Tag Archives: history

Human Energy, Embodied Energy

Humans, as just about all living thing, have a capacity to do work. By subtracting the energy we need for basal metabolism from total caloric intake we get a measure of useful work. For an average American, we do about 500-1000 kilocalories of work daily. Converted to kilowatt-hours (kWh) it’s only 1.2 kWh.

We consume vast amounts of additional energy in the form of electricity and gasoline to name just two, and the indirect energy embodied in the goods and services we use in modern society. If we add it all up and convert it to a single unit, it comes to 220 kWh per day. It is as if we all employ over 200 slaves a day! How in the world did we get here?

One place to begin is with human control of fire. There is clear evidence of the control of fire 200 to 300 thousand years ago, which roughly corresponds with modern humans, Homo sapiens. However there is growing evidence of the use of fire goes as far back as a million years ago. Not only did fire provide warmth and protection but also increased nutrition.

Only a slight step up from burning wood was the use of charcoal. This was important for the advancement of the various metal ages. Copper and Tin were ores easily smelted using charcoal which provided both an energy source and a chemical reactant for making metals. The bronze age, bronze being made principally from Copper and Tin, dates to the dawn of civilization – about 6000 BCE, 8000 years ago. This begins the use of embodied energy, rather than direct energy use.

The next step was a giant one, the identification of fossil fuels as energy sources. The demarcation of modern life begins with the industrial revolution around 18th to 19th centuries. This is the age of coal and iron and mechanization. The steam engine powered by coal not only revolutionized manufacturing but also transportation via steam trains and ships.

The beginning of the age of oil is usually connected to Edwin Drake’s oil well near Titusville, PA. Crude oil and its refined products rapidly displaced other energy sources because of convenience. Our success in World War II was due in large part to our exploitation of fossil fuels for manufacturing and transportation.

World War II also ushered in the atomic age, first with bombs, then “atoms for peace.” The first civilian nuclear reactor in the US (the first in the world was in the Soviet Union) was in Shippingport, PA in 1958.

As our consumption of crude oil continued to increase, by 1969 our ability to produce oil peaked. Shortly thereafter the Organization of Petroleum States formed, began an embargo, and caused the US to realize that in terms of energy we are not be the masters of our fate.

Loss of control of the oil market, coupled with the increasing recognition of the harmful effects of the burning of fossil fuels ushered in the beginning of renewable, or better described sustainable energy sources, notably wind and solar.