To answer the following questions, the authors developed a model that analyzes the costs of expanding the power sector over the course of 10 years under different assumptions: Which type of power generation is right in which settings? Should individual countries move ahead independently, or should they aim for coordinated development? What are the benefits of regional trade in power, and who are the main beneficiaries? How should major global trends, such as rising oil prices and looming climate change, affect decisions about power generation in Africa? How rapidly can Africa electrify? How sensitive are power investment decisions to broader macroeconomic conditions? The model simulates optimal (least-cost) strategies for generating, transmitting, and distributing electricity in response to demand increases in 43 countries of Sub-Saharan Africa, grouped into four power pools.