Primary energy vs. secondary energy

Primary energy is energy in the form it's first accounted for, before any conversion: coal, crude oil, natural gas, or sunlight, for example. Secondary energy is what primary energy gets converted into for practical use, most importantly electricity. Electricity itself isn't a primary energy source; it's a secondary energy carrier produced by converting something else (coal, natural gas, uranium, wind, sunlight) into electrical form. This is a commonly misunderstood point worth stating plainly for a newcomer.