Cost-Benefit Analysis using Probability Density Function for Lightning Protection of Offshore Wind Power Plants by Independent Lightning Towers

Abstract

Offshore wind power plants has gotten attention worldwide as one of key technology for future energy mix. Recent Japanese policy also promotes offshore wind power plants (OWPPS) on costal waters in the Sea of Japan. On the other hand, those areas are known by notorious winter lightning with upward lightning and large electric charge, that has caused catastrophic damages to onshore wind turbines in past. It is therefore needed stronger lightning risk management for offshore wind turbines than that for onshore. The authors proposed a lightning protection method using an independent lightning tower (ILT) and have stored experience by numerical calculations and small-scale model experiments. However, there still remain several uncertainties in the given data. This paper proposes a new method on CBA (cost-benefit analysis) regarding with the uncertainty. In the concrete, a probability density function, e.g. Gauss Function, is superimposed on quasi-quantitative data with several uncertainty given by experiment tests, which enable optimization of net benefit and objective and quantitative decision making for appropriate risk management even under uncertainty.