A History of Energy Flows

From Human Labor to Renewable Power

Anthony N. Penna

• Publisher: Routledge
• Year: 2019
• ISBN:
  9780429960734
• Edition: 1
• Topic: Biological Sciences
• Subtopic: Ecology
• Index: Biological Sciences

This book presents a global and historical perspective of energy flows during the last millennium.

The search for sustainable energy is a key issue dominating today's energy regime. This book details the historical evolution of energy, following the overlapping and slow flowing transitions from one regime to another. In doing so it seeks to provide insight into future energy transitions and the means of utilizing sustainable energy sources to reduce humanity's fossil fuel footprint. The book begins with an examination of the earliest and most basic forms of energy use, namely, that of humans metabolizing food in order to work, with the first transition following the domestication and breeding of horses and other animals. The book also examines energy sources key to development during the industrialization and mechanization, such as wood and coal, as well as more recent sources, such as crude oil and nuclear energy. The book then assesses energy flows that are at the forefront of sustainability, by examining green sources, such as solar, wind power and hydropower. While it is easy to see energy flows in terms of "revolutions, " transitions have taken centuries to evolve, and transitions are never fully global, as, for example, wood remains the primary fuel source for cooking in much of the developing world. This book not only demonstrates the longevity of energy transitions but also discusses the possibility for reducing transition times when technological developments provide inexpensive and safe energy sources that can reduce the dependency on fossil fuels.

This book will be of great interest to students and scholars of energy transitions, sustainable energy and environmental and energy history.

Part I

The organic energy regime

1 Biological converters of energy

Food, fodder and firewood

Introduction

At the end of the world’s last Ice Age in approximately 11,600 BCE, global populations did not exceed 10 million people. As the most recent current warming stage in human history, scientists and historians refer to this epoch as the Holocene. Prior to this warming period, the sequence of human evolution, however unclear, proceeded from Australopithecus africanus to Homo habilis. Further evolutionary history followed with Homo erectus, appearing about 1.7 million years ago. This hominid species left Africa in successive waves through Southwest Asia, populating significant portions of the Eurasian landmass. Each of these hominid species either disappeared or continued their evolutionary cycle. Homo sapiens, our ancestors, evolved from Homo erectus and began its migration out of Africa approximately 150,000 to 200,000 years ago. All previous species of the genetic type, Homo, lived a nomadic life as hunter-gatherers, moving constantly in search of eatable plants and animals. Uncooked food sustained these archaic humans and remained their only source of energy for millennia.

Humans metabolizing food into energy in order to work dominated the production of energy for most of human history before the domestication and breeding of horses and other animals. This change was gradual and inconsistent in the world. Many people continued to cut down trees for fuel, hew logs for construction and seed fallow ground without the benefit of animal energy for centuries after domestication – and eventually industrialization and mechanization – were common in parts of Europe and Asia.

The transition from human and animal labor continued for centuries, even as a more efficient fuel source, wood, provided opportunities for the invention of machines that could dwarf the human–animal potential for energy creation. While people today tend to see energy transformation and creation in terms of “revolutions,” this energy transition took centuries. In spite of the commonly held assumptions about energy and the Industrial Revolution, the invention of machines for manufacturing and industry were not run on wood’s eventual replacement, coal. Wood-powered engines built the factories and mills that housed machines and wheels that harnessed the kinetic energy of rivers and the vanes that caught the energy of winds.

The discovery of fire

The discovery and control of fire by Homo erectus, dating back at least 500,000 years represented the first great ecological transition for humans, influencing their evolutionary trajectory. “The discovery of fire and the exploitation of draft animals marked two main changes in the history of technology.”¹ Although scant evidence exists about how this discovery and use were made, watching naturally occurring fires caused by volcanic eruptions and falling rocks may provide some of the circumstantial evidence.

One hypothesis developed by interpreting the fossilized remains of large predators in a cave in Sterkfontein, South Africa, suggests another way in which humans gained control over their environment. For many generations, big cats, possibly saber-tooth tigers, much larger than today’s Indian tigers, feasted on Australopithecus africanus, who had not mastered control of fire. Then, Homo erectus arrived on the scene, reversing the age-old tradition of predator and prey.

Another hypothesis put forth by researchers suggests that by possessing the ability to hold a stick and by poking through a fire looking for food, Homo erectus learned that sticks in a fire promoted burning. So, adding more sticks kept the fire burning, and carrying a fire stick allowed them to set fires on their own. Keeping and maintaining a fire required planning, the help of others and the expenditure of energy to collect sticks and other combustible biomass sometimes by walking a fair distance. Thinking and cooperation became essential ingredients for success.

The use of fire provided early humans with the ability to cook their food. Cooking made both animal parts and vegetation more digestible and nourishing. Although we do not know how this transition to cooking occurred, recent evidence suggests that cooking meat led to increases in brain size and human intelligence. With climate change and rising temperatures, early cultivators used fire as a readily available energy support to light the darkness. It deterred predators, burned away destructive vermin and cleared the land. By engaging in these activities, they unknowingly fused nitrogen to the soil and improved its productivity. Many energy supports followed including the domestication of animals and their use in farming and for transport. The invention of the plough, the wheel, the cart and much else accelerated the transition from human to animal energy for work. Population growth became one of its unintended consequences.

The spread of “fire-stick farming” gave humans a readily available tool for clearing the land for cultivation, killing off vermin that spread disease, and hunting. It may also have been used to deter competing humans from invading one’s food and shelter. Although the use of the fire stick improved their technical capabilities and health, physical stature and social structure, it increased their ability to convert cooked food into work. Despite this transformation, for a little less than 90 percent of human history, food was the only source of energy for humans, with fire representing 9 percent and working animals, 1 percent.² The remainder was animals, water and windmills. All these percentages would change with the transition from gathering and hunting to cultivation and early agriculture encouraged by the warming climate of the Holocene.

In the meantime, the early land practices of Homo sapiens

had profound impacts not only on the fire regimes but also on the landscape vegetation pattern and biodiversity. Commonly, woody, closed-canopy shrublands and woodlands were opened up or entirely displaced by fast-growing annual species. They provided greater seed resources and planting opportunities. These changes also had cascading effects on ecosystem function. In fact, fire-stick farming was probably necessary not only to open up closed-canopy woodlands to create habitable environments but also to reduce catastrophic fires that would pose a risk to humans.³

Along with thought processes and social interaction associated with getting and maintaining control over fire, cooking around an open fire unleashed higher food energy. It provided Homo erectus with the energy to travel farther, out of Africa into Southwest Asia, with a greater capacity for work and a fitness advantage over other archaic humans. Stored cooked food, a new feature, suggested a plan for distribution within a group. Gathering around fires for eating and socializing, as well as using fire to fend off predators, may have encouraged group cohesiveness.

Some scholars suggest that cooking with fire may have stimulated the development of bigger brains and bodies, smaller teeth and leaner limbs that prompted easier mobility and the social development mentioned earlier. Cooking may have extended the lives of these early humans. Using fire extended their home range into colder regions of Eurasia and allowed them to use the energy of fires to alter their surrounding environments. New social organizations, including the suggestion of a “grandmother” hypothesis regarding the nurturing of children, released parents for other productive activities.⁴

For archaic humans, the primary energy source derived from their labor of gathering and scavenging and then transitioning to overhunting large megafauna and eventually smaller mammals. They consumed nuts, fruits, grains, edible vegetables, animal flesh and fish, converting the food into the energy for work. Food is to humans and animals what gasoline is to mechanical engines. The major difference between humans and machines, however, requires humans to expend energy in search of the food that they need to survive. Archaic humans spent the majority of their waking hours securing the food that they needed to survive. If they failed in this quest because of injury, poor judgment, an inferior skill set or environmental conditions, they died.

Over time, successful technical innovations, including throwing projectiles, such as clubs, sharpened spears, bows and arrows, and strategies for corralling prey for the kill increased efficiency. At the same time, overhunting and burning off the vegetation to make the hunt more successful could alter the environment in fundamental ways. Regardless,

their food base remained very limited and populations were therefore extremely sparse. As with animal species, moreover, there were often major seasonal fluctuations in the quantity and type of food available for consumption, and the size of the population which could be sustained was further limited.⁵

Throughout much of Homo sapiens’ early history, Earth’s climate 120,000 years ago was warm, suggesting an abundance of food and fiber. As the climate cooled in anticipation of the last great Ice Age that lasted for about 90,000 years with intermittent warming phases, Homo sapiens migrated out of Africa into the more temperate region of southwest Asia. By 50,000 years ago, they reached New Guinea and 40,000 ago settled in Australia. Extending their nomadic range to Siberia, they crossed the ice-covered Bering Straits 20,000 years ago and began their movement southward into the Americas.

Throughout this long evolutionary history, the human population remained relatively small, numbering no more than 1 million persons 100,000 years ago. Despite its size, however, megafauna collapse followed the encroachment of humans. As geographer Jared Diamond has pointed out, the North American Plains 15,000 years ago looked like the African Serengeti Plain today, with “herds of elephants and horses pursued by lions and cheetahs, and joined by members of such exotic species as camels and giant ground sloths.”⁶

The invention of agriculture

The invention of agriculture in multiple locations around the world during the warming of the Holocene resulted in an increase in the global population. At its beginning, in 11,600 BCE, approximately 4 million people inhabited the planet. Between that date and 5000 BCE, another 1 million people inhabited the planet. Population growth accelerated from the 5 million noted earlier to 15 million in 3000 BCE and to between 170 and 250 million in 1 CE. Later, humans would make the transition to a new energy regime. As water and windmills became available in limited quantities, they represented the only nonbiological sources of mechanical energy.⁷

With the onset of the Holocene 11,600 BP, humans experienced a changing climate with rising temperatures. With global carbon dioxide reaching 280 parts per million, an important milestone in plant growth, humans began to cultivate edible plants. Through a protracted and uneven sequence of experiences, cultivation replaced gathering. The age of agriculture encouraged settlement; the development of a common language, rituals and rules; and the beginnings of social hierarchies.

Despite the approximate 200,000-year history of Homo sapiens, global warming and the human invention of agriculture became prerequisites for the development of civilizations. Human settlement, rather than lives on the move in search of food, led to the development of institutions over long historical periods that possessed many of the characteristics that we identify today as political institutions, systems of monetary and economic exchange and social hierarchies and norms.

Human energy from food

Throughout this long history, humans converted caloric energy into work, inefficiently for most of its history, despite improvements in their physical and technical capabilities. What we do know is that a person receiving 3,500 calories of food...

Table of contents

• Cover
• Half Title
• Title
• Copyright
• Dedication
• Contents
• List of figures
• Introduction and acknowledgments
• Part I The organic energy regime
• Part II The mineral energy regime
• Part III The renewable energy regime
• Part IV Alternative energy solutions
• Index