# Muscles, wood, water and wind: energy before fossil fuels For almost all of history, energy came from food eaten by people and animals, from wood and charcoal burned for heat, and from water and wind turning wheels and filling sails. These sources delivered power in units of tens of watts to a few kilowatts and drew on the same limited land, which capped yields, population and output. About two billion people still cook with polluting fuels, mostly wood, charcoal, crop residues and dung, so this old energy system remains part of the present. Source page: https://www.materialinsights.org/learn/energy/energy-before-fossil-fuels/ [Understanding Energy](https://www.materialinsights.org/learn/energy/) / Module 4 ## Muscles, wood, water and wind: energy before fossil fuels For almost all of history, energy came from food eaten by people and animals, from wood and charcoal burned for heat, and from water and wind turning wheels and filling sails. These sources delivered power in units of tens of watts to a few kilowatts and drew on the same limited land, which capped yields, population and output. About two billion people still cook with polluting fuels, mostly wood, charcoal, crop residues and dung, so this old energy system remains part of the present. 4 parts · 15 sections · about 45 minutes · 0 of 4 parts read ### By the end you will be able to - Calculate a person's daily energy need from basal metabolism and activity level, and explain why sustained human work is only 50-100 W - Explain why farming spread despite giving less food per hour of work, and what limited traditional yields - Compare the power of humans, draught animals, waterwheels, windmills and sails, and the limits of each - Describe how wood and charcoal supplied heat and metals, and why their low power density capped the organic economy - Assess the scale, trends and costs of traditional biomass cooking today using current IEA and WHO figures ### Contents 1. [Part 1 The human body as an energy converter](https://www.materialinsights.org/learn/energy/energy-before-fossil-fuels/p1/) For almost all of history the main machine in any economy was the human body. It takes in food, keeps itself alive, and turns a modest share of that food into work. Knowing how much energy a person needs, how much useful power a person can deliver and what limits that power explains why every society that could afford it looked for animals, water, wind and finally fossil fuels to do the work instead. - Most of the food we eat simply keeps us alive - A person can sustain only 50 to 100 W of useful work, at about a quarter efficiency - Endurance, not speed, is the human strength, and organisation multiplied it 2. [Part 2 Foraging and farming: food as the first energy system](https://www.materialinsights.org/learn/energy/energy-before-fossil-fuels/p2/) Before there were fuels and engines, the main energy system was the food system. For more than 95% of human history people lived by gathering, hunting and fishing. Farming, which began about 10,000 years ago, did not make life easier at first, but it fed far more people per hectare. Its long improvement and its hard ceiling set the conditions that fossil fuels later broke. - Foragers lived on net energy returns, at densities below one person per square kilometre - Agriculture won by feeding more people per hectare, not by saving work - Traditional farming intensified with animals, water, manure and rotations - The organic ceiling: low yields, scarce nitrogen and recurrent famine 3. [Part 3 Animals, water and wind: the first prime movers beyond the body](https://www.materialinsights.org/learn/energy/energy-before-fossil-fuels/p3/) A prime mover is anything that turns a primary energy flow into mechanical work. Smil reads history as a sequence of ever more powerful prime movers. Before steam, the sequence ran from human muscles to draught animals, then to waterwheels, windmills and sails. Each step multiplied the power available at one place, but none escaped the limits of organic and natural flows. - Draught animals gave several times human power, if harnessed well and fed - Waterwheels were the first inanimate prime movers and ran Europe's early industry - Windmills turned an unreliable flow into work where water was scarce or flat - Sails and waterways carried the bulk of preindustrial trade 4. [Part 4 Wood, charcoal and the limits of the organic economy](https://www.materialinsights.org/learn/energy/energy-before-fossil-fuels/p4/) Mechanical work came from muscles, water and wind, but heat came almost entirely from burning plants. Wood, charcoal, straw and dung cooked food, warmed homes, fired kilns and smelted metals. The heavy demands of metallurgy and cities stripped forests and set a ceiling on what a society running on current photosynthesis could do. That world has not fully passed: about two billion people still cook on polluting fuels, mostly solid biomass. - Wood was the universal fuel, and straw and dung filled the gaps - Charcoal made high temperatures possible, at a heavy cost in forests - Building, fighting and the ceiling of an economy on current sunlight - About two billion people still cook with polluting fuels, mostly biomass 5. [Wrap-up Key terms, try it in the table, final quiz, sources](https://www.materialinsights.org/learn/energy/energy-before-fossil-fuels/review/) [Start: Part 1, The human body as an energy converter →](https://www.materialinsights.org/learn/energy/energy-before-fossil-fuels/p1/) ## Other sections - [The human body as an energy converter](https://www.materialinsights.org/learn/energy/energy-before-fossil-fuels/p1/index.md) - [Foraging and farming: food as the first energy system](https://www.materialinsights.org/learn/energy/energy-before-fossil-fuels/p2/index.md) - [Animals, water and wind: the first prime movers beyond the body](https://www.materialinsights.org/learn/energy/energy-before-fossil-fuels/p3/index.md) - [Wood, charcoal and the limits of the organic economy](https://www.materialinsights.org/learn/energy/energy-before-fossil-fuels/p4/index.md) - [Key terms, quiz and sources](https://www.materialinsights.org/learn/energy/energy-before-fossil-fuels/review/index.md)