There are certain principles of physics the general public may not understand the nuances of, but we get the concept. Gravity being one. How all objects fall, why something moves down, not up, an incline. Force is another one. An object with more mass, or an object moving faster, has more force. We get that.
There are others not in the general public’s discourse. What percentage of the population has a general gist of energy? Sure, we get energy helps us do work, but there is another basic tenet of energy the physics community, or those who write about it, haven’t gotten across for the rest of us. Namely, a byproduct of energy production is heat.
The laws of thermodynamics don’t seem to be taught until higher level physics. Maybe sophomore year of college or so. It’s a small amount of people ever reaching that level of classes.
- First Law: Energy cannot be created or destroyed. Only converted from one form to another.
- This might sound familiar for many of us.
- Second Law: The entropy of the universe increases.
For the second law, it’s like, uh, what? These statements make the second law make more sense though:
No system can perfectly convert energy. There is always a byproduct.
We have an equation for the efficiency of a heat machine:
- n = 1 – Tc / Th
We want to get a number where n = 1, meaning 100% efficiency. In order for that to occur, the environment’s temperature, Tc, must = 0. (Th = heat within the machine.) That way our equation would be,
- n = 1 – 0 / Th = 1
Tc being 0 is absolute 0, where particles cease to move. When particles cease moving, they have no thermal energy or heat. (Third Law.) Heat is a form of energy.
-> I heard a professor whom I held in high regard, as well as a physiology author I really enjoy, say “if it doesn’t have calories, it doesn’t have energy.” This is not true. Energy does not come in one form ala calories. For instance, water, with no calories, so long as it is not absolute zero, has energy. Water that gets really hot, despite still not containing calories, can do quite a bit of work (energy): steam engine.
Because Tc is basically fixed -it’s hard to make your environment colder- the only way to change the efficiency is to get Th, the heat within something like an engine, higher. Things like using materials which can withstand more heat. This way there is a bigger difference between Tc and Th, and subsequently more efficiency.
But it doesn’t matter if this Th is the sun, where the sun is your energy generator, because Earth, Tc, isn’t going to be 0. (We’re talking solar panels now.) We’ll never get to 1. Absolute zero, no heat, isn’t going to happen. Therefore some heat is always a byproduct of producing energy.
Upon some thought, most of us can grasp this quickly. When we move, we get warmer. If we move even more, we get even warmer. When we cook, things get warmer. Make a pot of coffee, not only does the coffee get warmer, but so does the coffee maker. Drive a car, the engine gets warmer. Drive the car harder and longer, it gets even warmer. Charge our phone, the phone and charger get warmer. Even the back of a fan gets hot. It doesn’t take much to understand using energy = heat. (Although, we might not realize running the AC in Tokyo can make the streets nearly 4 degrees warmer!)
But do we appreciate this when it comes to our overall energy consumption, and what’s going on in the world right now?
We have been remarkably consistent increasing our energy use over time, at 2.9% per year, since 1650. Just leveling off some recently.
People like Elon Musk and Bill Gates are doing great things, but them, Silicon Valley, and many humans in general, or maybe it’s just America, have this love affair with the future. With human ingenuity. With “innovation.” There is no doubt these are smart people, but it does not matter how we meet our energy needs if we continue to increase our energy consumption like we have.
No matter what method we use, the byproduct of energy production is heat. Continuing like we have, in ~200 years, the Earth will have to get noticeably warmer, and then rapidly so after that.
(The above chart assumes the world grows at a similar rate to the historical growth of the United States. If you want details, I’d point you to this Do The Math post (as well as this one), which is by a physicist.)
Note the above may be a best case scenario. It only assumes a 2.3% growth rate, not our historical 2.9%. Nor does the above chart concern itself with the thing we’re currently most concerned with, the greenhouse effect!
Coal, oil, natural gas, hydro, solar, wind, nuclear, geoengineering. In multiple ways, it does not matter.
“A diet soda with only 1kcal is packaged in an aluminum can that required 1600kcal to produce. This estimate does not include the 600 kcal needed to process the 12 oz soda, bringing the total to 2200 kcal for 1kcal of soda (Pimentel, 1984).”
Elon Musk has described how much diet soda he used to drink, and this post from Bill Gates, describes how much diet soda he currently drinks. These are also two guys who could stand to lose a few pounds, take a good amount of private flights, have big houses, etc.
It doesn’t matter how brilliant they are, what inventions they come up with or fund, what partial solutions they’re working on (of which some are certainly great things), they’re part of the problem as much as we all are: Their behavior, human behavior, needs to change. They’re only used as examples because they’re in the spotlight, but this is a common scenario. People on television espousing energy issues, climate change problems, only to have habits which are energy intensive. Weight issues being the most common one. Extra weight on your body is wasted energy.
Even if a solar panel, breaking the laws of nature, was 100% efficient, in 345 years, every ounce of land would have to be covered with solar panels to meet our needs by that point!
We haven’t even discussed how producing solar panels causes greenhouse issues. So far, solar panels have contributed to the CO2 problem. By producing them faster than it takes them to offset their CO2 manufacturing costs, they are net contributors to the problem.
Granted, we don’t know things will continue they way they have been. Certain countries have very low birth rates right now, and if the population levels off, or decreases, maybe this all doesn’t matter as much. (This would fit under changing our behavior as well.) But right now, our behavior is dictating our energy use, and painting a bleak picture if it continues the way it has.
If the population levels off some, then there is no telling we will immediately hit an energy ceiling either. In America, we are continuing to push the limits of how little we can use our own body for energy expenditure in favor of machines. Elon Musk and Tesla now have their cars to where they will open and close the door for you, and are working on the car doing all the driving. The machine does more as we do less. And few countries live the way Americans do. There is plenty of room at the top. There is plenty of room for the rest of the population to expend as little energy as we do in favor of machines expending that energy.
- “hunter-gatherers of a few million years ago used about 1 watt per kilogram
(0.05 kilowatt per person);
- agriculturists of several thousand years ago used roughly 10 watts per kilogram (0.5 kilowatt per person);
- industrialists of a couple of centuries ago used about 50 watts per kilogram (2.5 kilowatts per person);
- citizens of the world today, on average, use approximately 50 watts per kilogram (2.5 kilowatts per person); and
- residents of the affluent United States use around 250 watts per kilogram (12.5 kilowatts per person).
The cause of this recent rise is not population growth; these are power density values caused by the cultural evolution and technological advancement of our civilization.”
(Notice the above values are in watts per kilogram. Not only is society using more energy, but each person is as well. Meaning population growth isn’t the only explanation.)
And it’s not like we have concurrently lessened our energy consumption as our need to expend energy has decreased. We have continued to increase our bodyweight, which increases the energy it takes just for basic function. A heavier person needs more energy to live than a lighter person. A machine has to do more work transporting a heavier person than a lighter person. (This is especially true for airplanes.)
It’s worth harping on the food and drink consumption element of this because
- Nearly 70% of Americans have weight to lose
- 2.1 billion people in the world have weight to lose
- We currently use 10 calories to produce 1 calorie of food (here and here)
- There was a time we used less than one calorie to produce one calorie of food. (Otherwise we would have died.)
- It’s an element benefitting both the individual and our ability to live within the planet. Eating less, drinking less, for most people now, is good for you and everybody else.
Using less air conditioning, changing your job so it’s closer to home, moving so you’re closer to work, getting an electric car, taking public transit, not going on vacation as much, these often involve sacrifices on the individual level. That’s asking a lot of people. Sometimes they are not feasible. An electric car is still an expensive purchase (financially and logistically), and good luck with public transit being your only form of commuting in Southern California.
Losing weight? Drinking less soda? Eating less beef? Changing what you consume? Most people should be doing that anyways, for their own health. Changing calorie consumption won’t be enough, but it’s something, and it seems worth starting with. If we can’t change this, something so obviously positive for our own health, how will we change our transportation habits, which typically involves a personal sacrifice?
200-300 years or so may seem like a while, but at the rate humans currently live (~80 years), in two lifespans people start dealing with this. Those born in 160 years, halfway into their lives, they’re in the midst of this. Abraham Lincoln is still consistently referenced in pop culture. He was around 160 years ago.
The energy we put down our throats now may be energy your not too distant relatives don’t get to use. Not only because of a potential lack of innovation, because you had to take the only job you could, because you had to live in Arizona, but because of what and how much you put in your mouth.