This paper provides an overview of strategies and the results of grid-connection-related demonstrative projects of the New Energy and Industrial Technology Development Organization (NEDO). NEDO is Japan's largest public R&D management organization for promoting the development of advanced industrial, environmental, new energy and energy conservation technologies. One of the important objectives of NEDO's R&D is solving problems that arise when distributed and renewable resources are connected to power grids. These issues arise because the power output from most renewable energy resources fluctuates with weather conditions and connecting them to traditional power grids may create power quality issues. The authors introduce grid-connection-related national projects promoted by NEDO in which several energy storage technologies are applied to resolve those issues.