We are ~100 watt biological machines
Children per woman
Fertility rates are dropping across nations. Amongst nations with top 10 GDP. India is the only country in top 20 countries by GDP with fertility rate above 2. It’s at 2.05 and may soon fall below 2 as India gets wealthier.
Is that a bad thing? One could argue both ways. An inverted pyramid means more retired seniors than young workers. With less young workers, less is produced.
On the other hand, fewer people would mean more resources per person i.e fewer healthier wealthier people. The fewer people argument only makes sense if we can produce more per person (in a sustainable way).
Let’s look at the world by population
People mostly live in clusters where there is access to water, food and livable land. Notice how large countries such as Canada, Australia & Russia can barely be seen. 60% of the human population lives in Asia.
Now let’s look at GDP per capita & energy consumption per capita.
Countries with abundant natural resources, strong industrial base, educated population have more wealth per capita.
Interestingly the British empire offshoots - United States, Canada, Australia have more wealth per capita than UK.
Energy
The energy problem is two problems. The first is that for humans to have a great quality of life, they need access to energy. The second is that current approach of burning fossil fuels isn’t very sustainable for long term.
What we need is cheap clean dense portable energy sources. We will go deeper into this in another blog post.
Energy moves things. A farm is assembly of water, carbon and other molecules into wheat, corn, beans e.t.c A factory assembles raw materials into finished products. Everything we consume is assembled and transported using energy.
Before the advent of machines, most humans worked with their hands and simple tools. For heat, they burned wood. Then came steam engines. Then came the internal combustion engines and electric motors. At every stage, humans could harness more power.
Ehumans
Let’s dive into some numbers.
1 watt = 1 joule/second.
1 joule = 1 newton force for 1 meter = lift 100g weight by 1.02 meters = heat 1ml of water by 1℃.
An average human consumes about 2000 calories per day. That is about 2.4 kWh/day or 73.2 kWh/month. Average human power consumption is ~100 watts.
A Tour-de-France level athlete could sustain 300 watts for a few hours.
2.4 kWh / day is the important number here. We will treat human-power consumed / day as an energy unit ehuman
.
Let’s compare that energy to common things around us, measured in kWh and equivalent ehumans.
1 horsepower for 1 day = (0.75 kWh * 24) / 2.4 = 7.5 ehumans.
- Average home electricity use per day (Refrigerator, dish washer, TVs e.t.c) = ~1000 KWh/month = (32.8 kWh/day) / 2.4 = 13.6 ehumans.
- Average car gasoline consumption (1 gallon gasoline = 33.6 kWh) = ~40 gallons / month = 1.3 gallons/day = (43.68 kWh/day) / 2.4 = 18.2 ehumans.
- Boeing 777/747 flight for 24 hours (1 gallon jet fuel = 37.54 kWh) = ~5,000 gallons of jet fuel/hour = 120,000 gallons/day = (4,504,800 kWh/day) / 2.4 = 1,877,000 ehumans.
At ~500 passengers, we’re still looking at 3,754 ehumans per passenger. Flying is energy hungry. ~60% of a flight ticket is the cost of fuel. One of the reasons why we don’t have flying cars yet!
In terms of energy prices as $/kWh in US.
Electricity = ~$0.15/kWh. (energybot.com/electricity-rates)
Gasoline / gallon = ~$3.30 / gallon = $3.30 / 33.7 kWh = $0.10/kWh
Jet fuel / gallon = ~$5.25 / gallon = $5.25 / 37.54 kWh = $0.14/kWh
Food expenditure = ~$300 / month = $300 / 73.2 kWh = $4.10 kWh
Human energy input as food is ~40x more expensive compared to equivalent gasoline energy, and ~30x expensive compared to electricity. Gasoline is cheap, volume dense, weight dense, easy to store and transport. That is why we are addicted to it as an energy source.
Let’s compare energy use per capita in Somalia vs United States
United States = ~80,000 kWh/year/person = 219.18 kWh / day = 91.3 ehumans.
Somalia = ~200 kWh/year/person = 0.54 kWh/day = 0.2 ehumans.
In other words, average American has 91 other human energy equivalents working for them. (Imagine you have 91 human-sized hamsters running on a hamster wheel to produce energy for you), while a Somalian is mostly using their own muscles.
If we take into account the human population + ehuman population by country, this is what the top 10 countries look like.
China + US + India + Russia is > 100B population.
Whether human consumed food like pizza and rice is oxidized for energy by humans, or fossil fuels are burned for energy, energy is energy and equivalent amount of CO2 is produced from both.
Connecting this to fertility rates, If we only look at human population, most developed nations have a slow decline in population. If we take into account total human + ehuman population, it is growing.
Imagine this, when a baby is born in a modern economy, there are ~30 other invisible ehumans babies born to server that one baby.
The economic argument for robots
Imagine we build a 100 watt electro-mechanical robot (A physical ehuman). It Suppose it has similar dexterity of a humans body. A 20 watt processor with equivalent general intelligence to a human brain.
How much would the energy input as electricity cost? Let’s say we only turn it on for 40 hours/week akin to a human.
100 watts * 40 hours = 0.1 kW * 40 = 4 kWh.
Electricity cost at ~$0.15 / kWh = $0.6. 60 cents!!!! for a whole week. $31 for the whole year.
Currently we have no general robots that can do basic cooking, cleaning, laundry duties in the house. Current generation of robots are quite expensive and can only work in fixed environments. There are some fixed arm robots in warehouses. We’ll dive deeper into intelligence in a separate article.
From a physics and economic perspective, the price of labour will keep on dropping close to the price of energy with gains in automation.
Humans are a special species because we are intelligent enough to build tools. Tools that allow us to harness external energy and materials to build things. Some of the things we build, can build things, which can … build more things. Fascinating!