An Energy History

Energy has been an organizing principle in human evolution and our societies. This chapter lays out the choices before us and shows the consequences of our energy decisions in the past.

At least two pivotal moments in human history can be viewed as advances in our use of energy. Agriculture was the organized conversion of solar energy to chemical food energy in a way that reduced the calories humans had to expend to harvest that food. With reduced energy going into food production, societies could advance in new ways. The industrial revolution was based on the conversion of coal, ancient fossilized plants, to mechanical energy. The energy output of a human being could be replaced by pile of black rocks. Machines could produce goods that required human energy and an explosion of both human wealth and threats to health began.

Learning Objectives

Understand energy as an organizing principle in human history

Energy in Antiquity

For much of human history, we used renewable sources of energy

Biological Energy Conversion

Plants convert radiant energy into chemical energy
Humans convert chemical energy into human activity

Food Gathering Techniques

Foraging
Hunting
Agriculture
Livestock
Which of these is our current energy system most like?

Fire

Stored chemical energy in wood to heat
Allowed for tool making
Allowed for cooking

Fire Sources

Wood, biomass, dung
Coal
Coke
Oil
Gas

Amplifying human power and energy

Ancient machines
- Lever
- Spring

Hunting Machines

Bow and arrow
- energy is stored in bow and released quickly
Spear and Lever
- Lever allows hunter to impart more kinetic energy to the spear than with the arm alone
Guns
- Chemical energy converted to kinetic energy in bullet

Human Thermoregulation

Our superior ability to remove heat energy from our bodies allows us to outrun prey animals

Livestock

Oxen
Horses
Allowed humans to cultivate more land, but required more land for food

Water power

Water wheels
- converts kinetic and potential energy in water to rotational motion
- estimated 500,000 waterwheels in Europe

Water Wheel

Wind power

Windmills
- converts kinetic energy in the wind to rotational motion
- Dates to Ancient Greece
- 12th century in Europe
- estimated 200,000 windmills at peak in Europe
- estimated 600,000 windmill waterpumps at peak in 1930 in United States
Sailing
- Allowed long distance travel

Ancient Windmill

American Pumping Windmill

Modern Electric Windmill

Industrial Revolution

Energy in the Fossil Fuel Era

The modern era is marked by the enormous productivity gains provided by fossil fuel energy
We can purchase the equivalent of one person’s labor for a day for about 10 cents

Steam Engine

Invented by James Watt in approximately 1770
Converts of chemical energy to heat to motion
Created shift in manufacturing technology

Internal Combustion Engine

Inventions in the 1800s lead to first automobile patent by Karl Benz in 1886

Electrification

Pearl Street Station
Steam-powered, coal-fired electricity generator
Fossil fuel is still widely used for electricity generation

Discussion

Choose on of these technologies and discuss
- Positive effects
- Negative effects

Consequences of Fossil Fuel Use

Global Warming

Widespread use of these fuels causes an increase in fossil carbon in the atmosphere
Arhennius in 1896 calculated how changes in the levels of CO₂ could alter surface temperature

Nuclear Energy

Mass converted to thermal energy
1950s see the first nuclear power plants

Solar Energy

“I’d put my money on solar energy…I hope we don’t have to wait till oil and coal run out before we tackle that.” Thomas Edison

Solar Energy

Photoelectric effect discovered in 1916 by Millikan
1950s solar photovoltaic cells used on satellites
Today, widespread use in private and commercial generation

Solar Adoption

40 years to get to 50 GW of PV capacity
50 GW again in the last 2.5 years

Future Energy Technologies?

What technical and financial innovations will allow for more low carbon energy solutions?