For most of human history, muscle power was the most important source of energy – for example, in the construction of buildings or the production of goods. Although environmentally friendly, this method is very exhausting. Over the course of time, people looked for ways to make hard work easier by employing levers, tackles and draught animals. In this pre-industrial age, energy was generated where it was needed. Sunlight and log fires were the sources of light and warmth; water and wind delivered kinetic energy.
Energy
Permanent
