Energy demand is expected to grow over the next century as more countries seek a better quality of life for their citizens. This demand will be met by a global energy mix; the current fossil-fuel-dominated portfolio is undergoing a transition to one that includes a range of fuel types. This paper presents an overview of energy sources available for use in the 21st Century and a prediction of the contribution of hydrocarbon oil and gas to the 21st Century energy mix. It also discusses the implications for petroleum engineering education and the emergence of a new type of energy industry.