Most popular way to make electricity today is to heat up lots of water (via burning coal or uranium) to temperatures on the order of 500 degrees C (1000 F), and

Most popular way to make electricity today is to heat up lots of water (via burning coal or uranium) to temperatures on the order of 500 degrees C (1000 F), and have the resulting steam power the turbine, which generates electricity by spinning magnets. This process is generally 20-40% efficient, that is, only 20-40% of generated energy is turned into electricity. The rest of the energy is waste heat of steam that cooled down so much that it's no longer economical to generate electricity from it (because the efficiency of the process goes down as the temperature difference between working fluid and environment goes down). The result is that more than half of the energy simply disappears in the thin air. To increase efficiency, many cities run cogeneration plant, where the waste heat from electricity generation is piped into municipal heating system. In this scenario, the incandescent bulbs are wasteful way to heat the house, because it only uses 20-40% of the energy of the fuel, while municipal heating uses only waste energy to produce eletricity.