the sustainable use, production, and storage of energy, through efficiency, conservation and renewable resources. Use this tag for questions on energy in general.

Energy is the ability to do work and/or produce heat. While there are many forms of energy, the most commonly utilized in human society are electric, chemical, nuclear, radiant, and thermal energy.

Energy is needed to produce food, purify water, produce goods, transport goods and humans, and heat and cool human habitats.

There many ways to produce energy to accomplish these tasks, some of which are more or less sustainable than others: see , , , and .

In some cases, use of energy can be entirely avoided: see .

In other cases, less energy can be used to accomplish the same task: see .