Numerous developing and emerging countries have ambitious plans for the development of renewable generation. Other countries show interest in renewable generation but corresponding plans are pending due to concerns relating to the consequences of fluctuating electricity generation. In both cases, the impact of renewable generation on system reliability and system security needs to be analysed in order to assess related risks and to propose mitigation measures for ensuring a secure and reliability power system operation in the presence of large penetration of renewable generation. The focus of this report is to provide an overview about the most relevant aspects relating to system reliability and system security, describe the most relevant influential factors and to propose methodologies for studying the impact of renewable generation on system reliability and system security.