Adequacy assessment of generation capacity is a statistical measure of the ability of existing or planned generation plant to meet predicted levels of electrical demand. Complications arise in this calculation because at any point in time the exact level of capacity available is variable due to planned and forced outages. Planned outrages is a term used to describe the period during the year when a generation unit is required to be shut down for maintenance work to be carried out. The duration of this outrage is normally known and its timing can be chosen. Forced outages describe the random failure that can occur that lead to a unit being shut down for repair. Due to the random nature of forced outages, regardless of the level of capacity in a system, 100% reliability cannot be guaranteed. The goal of this work is to investigate generation adequacy assessment in an Irish context. In this thesis the literature review in the area that was undertaken is outlined. Details of how the information gathered by this process allowed for the development of the data sets used in the investigation of generation adequacy are discussed. One of the principle sources of the information used in this process was the Generation Adequacy Report (GAR) that is published by Eirgrid each year. The developed analytical and numerical methods were first applied to the IEEE reliabity test system and then extended to the Irish generation system. Another of the principle aims of the project is to investigate the inclusion of wind capacity into generation adequacy assessment. To achieve this, a series of wind capacity models have been developed using data sets that have been acquired from Met Eireann and wind capacity production data from several Airtricity wind farm. The methodology behind and the various results from applying these different models are detailed