Over the period of one decade, Germanischer Lloyd (GL) has developed and applied risk analysis procedures to assess the collision risks for offshore wind energy installations (WEI). The revised GL guideline focuses on the identification and assessment of collision risks between ships and wind energy installations. Other risks (e.g. collision risks with air traffic) are discussed, but not in the same depth as ship-WEI collisions. The basic approach is a pragmatic mix of formal procedure and empirical data required for model applications. Basic assumptions were harmonized in 2004 between major providers of such risk analyses for offshore WEIs in Europe. The basic assumptions and their underlying reasoning are described. The guideline is an important contribution to ensure comparability, repeatability and transparency of such risk analysis. The guideline addresses the main factors influencing collision probability and damage extent, including risk control measures. Concepts are illustrated by applications taken from existing or planned North Sea installations. While illustrative examples are all taken from the North Sea, the procedure has been applied more widely.
Modern safety engineering offers assorted methods to assess complex systems and their risk for man and environment. The main task is to apply these proven methods appropriately within risk analyses for offshore wind farms (OWF). Germanischer Lloyd (GL) has developed a guideline for this purpose (GL, 2010). The assessment of accidents ends with the quantification of spilled pollutants, harm to property or persons. Subsequent damage due to spilled substances can be investigated in environmental risk or impact analyses and is not subject of the GL guideline. The risk analysis is a documented approach to ensure the retraceability of lines of arguments and calculations. An OWF risk analysis should assert verifiably − whether a planned OWF fulfils the safety requirements,