Energy is the Universal Solvent
Precis of Energies by Vaclav Smil
Don’t read this book for the thesis; read it for the evidence. Is every physical process fundamentally an energy conversion process? Is power output in penguin propulsion, the sun’s core, steam turbines, and human alcohol metabolism really comparable?
I don’t know. But this book does casually mention that
• penguins expend half as much energy and increase their sustained speed by 20% when they swim entirely submerged rather than at or near the surface
• the sun’s core consumes 4.3 million tonnes of matter every second and solar radiation does not attenuate almost at all in space
• steam turbines improved in capacity until demand for new generation dropped so they started to get better at efficiency and reliability
• an average active farmer can get 20% of their calories from a bottle of wine a day, and this will only use his liver to 40% of its maximum whereas an inactive alcoholic can drink a bottle of whiskey and only get 2/3 of basic caloric requirements for the day
The thesis, that everything can be compared in terms of energy, is technically present in all such claims, but I’m not convinced that it’s important. That there does exist a terminology to link together these concepts does not really mean that it’s important.
However, the fun facts, about penguins and farmers and turbines and stars, range from grounding to absolutely shocking. And they make this book kick ass. In fact, I went ahead and quoted a bunch of them and here they follow!
The Best Fun Facts
Earth and Sun
Solar luiminosity has increased by 40% in the last 4.5 billion years, but the Earth’s climate has remained fairly constant during this time. (p 4)
Earthquakes account for about .03% of the total flow of Earth’s heat. (p 27)
Volcanoes account for 2%. (p 31)
A nearby supernova should occur about every 2 billion years within 10 parsecs of the Earth; when one happens near us it should kill all vertebrates on the surface with deadly high-frequency radiation. There is no evidence that this has happened yet. (p 35)
Flora
Forests and grasslands have much more phytomass than oceanic phytoplankton. (p 37)
Global photosynthetic efficiency (proportion of energy from the sun that is collected) is about .6%. In the oceans it is .06% and in marshes and forests it reaches 1.5%. Some plants can, individually, reach 5% efficiency. (p 44)
“Grass is now North America’s largest crop in terms of area, covering roughly an equivalent of Pennsylvania.” Mowing to 5 cm reduces productivity of the grass only by between 5 and 20%. (p 54)
Fauna
Endotherms (“warm-blooded” animals) own all the performance records in running, jumping, and flying. (p 37)
Humans produce and use more ATP daily than their own body weight. Other organisms use even more, with one soil bacteria producing 7,000 times more ATP than its own mass daily. (p 39)
“Feathers and furs are outstanding insulators: even at -30º C Arctic mammals have skin temperatures comparable to those of a well-clothed man.” (p 63)
“Numbers of herbivores are most often limited by the presence of carnivores rather than by the availability of phytomass; this means that grazers and leaf- and seed-eaters are rarely in direct competition. In contrast, numbers of plants (primary producers), decomposers, and carnivores are limited by the availability of their respective resources, a situation leading inevitably to considerable interspecific competition.” (p 64)
“Densities of heterotrophs decrease exponentially with their body weight” the complete plot ranging from the smallest bacteria to the largest mammals has a slope of -0.75, which means that the exponent for density decrease with body length will be -2.25. On the average, each square kilometer of land will support only few hundred vertebrates (reptiles, birds, mammals) with body lengths of 20–50 cm — but about 10 million inverterbrates measuring 0.2 — 0.5 cm. And because the rate of basal heterotrophic metabolism increases with the ¾ power of the body mass, energy harvested daily per unit area should be a constant independent of the size of individual herbivores. This mean that, as a general rule, no herbivorous species has a competitive advantage just because of its bigger size. Bigger bodies mean that although there are fewer individuals of the same species (and also fewer species and fewer species per genus) they intercept a share of biomass energy roughly identical to that eaten by vastly more numerous tiny heterotrophs.” (p 65–66)
“Success rates of canid and felid hunting can be very low; only a few percent of solo rushes can end in capture of the larger ungulates. Odds are greatly improved by ambushing prey (especially near water), and by group pursuit practiced by most canids. The latter technique also allows them to bring down animals of much larger size than themselves: wild dogs can kill wildebeest, wolves can subdue a moose.” (p 70)
“In general, because the power available for running goes up faster than the cost of the activity — the maximum oxygen intake rises with body mass to the power of 0.85 while the cost of running goes up with the power of 0.67 — large mammals can run up to ten times faster than the smallest animals.” (p 73)
“Jumping is a particularly interesting case of terrestrial locomotion with a counterintuitive performance limit: regardless of their body size, all animals should jump to roughly the same height. This is a consequence of energy output being directly proportional to the muscle mass, which will be generally proportional to the total body mass: the identical energy release per unit mass should then raise the animals to equal heights. Actual measurements confirm the similarity of jumping performances for animals whose body size differs more than 10⁸ fold. A flea (0.49 mg) jumps twenty centimeters, a locust (3 g) sixty centimeters, a man (70 kg) also sixty centimeters (this refers to the lifting of the body center during the best standing jump, which does not utilize the kinetic energy of athletic high jumping). The threefold difference between a flea and a man would virtually disappear if the tiny animal could jump in vacuum: for small insects the air resistance is very important, for large animals it hardly matters. The exceptions are achieved by disproportionate muscle mass.” (p 75)
“But the largest birds find it very difficult to produce enough power for sustained flight. As their weight increases, the power needed for flying rises faster (exponent 1.0) than the power which can be delivered by pectoral muscles (exponent 0.72). Consequently, there are few flying birds heavier than ten kilograms and none above sixteen kilograms, the weight of the heaviest Kori bustards in East Africa, which fly only rarely. Not surprisingly, all heavy fliers conserve their energy by spending much of their time gliding rather than flapping. Some gliders do not even use active flight to gain the initial height: they rely on circular soaring in thermal currents, and they can repeat the feat by gliding from thermal to thermal.” (p 77)
Human Energy
“Clearly, BMRs are highly individual, but the key qeuestion asked by Elsie Widdowson, an eminent British physiologist, in the late 1940s — “Why can one person live on half the calories of another, and yet remain a perfectly efficient physical machine?” — is yet to be answered satisfactorily. Inevitably, the answers will lie in finding the cause for substantial disparities in the functioning of internal organs which account for most of every individual’s basal metabolism. In relative terms, kidneys are metabolically the most active organs, followed by the heart, brain, and the liver. In absolute terms, the liver uses the largest share of BMR in adults (at least one-fifth), the brain in children.” (p 81)
“A horse can perspire at a rate of 100 g/m² an hour, a camel can lose up to 250 g/m² per hour — but a man can average more than 500 g/m² per hour. Without sweating average person would lose, about equally through respiration and skin diffusion, 12 W/m² of body surface, or just over 20 W in total. In contrast, hourly perspiration rate of 500 g/m² equates to heat loss of between 550–625 W for adults! Best acclimatized individuals can perspire up to 1,100 g/m² per hour, an equivalent of 1,390 W.
[…] Temporary partial dehydration is common during heavy work or long foot races, and it causes no problems as long as the water deficit is made up within the next day. […]
Our ability to cope with heat by sweating must be seen — together with bipedlaism, hairlessness, large brain, and symbolic linguistic ability — as one of the key defining human traits.”
(p 83)
During preganancy, “basal metabolism of active, healthy young women goes up by no more than 15–20 percent, an increase equivalent to food energy in just four slices of toasted whole-wheat bread a day!
[…] But these changes are not the norm. Impeccable studies in a number of Asian, African, and Latin American countries have shown that many women in poor rural areas have extremely low energy costs of both pregnancy and lactation. Compared to Western expectations, their energy shortfalls are up to about 3 MJ/day even if they would just sleep and rest, and up to 4 MJ considering their heavy labor. These women, giving birth to healthy children, maintain genuine energy balance on what seem to be incredibly low levels of food intake, commonly 20–40 and even close to 50 percent below the expected requirement!
[…] And among the Kauls of New Guinea, British researchers found no difference in average food-energy intakes of nonpregnant and nonlactating and pregnant lactating women!” (p 85)
“After adolescence, the body’s fat content increases steadily in both sexes, but the difference widens with age. Lipids make up about 15 percent of body weight in young Western adult males, but about 27 percent in females; by the seventh decade of life this disparity widens to 23 versus 36 percent. On the average, females are adding fat at rates of 0.3–0.4 kg/year, men at only 0.15/0.25kg/yera. This trend is accompanied by the loss of lean body mass.
Muscles are just over 50 percent of weight in young men, 40 percent in women. After the third decade the male’s greater lean mass is lost more rapidly (2–3 kg per decade) than teh female’s musculature (about 1.5 kg per decade), and people over seventy years average about 40 percent less muscle than they had as younug adults. This loss is an inexorable sign of physical aging even in those men and women who are in excellent health and who had avoided a significant fat increase.” (p 86)
“Thinking is an enormous energy bargain. The adult brain claims about a fifth of BMR, but even the hardest brainstorming makes little difference to that fixed rate: it requires no more than about four watts, equal to around 5 percent of a typical BMR.” (p 90)
“Consequently, even a hard-working lumberjack accomplished daily useful work equivalent to just 6 MJ. That much useful energy can be delivered, even when the overall conversion efficiency of an inanimate prime mover would be just 20 percent, by burning about seven hundred grams of crude oil or one kilogram of good coal. Clearly, human effort, even as its best, is a rather unimpressive source of mechanical energy.” (p 92)
Agriculture
“Carbohydrates not only ranked first, but they also accounted for the bulk of digested food in every traditional society; they still provide more than three-quarters of all food energy throughout the poor world, but in the richest countries their share has fallen below 50 percent.” (p 93)
“Hunting societies preferred killing the largest mammals not just because those animals provided plenty of meat, but also because that meat, in contrast to that of smaller creatures, was also uncommonly rich in fat. Bison provided twice as much energy per unit weight as an elk or a deer, and the same difference applied to elephants compared to even the largest antelopes. Similarly, the high fat content of Pacific baleen whales and salmon provided the energetic foundation for settled and relatively complex societies of the Pacific Northwest: precontact settlements totaled up to several thousand people, concentrations unattainable by hunting lean meat.” (p 99)
“Only an uninformed view would not perceive tens of thousands of years of hominid foraging as a prolonged prelude to a truly sapient existence in increasingly complex civilizations. To continue the musical analogy, it was very much like acquiring a large ensemble of specialized instruments, fine-tuning them, and getting them ready to play ever more intricate scores. Development of all of the key characteristics distinguishing humans from other primates — bipedality, manual dexterity, elaborate tool making, intergenerational transfer of technical skills, and higher encephalization — was fostered by our evolution from simple foragers to sophisticated hunters and incipient plant cultivators.” (p 106)
“Although some foraging societies had to spend just a few hours a day to enjoy abundant food supply, other had to cope with recurrent hardships intensified by seasonal food shortages leading to high infant mortalities (and to infanticide) and to often devastating famines. The idea of foraging existence as the original affluent society is clearly an impermissible generalization.” (p 108) I assume he is referencing Marshall Sahlins here.
“Explanation of cattle’s traditional usefulness lies above all in their energetic advantage: as ruminants they did not create any additional demand for feed grains grown on good farmland. They can extract sufficient nutrition just from grasslands and crop residues, with occasional supplementation by such crop processing by-products as milling, or oilseed-pressing wastes. Even densely populated Asian lowlands with extremely limited grazing could thus support large counts of working bovines without reducing food production capacity.
[…]
In contrast, as horses got heavier and worked harder, they needed cereal or legume grains whose cultivation claimed increasing shares of cropland.
[…]
Water buffaloes […] aquatic adaptation allows them to graze while completely submerged, tapping phytomass inaccessible to any other working animal.” (p 113–114)
“During the late nineteenth century American horses were fed four to five kilograms of oats a day, and at the peak of their importance, between 1910 and 1920, at least one-fifth of U.S. farmland had to be devoted to cultivation of horse feed! One well-fed American horse preempted cultivation of food grains capable to sustain about six people — but it could work at a rate at least ten times higher than an average man, offering a substantial energy advantage. But new farm machines required a more concentrated source of power: it was a logistic mess to harness and to guide two or even three dozens of horses pulling grain combines on California’s vast grainfields. Even the early, relatively small, internal combustion engines mounted on tractors or used for pumping water or in threshing, could replace at least ten horses — and do so while claiming no land for fee. The millennium of horse power that built Western civilization came to a rapid end.” (p 117)
Industrial Energy Production
“While human labor could deliver around one hundred watts of sustained power per person, and cattle usually no more than three hundred watts per head, typical roman waterwheels rated around two kilowatts. Corresponding increases in productivity were impressive: a slave could grind about three kilograms of grain per houor, a donkey about ten, but waterwheel-driven millstones could grind up to one hundred kilograms.” (p 122)
“The theoretical capacity of windmills increases with the cube of the wind speed, which in turn is proportional to the height above the ground raised to the power of 0.14. Consequently, for a given wind speed near the surface, a machine with a shaft ten meters above the ground will be only about 60 percent as powerful as one with its axle thirty meters above the ground.” (p 124)
“The high wood demand of medieval and early modern iron smelting created many deforested landscapes. Engand’s early adoption of coke is easy to understand: A single early eighteenth-century furnace consumed annually a circle of forest with a radius of about four kilometers.” (p 127)
“But the growing supply of iron had enormous economic and social effects on the premodern world by greatly improving transportation (horseshoes), building (axes, saws, hammers, nails), kitchen work (cookware, grates) — and warfare (guns, iron cannonballs, better firearms).” (p 128)
“Global estimates of ultimately recoverable crude oil indicate that the production could be sustained at the mid-1990s level for at least 80, and perhaps for up to 120, years. This span could be extended by extracting more costly oils locked in shales and sands. In any case, we will try to use oils as long as possible: their high energy density, easy transportability and convenient storage make them the quintessential energy source for modern fossil-fueled civilization.” (p 141)
“First electric motors in factories were installed to drive shorter shafts powering smaller groups of machines, but the unit drive began to dominate after 1900. Consequences of this change revolutionized modern manufacturing. Gone were large gearings and the friction losses and frequent system outings inherent in centralized power distribution. Unit power supply allowed flexible plant design, and by removing the overhead shaft-and-belt clutter with its noise and accident risks it freed the ceilings for better lights and ventilation, a change resulting in greater workplace safety and higher labor productivity. Additional productivity gains and enormous improvements in the consistency and quality of finished products came from precise machine control, possible with individual electric motors.” (p 157)
“Fortunately there has never been an LNG [liquid natural gas] tanker accident. The explosion of a fully loaded ship would release energy comparable to detonation of a nuclear weapon equivalent to ten Hiroshima bombs.” (p 193)
“Freedom of personal movement gained with private cars has been so addictive because, in Kenneth Boulding’s felicitous analogy, the ownership of this mechanical steed turned even the humblest driver into a knight with aristocrat’s mobility looking down at pedestrian peasants.
The personal and professional mobility conferred by cars has been among the most powerful social forces of the twentieth-century Western world. The freedom of individual movement conferred by cars is extremely appealing — but its cost is rather steep. Although most North American adults spend at least 250 hours a year driving a car, they have to spend 350 hours, or nearly 20 percent of their working time, to earn money for the vehicle’s purchase, and for its insurance, fuel, and repairs.
Economists would point out the enormous contribution of cars to the higher standard of living. Carmaking became America;s leading industry in terms of total product value during the mid-1920, a primacy replicated in every major Western economy after World War II. Huge segments of other leading industries, ranging from steel and rubber to aluminum and plastics, depend on carmaking, and substantial shares of other industrial and service activities, ranging from catalytic oil refining to skiing resorts, woudl not exist without cars. Nor would, obviously, suburbs (now extending into exurbs) and multilane highways. Their construction has absorbed huge amounts of capital in every rich country, and even larger sums will be required for their upkeep.
Environmentalists would focus on the car’s enormous air pollution impacts, and on the car’s enormous air pollution impacts, and on its destructive reordering of urban space. Large concentrations of cars emitting nitrogen oxides, carbon monoxide, and hydrocarbons have brought often acutely damaging concentrations of photochemical smog to most large metropolitan areas. Overall long-term costs (mainly health and crop damage) of this pollution may be as large as the immediate toll of accidental injuries and deaths. Highly traveled roads and freeways have destroyed or downgraded neighborhoods and brought in incessant noise and pollution, all too frequently without increasing typical commuting speeds. And new rapid trains are clearly superior for comfortable intercity travel.” (p 183–184)
“Simple calculations show that extending the rich world’s rate of car ownership to the world’s most populous nations could not be done with existing vehicles: China alone (with 1.2 billion people) would have more passenger cars than the whole world had in 1995, and global crude oil production would have to more than triple to fuel some three billion cars. (p 184–185)
“Nuclear energy would be a phenomenal success bringing unimagined benefits for the greater part of humanity; it would provide half (or about 750 GW) of the U.S. electricity generating capacity, and similar shares in other affluent countries; nuclear tankers and explosives would be widely used, nuclear-propelled spaceships would ferry men to Mars and energy from nuclear fusion would be well on its way to commercialization. A generation later none of this has come to pass, and the retreat of nuclear generation has been almost certainly the costliest technical miscalculation of the twentieth century.” (p 152)
“Fixing the environmental damage done by decades of nuclear weapons production will cost hundreds of billions and both the United States and Russia had weakened their economic well-being by investing trillions in an arms race producing ever more expensive but still only ephemeral deterrents. We will never know the exact figure, but the development and deployment of nuclear weapons and associated delivery systems has consumed at least one-tenth of all commercial energy used worldwide since 1945.” (p 173)
The Rickety Thesis
If someone wrote a book about money as the universal solvent in which they compared how much various things cost — pastries and train cars and billboards on the highway — across time and charted cost reductions and income gaps, would this convince you of something?
Would it mean that money always matters? That there is a unity, across all the examples?
Or would it be no more than the sum of its parts? Just a long list of examples, a very long tour through other peoples’ back yard?
I believe that this book, while fulfilling my needs for majesty and sparkly curiosity, has no real thesis and does not make an actual theoretic contribution. At best, it shows a method that is quite powerful when wielded by this particular author.
Vaclav Smil is incredibly authoritative on these topics and I see how well he has positioned himself, in his bizarre and far-reaching method, to make creative comparisons and predictions. But I don’t really believe that his form of energy economics is helpful for many questions. In particular, nothing I was wondering about before reading the book became clearer after reading it.
I still feel that most of what matters with energy is the context around it. If a tree falls in the forest, that may be quite significant, but the amount of energy expressed in its fall is, by itself, generally not important to me.
We might imagine that this very neutral term is itself an important accomplishment. The ability to compare a tree’s fall to an engine’s roar to a cat’s leap is a technology that lets us do new things and make meaningful comparisons we could not before.
But this technology is not equally applicable in all cases, and, for most of the things I do, this comparison is not important at all. May you feel differently!
Regardless of thesis, this book provides more fantastic bits of reality than anything else I’ve read this year, and that is quite an accomplishment.
