What are secondary energy sources?

Secondary energy sources are called energy carriers, because they move energy in a useable form from one place to another. Two well-known energy carriers are

People make electricity and hydrogen from primary energy sources such as coal, natural gas, nuclear energy, petroleum, and renewable energy sources (biomass, geothermal, hydropower, solar energy, and wind energy).

For many energy needs, using electricity is easier than using a primary energy source. For example, using electricity for lighting is safer than using petroleum in candles or kerosene lamps. Electricity also enables people to use devices like televisions, computers, and cell phones, which cannot be directly powered with primary energy sources.