This paper provides a decision support tool (DST) to analyze and evaluate the project value of offshore wind energy projects within the framework of project finance. The DST is based on a discounted cash-flow model in combination with a Monte Carlo simulation (MCS) to measure project risks and manage these risks. To consider the special requirements of debt capital providers in this context, key figures like the debt service cover ratio (DSCR) are calculated. The DST is realized in Excel/VBA with the Excel Add-In Oracle Crystal Ball. An offshore wind park example in the German North Sea is simulated to validate the underlying simulation model and the DST.