Secondary energy is any energy obtained by transformation, as opposed to primary energy, which is energy available in the environment that does not require transformation.
This energy is often easier to store, transport and use than sources of primary energy.
This is why forms of secondary energy are called energy carriers. This is especially the case for electricity, refined oil fuels (petrol, diesel oil) or even, in the future, hydrogen.
Wind generators convert mechanical wind energy into a secondary energy: electricity. © farlane CC by-nc 2.0
Secondary energy - 1 Photo