Campuses are increasingly looking to renewable energy as the most financially attractive strategy for achieving dramatic reductions in greenhouse gas emissions while reducing long-term energy costs and minimizing energy price risk. To achieve economies of scale when sourcing renewable energy, cohorts of colleges and universities are beginning to work together to aggregate their energy demand. This publication highlights the benefits of this approach. It also describes best practices for pursuing group renewable energy aggregations structured as power purchase agreements (PPAs) and examines several completed group purchases as well as some in progress.