Increasing growth of economic activity conditions increases energy consumption. This chapter introduces world energy consumption scenarios. Primary energy consumption tendencies, global energy consumption structure are presented, threats to sustainable energy future are revealed, and the role of renewables explained. In order to get a better understanding of energy, readers are acquainted with energy resources and energy sources. Such resources as electricity energy and heat production are introduced, primarily energy resources, and both nonrenewable (finite) and renewable are discussed. Special attention is paid to renewable resources, such as hydropower, solar and wind energy, sea tides and low tides, and wood and other plants. The chapter provides basic knowledge required to understand the importance of energy transformation toward sustainability.