Book Summary: “Energy and Civilization: A History” by Vaclav Smil

Title: Energy and Civilization: A History
Author: Vaclav Smil
Scope: 5 stars
Readability: 4 stars
My personal rating: 5 stars
See more on my book rating system.

If you enjoy this summary, please support the author by buying the book.

Topic of Book

Smil explains the role of energy is sustaining societies throughout human history.

My Comments

Vaclav Smil has written so many outstanding books related to the topic of energy. Picking one out as the best is very difficult, but this book is the best introduction to his thinking.

Key Take-aways

  • Energy is the foundation of human societies, even life itself.
  • All living being fight against the Second Law of Thermodynamics to life in the universe that tends toward chaos. In other word, life creates order from chaos.
  • A key metric is energy density, which measure the amount of energy per unit of mass.
  • Agricultural societies have relied on grain because of their high yield and energy density.
  • Fossil fuels have unusually high energy density, hence their extreme usefulness for humanity.

Important Quotes from Book

“Energy is the only universal currency: one of its many forms must be transformed to get anything done.”

“All natural processes and all human actions are, in the most fundamental physical sense, transformations of energy.”

“Life on Earth—despite decades of attempts to catch a meaningful extraterrestrial signal, still the only life in the universe we know of—would be impossible without the photosynthetic conversion of solar energy into phytomass (plant biomass). Humans depend on this transformation for their survival, and on many more energy flows for their civilized existence.”

“The evolution of human societies has resulted in larger populations, a growing complexity of social and productive arrangements, and a higher quality of life for a growing number of people. From a fundamental biophysical perspective, both prehistoric human evolution and the course of history can be seen as the quest for controlling greater stores and flows of more concentrated and more versatile forms of energy and converting them, in more affordable ways at lower costs and with higher efficiencies, into heat, light, and motion. ”

“Human dependence on ever higher energy flows can be seen as an inevitable continuation of organismic evolution.”

“fusion powers the Sun, and the product of those thermonuclear reactions reaches Earth as electromagnetic (solar, radiant) energy.”

“Only a tiny part of the incoming radiant energy, less than 0.05%, is transformed by photosynthesis into new stores of chemical energy in plants, providing the irreplaceable foundation for all higher life.”

“A fundamental distinguishing characteristic of our species has been the extension of these physical limits through a more efficient use of muscles and through the harnessing of energies outside our own bodies.”

“As with any nonphotosynthesizing organism, the most fundamental human energy need is for food.”

“The combustion of fossil fuels and the generation of electricity created a new form of high-energy civilization whose expansion has now encompassed the whole planet “Entropic dissipation leads to a loss of complexity and to greater disorder and homogeneity in any closed system. But all living organisms, whether the smallest bacteria or a global civilization, temporarily defy this trend by importing and metabolizing energy. This means that every living organism must be an open system, maintaining a continuous inflow and outflow of energy and matter. As long as they are alive, these systems cannot be in a state of chemical and thermodynamic equilibrium ”

“Another important rate is energy density, the amount of energy per unit mass of a resource (box 1.4). This value is of a critical importance for foodstuffs: even where abundant, low-energy-density foods could never become staples.”


“Only grains combine fairly high yields—initially only about 500 kg/ha; eventually, in the most intensive traditional agricultures, more than 2 t/ha—with high shares of easily digestible carbohydrates and a moderately high level of proteins (some, above all corn, also have a significant amount of lipids). Their energy density at maturity (15–16 MJ/kg) is roughly five times that of fresh tubers, and their moisture content when air-dried is low enough to allow long-term storage (in vessels by households, on a large scale in granaries). Staple grains also mature fast enough—traditional varieties mature in 100–150 days—to permit increased food productivity through annual rotations with other crops (mainly oilseeds and grain legumes) or by double-cropping of cereals.”

“all traditional agricultures shared the same energetic foundation. They were powered by the photosynthetic conversion of solar radiation, producing food for people, feed for animals, recycled wastes for the replenishment of soil fertility, and fuels for smelting the metals needed to make simple farm tools. ”

“Besides plowing, the dominance of cereal grains in annual cropping was certainly the other most obvious common trait of all Old World agricultures.”

“Dependence on cereal grains is thus a matter of clear energy advantages. Their primacy stems from the combination of fairly high yields, good nutritional value (high in filling carbohydrates, moderately rich in proteins), a relatively high energy density at maturity (roughly five times higher than for tubers), and a low moisture content suitable for long-term storage (in well-ventilated storage they do not spoil when grains contain less than 14.5% water). The dominance of a particular species is largely a matter of environmental circumstances (above all the length of the vegetation period, the presence of suitable soils, and the availability of adequate water) and taste preferences. In terms of total energy content, all cereals are remarkably similar: differences between mature seeds of various grains are mostly less than 10%”

“All animal foods and all mushrooms supply perfect proteins (with adequate proportions of all nine essential amino acids), but all four leading staple grains (wheat, rice, corn, millet) and other important cereals (barley, oats, rye) are deficient in lysine, while tubers and most legumes are short of methionine and cysteine.”

“A simple solution of this fundamental deficiency by including grains and legumes in mixed diets.”

“Before the introduction of reapers and binders, manual grain harvesting was the most time-consuming task, taking three to four times longer than plowing, and it put clear limits on the maximum area manageable by a single family. When a crop had to be harvested fast in order to plant the next one, the labor demand soared.”

“No quest for higher yields could succeed without three essential advances. The first one was a partial replacement of human work by animal labor. ”

“This prime mover shift did more than make the work quicker and easier; it also improved its quality, whether in plowing, seeding, or threshing. Second, irrigation and fertilization moderated, if not altogether removed, the two key constraints on crop productivity, shortages of water and nutrients. Third, growing a greater variety of crops, either by multicropping or in rotations, made traditional cultivation both more resilient and more productive.”

“Despite the slow progress in yields and labor productivities, traditional farming was an enormous evolutionary success. There would be no complex cultures without high population densities supported by permanent cropping.”

“But there were clear limits to population densities achievable with traditional farming. Moreover, average food supply was rarely much above the existential minimum, and seasonal hunger and recurrent famines weakened”

“Energy supply was the most common limit to the process of substituting animal draft for human labor. ”

“The limits to population density in societies undergoing agricultural involution were reached by the ability to subsist on gradually diminishing per capita returns of human labor. These gains became eventually limited by the maximum possibilities of nitrogen recycling.”

“no traditional agriculture could consistently produce enough food to eliminate extensive malnutrition. All of them were vulnerable to major famines, and even the societies practicing the most intensive cultivation were not immune to recurrent catastrophes, with droughts and floods being the most common natural triggers.”

Preindustrial Prime Movers and Fuel

“Animate labor and conversions of the kinetic energies of water and wind (by sails and mills) were the only prime movers in traditional societies before the diffusion of steam engines.”

“Animate energies remained the most important prime mover for most of humanity until the middle of the twentieth century. Their limited power, circumscribed by the metabolic requirements and mechanical properties of animal and human bodies, restricted the reach of preindustrial civilizations. ”

“Waterwheels were the most efficient traditional energy converters. Their efficiencies were superior even when compared to the best steam engines, ”

“Waterwheels were indispensable during the early stages of both European and North American industrialization. Waterwheels reached their apogee—whether evaluated in terms of individual or total capacities or in terms of efficiency of design—during the nineteenth century,”

“New turbine designs replaced waterwheels as the prime movers in many industries. For example, in Massachusetts they accounted for 80% of installed power by 1875. That was also the time of the greatest importance of water-driven machines in a rapidly industrializing society.”

“The era of water turbines as direct prime movers rotating geared and belted shafts ended rather abruptly. By 1880 large-scale coal mining and more efficient engines had made steam cheaper than water power virtually anywhere in the United States.”

“Windmills became the most powerful prime movers of the preindustrial era in flatlands where almost nonexistent water heads precluded the construction of small waterwheels (in the Netherlands, Denmark, and parts of England) and in a number of arid Asian and European regions with seasonally strong winds.”

“charcoal contains only a trace of moisture, and it was a biomass fuel always preferred by those who could afford its price.

This high-quality fuel is virtually smokeless, and its energy content, equal to that of good bituminous coal, is roughly 50% higher than that of air-dried wood. Charcoal’s other main advantage is its high purity. Because it is virtually pure carbon, it contains hardly any sulfur or phosphorus. This makes it the best possible fuel not only for indoor uses but also in kilns producing bricks, tiles, and lime and in the smelting of ores.”

“An ancient Chinese proverb had the right order of things that people cannot do without every day: firewood, rice, oil, salt, sauce, vinegar, and tea.”

“Walking and running, the two natural modes of human locomotion, have accounted for most of the personal movements in all preindustrial societies. ”

“The domestication of horses not only introduced a new and more powerful and faster means of personal transport, it was also associated with the diffusion of Indo-European languages, bronze metallurgy, and new ways of warfare”

“Human-powered waterborne movement achieved much higher power ratings than animate transport on land. ”

Fossil Fuels

“The transition to fossil fuels has also entailed two classes of fundamental qualitative improvements, and only their accumulation and combination have produced the energetic foundations of the modern world. The first category of these advances was the invention, development, and eventually mass-scale diffusion of new ways to convert fossil fuels: by introducing new prime movers—starting with steam engines and progressing to internal combustion engines, steam turbines, and gas turbines—and by coming up with new processes to transform raw fuels, including the production of metallurgical coke from coal, the refining of crude oils to produce a wide range of liquids and nonfuel materials, and the use of coals and hydrocarbons as feedstock in new chemical syntheses.

The second class of inventions used fossil fuels to produce electricity, an entirely new kind of commercial energy. ”

“Coal was generally the dominant fossil fuel in the European transition.”

“The replacement of charcoal by metallurgical coke in pig (or cast) iron smelting belongs undoubtedly to the greatest technical innovations of the modern era as it accomplished two fundamental changes, severing the industry’s dependence on wood (and hence requiring furnace locations in or near forested regions) and allowing much larger furnace capacities and hence a rapid increase in annual production. Moreover, it was also a replacement by a superior metallurgical fuel.”

“Steam engine was the first new prime mover successfully introduced since the adoption of windmills, which preceded it by more than 800 years. ”

“But its full impact came only after 1840, with the rapid construction of railroads and steamships and with more installations as a centralized producer of kinetic energy (transmitted by belts to individual machines) in manufacturing enterprises.”

“The generation of electricity, its transmission, and its conversion to heat, light, motion, and chemical potential represented an unparalleled achievement among energy innovations. Previously, new energy sources and new prime movers had been designed to do specific tasks faster, cheaper, or with more power, and they could easily be used within existing productive arrangements (for example, millstones were turned by a waterwheel instead of by animals). In contrast, the introduction of electricity required the invention, development, and installation of a whole new system required to generate it reliably and affordably, to transmit it safely over long-distance transmission and distribute it locally to individual consumers, and to convert it efficiently in order to deliver the final forms of energy desired by users.”

“The post-1900 extraction of fossil fuels has been marked by three notable trends. First, the global expansion of coal mining and hydrocarbon production raised the annual extraction of fossil carbon roughly 20-fold between 1900 and 2015”

“Second, numerous technical advances have been the most important enablers of this expansion, resulting in cheaper and more productive extraction, transportation, and processing methods as well as in reduced specific pollution rates (and, in one remarkable case, even in an absolute global emission decline). Third, there has been a clear secular shift toward higher-quality fuels, that is, from coals to crude oil and natural gas, a process that has resulted in relative decarbonization”

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