Wednesday by the Communications and Natural Resources Minister, Eamonn Ryan. The Study was initiated in February of this year following calls from deputies from all sides of the house, particularly those members of the Joint Oireachtas Committee on Communications, Energy and Natural Resources for an independent study to consider the issues involved with both types of transmission infrastructure. The issue had become controversial following the proposal by EirGrid to develop a 400 kV powerline on pylons from Meath to Cavan, and from there to Tyrone. The study was conducted by international consultants Ecofys and Golder Associates, a global group specialising in ground engineering and environmental services, in partnership with an expert in underground cable technology. A total of 522 submissions were received and reviewed by the consultants undertaking the report. Current international practice and two hypothetical case studies with route lengths of 100 km and 50 km were examined. The study examined electricity transmission technoloies, comparisons of technical and economic characteristics, environmental and health impacts, policy implications and costs. The study was not project specific and was designed to inform decisions on transmission infrastructure generally. The key findings of the study are as follows: - Increasing pressure internationally has become an important driver for underground cables as an alternative. The technology for underground cables at high voltages is continuing to develop. - International experience of laying such cables over long distances is limited and the majority of existing projects do not represent transmission connections in conventional networks such as we have in Ireland - Underground cables can be expected to have forced outage rates which are at least 10 times greater than that of overhead lines. - Underground cables are therefore severely limited in terms of transmission adequacy and are not equivalent to overhead lines in terms of security of electricity supply - Work undertaken on the two case studies suggest that the capital cost of constructing underground cables would be approximately 5 times greater than the cost of overhead lines and 3 times the lifecycle costs - Exposure to magnetic fields may be higher directly above an underground cable than under overhead lines. Additional measures can reduce the magnetic field for both options. - Ireland designs and operates transmission assets in line with World Health Organisation (WHO) guidelines. In Ireland magnetic field exposure directly under a transmission line is generally 80-90% lower than the maximum levels recommended in the WHO guidelines. - Both overhead and underground options have environmental impacts. Minister Ryan said: "The Study demonstrates that decisions on these kinds of projects need to take a wide range of complex technical, economic, environmental and other considerations into account. My Department will now arrange for the consultants to present their findings to the Joint Oireachtas Committee on Communications, Energy and Natural Resources. "The Study was commissioned in order to provde an accurate and independent set of facts regarding the technical, environmental, health and cost implications of overhead lines relative to underground cables. This report provides these facts. I am confident that this Study will assist all interested parties in current and future transmission projects". The full report can be viewed at: http://www.dcmnr.gov.ie/Energy/Independent+Study+on+Electricity+Transmission+Infrastructure.htm