The Potential of Energy Reservoirs and Deposits Activity Source: American Association of Petroleum Geologists Grade Levels: 6-12 Background All countries rely on multiple energy sources to power industries, homes, and transportation. The combination of energy sources used by a nation is called their energy mix. Energy comes in many forms, and some of the most important sources are stored beneath the Earth’s surface (known as reservoirs). Each of these sources plays a critical role in generating electricity around the world. [Read More]