The energy industry can be organized into three distinct divisions: energy sources, forms of energy (electricity and heat), and end uses of energy (transportation, lighting, space conditioning, industrial processes and agricultural needs). These categories can be separated into its leading sectors. These sectors include fossil fuels, water, wind, solar, geothermal, and nuclear sources. There are many jobs common to all sectors but the number one job in the energy industry is engineer. Each sector needs engineers and often many different kinds of engineers.