"Sources of energy" is divided into which of the following categories?

Commercial and non-commercial sources of energy

Sources of energy can be categorized into commercial and non-commercial sources of energy. Commercial sources are coal, petroleum and electricity as they are bought and sold. Non-commercial sources of energy are fuelwood, agricultural waste and dried dung. These are non-commercial as they are not available in the market on a large scale. While commercial sources of energy are generally exhaustible (with the exception of hydropower), non-commercial sources or traditional are generally renewable.