This report describes the current state of the art with variable generation integration. It focuses on the United States but provides a few international examples where relevant. The report is predominantly based on an extensive literature review with input from General Electric (GE) and PJM. It includes sections on energy market scheduling, the visibility of distributed generation to grid operators, energy imbalances, reserves, contingency reserves, wind and solar forecasting, consideration of variable generation as a capacity resource, and active power management of variable power generation. The report closes with a discussion of the GE team’s views on the best practices for integrating variable generation.