The Power Systems Planning Group, embedded in the Energy Sector Management Assistance Program (ESMAP), has created the Electricity Planning Model (EPM) as a least-cost planning framework. EPM minimizes the costs of expanding and operating a power system while meeting the model's technical, economic, and environmental requirements. EPM is a long-term planning model, which means it optimizes the annual capacity additions based on system costs over multiple years, including fixed (annualized capital and fixed operation and maintenance [O&M]) costs and variable (fuel and variable O&M) costs. Moreover, EPM addresses the dispatch of the generators, decides on the activities per geographical zone and the exchange between them. Furthermore, the model suggests the allocation of spinning reserves among generators and allows for implementing different policies, e.g., emissions limits, fuel, and import limits, spinning reserve requirements, transmissions caps, ramp limits, or carbon prices. As part of the implementation of EPM studies with World Bank clients, more than 100 comprehensive country or regional datasets have been developed to support the model development. As the EPM datasets are openly licensed they, in addition, offer an affordable alternative to costly commercial databases.