Renewable energy generations, especially wind power and solar PV generations, are, at this stage, among the most effective technologies in generating electricity from renewable energy resources. There are already large number of wind farms and solar PV farms connected to the high voltage transmission grid worldwide. Distributed generation based on renewable energy resources provides another feasible solution in promoting emission reductions at distribution level. Given all these increasing penetrations of renewable energy based generation sources, however, the renewable sources are intermittent in nature and have introduced various challenges to power system operations and planning. As such many of the large scale renewable energy farms are running at low capacity factors. This special issue provides a timely overview of methodologies of handling the renewable generation grid connection issues aiming at enabling more renewable energy utilization as well as Greenhouse Gas (GHG) emission reductions. This special issue accepted 11 papers covering the recent research findings in renewable energy grid connection related areas. These papers covered a comprehensive range from primary energy to policy studies.