Climate change and extreme wind effects on transmission towers

Climate change poses a major threat to electricity power infrastructure due to expected increases in the magnitude and frequency of extreme storm events. This paper uses a methodology for assessment of the vulnerability of UK transmission tower infrastructure to such events, within a framework of performance-based engineering. The challenge of estimating future storm magnitudes is addressed by applying a change factor methodology to present-day wind speeds using information provided by the 2009 UK climate change projections. A Weibull distribution is employed to obtain wind speeds for storm events at different recurrence intervals. Wind loading on the structure and cables is then determined using Eurocodes, and the structure is analysed using pseudo-static finite-element analysis, considering material and geometrical non-linearity as well as linear and non-linear buckling effects. The outcome of the research is that, despite a significant projected increase in wind velocities due to climate change, the typical tower analysed in the study continues to perform satisfactorily at all hazard levels. If this performance can be demonstrated more generally across the UK transmission tower infrastructure network, then it is likely that the cause can be traced back to the high factor of safety applied in the original design of the towers.