What is the difference between primary and secondary fuels?

The distinction between primary and secondary fuels primarily lies in their state of processing and form. Primary fuels are raw energy sources that are obtained directly from natural resources without undergoing any conversion or processing. Examples of primary fuels include coal, crude oil, natural gas, and biomass. These fuels are extracted or harvested directly from the environment in their natural form.

On the other hand, secondary fuels are derived from primary fuels through various processes and transformations. They are generally more processed forms of energy that are ready for immediate use in energy systems. Typical examples of secondary fuels include gasoline, diesel, and electricity, which come from the refinement or conversion of primary fuels.

Understanding this differentiation highlights the energy hierarchy that exists, where primary fuels serve as the foundational sources and secondary fuels play a substantial role in energy supply and utilization in various applications. This knowledge is essential for grasping energy systems and their components effectively.