Over three billion people live in the rural areas of low- and middle-income countries. Often rural households have many unmet energy needs, including cooking, lighting, heating, transportation, and telecommunication. But how are these needs identified? How is the problem defined? And by what methods and metrics should energy options be compared? Answering these questions requires an understanding of the human, natural, and engineered systems that drive village energy dynamics.The first half of this webinar presents the results of a novel study of energy supply and use over a one-year period in an isolated rural village of 770 people in Mali. Quantitative data and narrative descriptions from this study portray village energy supply and use. Wood and electricity provide six vital functions that meet basic human needs, yet do so in very different ways. The second half of the webinar uses the Hybrid Optimization Model for Electric Renewables (HOMER) to investigate options to meet the power needs of off-grid rural villages similar to the village described in Mali. Originally developed through the Village Power Program at the U.S. National Renewable Energy Laboratory, HOMER has over 70,000 users throughout the world.