Energy: A Beginner's Guide
Preview
Our continuous need for energy has the potential to bankrupt the planet and threaten our very existence. Vaclav Smil helps us discover what Energy is, and how it shapes us and everything around us.
About the Author
Vaclav Smil is a Czech-Canadian academic and a Professor Emeritus at the University of Manitoba. He is considered to be one of the foremost minds on the issue of energy and its implication in public policy. He has written several books including Energy and Civilization: A History, and Natural Gas: Fuel for the 21st Century.
The Big Idea: Discover the science behind Energy, and learn why we must reduce our reliance on conventional energy sources to save our planet
The Greek philosopher Aristotle coined the term Energeia in his philosophical work: Metaphysics. While the word Energeia was adopted by the English-speaking world and modified to "Energy," the true meaning of it was not worked on for nearly 2000 years after Aristotle's coinage.
The lack of insight into the concept of energy did not stop human beings from harnessing it and using it to further their civilizational growth. From the first fires which helped us cook our food and provided us warmth, to the new age climate-control devices and cooking gas; energy has been omnipresent in our lives.
Post the industrial revolution, and particularly in the last 100 years, our over-reliance on conventional sources of energy has led to a situation wherein our existence is under threat.
In this quid you will learn:
How energy has fuelled our progress as a species
Why there are no Rhino Sized Tigers
Why we must find alternative energy sources
What is Energy?
Energy is one of the most misused words in the English language. How many times have you heard someone say that he or she feels energized after a workout? Scientifically speaking it is impossible to feel energized after a workout, without eating or drinking anything. However, figuratively, the use of the word energy can be quite flexible.
The real understanding of energy started coming about from the seventeenth century onwards. Energy is the only truly immortal in our universe. It can neither be created nor destroyed, but can only be transformed to other forms, or transferred to objects or matter. For example, the electromagnetic energy of the Sun's rays can be transformed into heat energy. An electric supply (electrical energy) can move (mechanical energy) an electric motor.
Even the great Richard Feynman observed that Energy is somewhat tricky to define and understand and that it is more of an abstract concept. It can be practically understood as the capacity to do work. The thing to grasp is that work is being done almost all the time! Even when you are sitting still, your body is still processing food; blood is flowing through your veins, your metabolic pathways are still burning energy, that is, work is still being done!
While energy is always conserved in a closed system, that is, a system with no external supply of energy, the availability of useful energy decreases with time. This is the second law of thermodynamics which states that for any closed system, the entropy-which is the state of disorder, always tends towards a maximum.
The third law of thermodynamics formulated in the early 20th century states that a state of static entropy can exist only at absolute zero. In layman's terms, it means that all chemical, biological, or nuclear processes cease at a temperature of negative 273 degrees Celsius.
Solar and Geothermal energy make the Earth livable
All of us know how important the Sun is for life on our planet. However, in reality, it is extremely unlikely for a planet orbiting a star to have an environment suitable for the origin of life.
The Sun and the Earth happen to hold a unique place in the overall scheme of things. The Earth is at the right distance from the Sun. The Sun itself is neither too big, nor too small, but just right with the right kind of luminosity to provide warmth and energy. Venus, for example, is similar to our planet in terms of size, but is too hot, as its closer to the Sun. Mars, on the other hand, is too far, and too cold for life to originate.
The Earth's atmosphere allows the Sun's rays to reach the surface and provide warmth. However, the heat could easily have been reradiated back into space, were it not for greenhouse gases that trap some of the radiated heat. Without the primary greenhouse gases: Carbon dioxide and water vapor, the average temperature on Earth would have been negative 18 degrees Celsius. Too cold for liquid water, and thus, to support life!
Similarly, deep down, the geothermal energy contained within the earth's crust, is responsible for shaping geography. The core of the Earth is gradually cooling molten iron, and the energy it releases intermittently, by way of plate tectonics, magma eruptions, etc., shapes the geography of the planet, and manifests oceans, continents, mountains, rivers, etc.
The power of this energy is visible in events like Volcano explosions and earthquakes. It is estimated that on average 5-6 centimeters of the new ocean floor is created by cooled magma every year. The landmasses which support human and animal life and the oceans which support millions of aquatic species, would not have been made possible if it were not for geothermal energy.
The abundance and proliferation of life forms is a function of the energy available to them
All organisms need energy to live. The set of processes by which an organism converts energy into a usable form to sustain life and grow is called metabolism. Despite the incredible diversity of life on Earth, there are fundamental commonalities in the metabolic pathways, which utilize energy to convert simple inputs into biomass and forms of energy to sustain life.
There are life forms like plants (phototrophs), which use Solar Energy along with atmospheric carbon dioxide and macronutrients from the soil, to produce ATP (adenosine triphosphate) to sustain life processes and to produce new biomass. Then some organisms do not need light like nitrifying bacteria (chemotrophs). These organisms use carbon dioxide and oxygen along with simple inorganic compounds like ammonia to sustain themselves.
Amongst the higher life forms(heterotrophs), there are broadly four types of organisms classified by what they eat for sustenance: Herbivores (Those who eat plants), Carnivores (those who eat other organisms excluding plants), Saprovores (those who eat the meat of the dead), and Omnivores (those who eat everything).
The farther an organism is to the primary energy source (solar energy, geothermal energy), the less is energy available to it. Hence, it is easy to see why plants are much more abundant than animals, and herbivores are much more abundant than carnivores.
Metabolism determines various physical traits which organisms display
Metabolism fuels life. The Basal Metabolic Rate (BMR), or the energy expenditure at rest, is the benchmark for calculating the energy needs of an organism. Its value places limits on certain physical traits which an organism displays.
The BMR is a function of the body mass of an organism raised to an exponent which varies depending upon the eating habits of an organism. Most herbivores, for example, have a metabolic exponent of nearly 0.75, while a carnivore like a Tiger has an exponent value of nearly 0.9. What this means is that the BMR increases disproportionately more with increasing body mass. Therefore, it is nearly impossible to have a Tiger which is the size of a Rhinoceros ( in body mass), since its BMR would be through the roof and hence its life would not be sustainable.
The metabolic scope which is the ratio of short-term energy expenditure and the BMR indicates the performance potential of organisms. While wild hares have a scope of 8, despite being quick runners, Wolves, and other canids, have a scope of nearly 30, which gives them the ability to run strongly for long distances. They are some of the best endurance runners in the animal kingdom.
Human civilization and progress are due to the harnessing of energy
All human progress is a result of harnessing and utilizing energy efficiently. Human beings need three principle macronutrients: Carbohydrates, Fats, and Proteins. They also need micronutrients like minerals and Vitamins to be able to live healthily. Human metabolism consumes these nutrients from food sources ranging from plants, vegetables, and dairy, to non-vegetarian fare including eggs.
The Brain, Liver, and muscles are responsible for the maximum energy expenditure, followed by the heart and other vital organs. While Humans are limited by their somatic capabilities, our energy fuelled brain is a tool that is unmatched on Earth. Our brains which are energy cost centers can amplify human capabilities by leveraging external things like tools, or animals.
From a society of foragers, we became hunter-gatherers due to our ability to formulate and use hunting tools. Such tools magnified our physical ability and helped us have access to more energy (food). As settlements became bigger, and agriculture took root, the domestication of cattle helped us in large-scale farming; an impossible task had we relied solely on our labor.
The proliferation and success of agriculture laid the foundations of the very first civilizations. Gradually over time, we kept refining the means of harnessing energy, and from a simple waterwheel that utilized the energy of flowing water to perform tasks like milling flour, to the internal combustion engines that use an energy source which is the result of millions of years of geothermal forces acting upon the remains of biomass, our progress has been fuelled by accessing energy in new and more effective ways.
Energy is omnipresent in our day to day lives
Our homes have become comfortable because of electricity. Nearly two-thirds of electricity is generated by thermal power plants, and the remaining is produced by nuclear reactors, as well as windmills and solar power plants.
The mobility of people has also increased manifolds because of improved transportation due to refinements in technology fuelled by energy. Everything you do, right from using your cell phone, sending out an email to a client, hosting a barbeque, everything needs energy in some form or the other.
It is not just people who have increased mobility, energy, too, is mobile because of widespread international distribution networks. The petroleum you use in your car in India is a refined version of crude oil that was extracted in the Middle East.
Most crude oil is transported from the Middle East, Latin America, and Russia to most parts of the world. The desire to control energy sources for improved access and availability can lead to conflicts between nations which can cause widespread destruction.
The basal metabolic rate determines the minimum energy we need to stay alive. But, to live a healthy life and be able to engage in physical activities, we need far more energy. However, the modern industrial society with its excessive consumption-oriented outlook produces far more food than is necessary. This is true even when there are pockets of malnourished population in the world.
People in affluent countries eat on an average of only about two-thirds of what is produced. Thus, resulting in enormous wastage of food energy. As we will see in the next section, our excessive use of the conventional energy sources of the planet is threatening our very existence.
Our dependence on conventional sources of energy is bankrupting the planet
For most of our existence as a species, we have relied on forms of energy that were very close to the primary energy source of Solar Radiation. For example, flowing water or wind. While the crops we harvested were a product of a few months of accumulation of solar radiation, the animals we hunted and ate were a product of a few years of harnessing the primary energy source. However, in our modern industrialized society, our energy needs are so immense, that we have to rely on other sources of energy, which are the result of millions of years of geological processes.
These days we are dependent primarily on two types of energy sources: Fossil Fuels, and Electricity. Our dependence on fossil fuels, which are dead and decayed biomass, acted upon by geological forces for millions of years, is leading us to wipe out millions of years of accumulated energy capital, in a short amount of time. Electricity, on the other hand, is a form of energy that we generate by burning fossil fuels, or by harnessing the power of the wind( that is windmills), water(hydropower), and nuclear energy.
While earlier with our reliance on animals and rudimentary use of the elements to harness energy was a sustainable practice, modern usage of energy and reliance on fossil fuels is unsustainable in the long term, since we are quickly bankrupting the planet of energy sources (within the next 100 years) which it took millions of years to make!
It is crucial to discover and harness alternative sources of energy
While it is futile to make a long-term forecast, we must reduce our reliance on fossil fuels. Given the rate of growth of our civilization and the rapidly increasing energy needs owing to the fast-paced development of nations like China and India, we need to focus on discovering and inventing newer forms of energy.
Renewable energy sources like Wind, Solar power, and water, are not enough to sustain the growing needs of energy. Nuclear energy holds much promise. We need to work on better public acceptance of nuclear energy because even though it poses some dangers, it is a clean form of energy that poses no threat to the ecosystem if produced in a secure environment with proper safety regulations and procedures in place.
The innovations and technological progress cannot be predicted, and as such there may be newer ways invented to harness energy without leaving much of an ecological footprint. Such an energy transition will probably take time to take effect. However, with a track record of constant innovation and relentless progress, we should feel reasonably confident in our capability to handle the challenges of the future.
Final Summary
We hope you enjoyed this quid on Energy: A Beginner's Guide. Vaclav Smil takes us on a fascinating journey that helps us discover what energy is, and how it is at the center of life itself, leave alone progress. The energy needs of an organism place real limits on physical traits and performance in the natural world. Human progress too has been made possible by harnessing energy in various ways, starting with domesticating animals, to the industrial revolution, which led to increased automation by using sources of energy like heat, electricity, and nuclear power.
Our insatiable needs are responsible for disproportionate growth and have placed an enormous strain on the conventional sources of energy, which have served us well till now. However, our over-reliance on these sources has also led to environmental challenges which threaten the entire ecosystem. Hence, we must discover and utilise alternative and renewable sources of energy to fuel our growth.
Comments
Post a Comment