Energy

Remarkably, modern science is not very clear on what exactly energy is. The term defies clear definition, so much so that famous physicist Richard Feynman said "it is important to realize that in physics today, we have no knowledge of what energy is. We do not have a picture that energy comes in little blobs of a definite amount". The world's most popular thermodynamics textbook, by Yunus Cengel and Michael Boles has this to say on the subject: "Thermodynamics can be defined as the science of energy. Although everybody has a feeling of what energy is, it is difficult to give a precise definition for it. Energy can be viewed as the ability to cause changes".

A common definition usually heard is that energy is the ability to do work. Wikipedia has a more precise definition: "In physics, energy is the quantitative property that must be transferred to an object in order to perform work on, or to heat, the object".

Fig.1. Quality-of-life-related variables and energy consumption rate per capita ECR: Improved water access WA, life expectanc

Fig.1. Quality-of-life-related variables and energy consumption rate per capita ECR: Improved water access WA, life expectancy LE, infant mortality IM, mean years of schooling MYS, electrification level EL, and gross national income GNI, Correlation coefficient in parentheses (infant mortality and gross national income are considered in logarithmic scale). Note: Data for 118 countries with populations larger than four million in 2005.

I like to think of energy as an animating force that can move or heat objects, and access to energy is the ability to command this force to perform tasks valuable to humans. The importance of this ability cannot be overstated. The progress in the quality of human life can best be understood as the increase in the energy available to the human being to perform the tasks they want. Comparisons across the world today, and across time, can vividly illustrate the enormous value that access to energy entails. Our modern world is largely the product of the development of technologies that give us regular access to huge quantities of energy. Modern civilization and most of its achievements and essentials would not be possible without levels of energy consumption that are complete outliers by historical standards.

The attached Figure 2, from the study 'Energy Consumption and Quality of Life' by Cesar Pasten and Juan Carlos Santamarina shows the correlation of energy consumption per capita with improved water access, life expectancy, infant mortality, mean years of schooling, electrification, and gross national income. As is apparent, the more a society is able to harness and consume energy, the more it is able to provide itself the basic needs of modern life.

energy use per capita vs. GDP per capita, 2015

Figure 3

Taking a closer look at GDP, the relationship is very clear and has been for a very long time: More energy consumption translates to more economic production, and consequently, better standards of living.

Figure 4 shows the relationship between energy consumption per capita and the share of the population living in extreme poverty. No country that eliminated extreme poverty consumes less than 10,000kWh/capita/year, and no country that has more than 20% of its population in extreme poverty consumes more than 10,000kWh/ capita/year.

energy use per capita vs. share of population in extreme poverty, 2003

Figure 4

The progress of humanity has been driven by technological advancements that unlock the the energy latent in hydrocarbon fuels. The fact that most humans today live protected from most of nature's harms, can stay warm in the winter, and can travel faster than their running speed is due to the industrial revolution innovations that gave us various forms of engines to access the energy present in the three main hydrocarbon fuels: coal, oil, and gas. As John Cross put it:

"The history of economic development is the history of the amount of energy brought under human control. Economic historians have observed the close relationship between economic growth and energy consumption as we put more energy to work for us. American economist Deirdre McCloskey called the surge in energy use that began around 1800 "the Great Enrichment". The benefits to mankind have been enormous, extending life expectancy, increasing food output to sustain burgeoning populations, and lifting the standard of living for most people to levels not even royalty could aspire to just a few centuries ago.

The late Italian economic historian Carlo Cipolla attributed both the Agricultural Revolution thousands of years ago and the Industrial Revolution starting in the late 18th century to people harnessing energy power…

Fossil fuels played a negligible role in supplying energy until the Industrial Revolution. While everything on the planet is a possible source of energy, fossil fuels proved especially efficient and convenient in meeting the energy demands of industrialization. In Cipol la's words, the Industrial Revolution "can be regarded as the process whereby the large-scale exploitation of new sources of energy by means of inanimate converters was set on foot". Coal was the first widespread source of inanimate energy, rising from 10 percent of Britain's energy supply in 1560 to 60 percent by 1750, in the process ending Britain's deforestation. This began a cumulative process, where a rising supply of energy stimulated more economic growth, which boosted education that led to the discovery of new sources of energy, notably other fossil fuels.

The first commercial use of fossil fuels was kerosene to generate light and end our perpetual plunge into darkness after sundown. (This stopped the widespread slaughter of whales, whose oil until then was the main source of indoor light.) The U.S. pioneered the exploitation of oil in the 19th century, a mantle it is reclaiming today thanks to innovative technologies to develop shale deposits. By 1860, the oil age had begun in earnest due to the development of drilling technology in Pennsylvania.

In his excellent book The Moral Case for Fossil Fuels, Alex Epstein makes the compelling case for how hydrocarbon fuels are the root of modern prosperity. Life everywhere until the 16th century primarily relied on burning wood for the provision of energy. Compared to modern hydrocarbons, wood contains much less energy per unit of weight. As the utilization of coal started in the 16th century, and later was followed by oil and gas, the amount of energy available per person expanded enormously, and with it our quality of life. To visualize the true benefit of energy for our lives, Epstein invites you to imagine the energy you consume today in terms of the energy consumption of humans performing tasks for you. By that measure, he finds that the average American has 186,000 calories at his service daily, or the energy equivalent of 93 humans. Before modern fuels, such an amount of energy was rarely ever available for anyone. Only the richest kings could dream of having as much energy at their daily disposal, either in the form of combustible wood, or enslaved humans.

Another way to appreciate the importance of hydrocarbon fuels to our modern way of life is to realize how much more power it has afforded us. In physics, power is defined as the rate of doing work over time, which is what matters for many jobs that call for high quantities of energy over short periods of time, such as moving heavy weights. For instance, energy is plentiful in sunlight and wind, but it's difficult to quickly harness it for generating enough power to move heavy loads. The introduction of hydrocarbon fuels has vastly increased humanity's potential for generating power, as can be seen from Figure 5 taken from Vaclav Smil's World History and Energy:

global primary energy consumption

Figure 5

The amount of power that a modern day steam turbine produces is more than a million times the power that can be produced by a horse, which was the state of the art in power generation up until around 2,500 years ago. It is worth noting that the power from water turbines is almost up there with the power of steam turbines. Water turbines are placed at rivers and waterfalls and, combined with an electric generator, they convert running water's energy into electricity. Hydroelectric energy is responsible for around 16% of global electricity production.

As human ingenuity has advanced, the ways in which we've taken advantage of the naturally occurring energy in our planet have multiplied in both magnitude and efficiency. The result is that people every day from all around the world are climbing out of poverty is in no small part due to their ability to use more energy in their daily life.

Figure 2: The maximum power of prime movers shown as the sequence of the higher capacity converters for the span of the past

Figure 2:  The maximum power of prime movers shown as the sequence of the higher capacity converters for the span of the past 3000 years (A) and shown in the detail for the periods 1000 BCE and 1700 CE to 2000 CE (B and C).