Today the primary challenge confronting engineers is to develop clean, sustainable technologies that can meet the needs of all of the world's people. Traditionally this effort has focused on meeting the needs of the developed world. It is generally assumed that products needed for the developing world already exist or are relatively simple and hence do not require significant engineering design effort. As a consequence, many of the products intended to meet the needs of the poor miss the mark and do not meet their needs. This is particularly true in the design of products and processes intended to address the energy needs of the rural poor. Too often a set of standard assumptions is used, resulting in poor problem definition. And, because the design problem is not well defined, the resulting products and processes fail. Throughout the developing world it is common to find village water and energy projects that have failed. To design products and processes that meet the energy needs of the rural poor, the critical first step in the design process is a detailed in-village study of energy production and consumption dynamics. Quantifying village energy dynamics provides insight into the unfulfilled or unsatisfied needs of the consumer, establishes the design constraints, aids the engineer and the community members in prioritizing needs, and builds trust with the local community. This paper presents a field methodology developed to understand the energy needs of a rural sub-Saharan village of 700 people and discusses how this field methodology was used to establish the design constraints needed for a comprehensive energy solution.