This document summarizes a report by the World Energy Council on integrating variable renewable energy sources like wind and solar into electricity systems. It finds that while renewables now make up 27.7% of global power capacity and their costs are declining, integrating their variable output poses technical and economic challenges for grid operations. The report examines case studies from 32 countries to identify lessons learned and solutions. It recommends policies like market reforms and capacity markets, along with technologies like improved forecasting, flexible generation, demand response, energy storage, and transmission upgrades to help renewable energy maintain growth while maintaining grid reliability.