The amount of energy we consume

Human being relies on energy in daily life. Our lives cannot be described without mentioning energy. Have you ever considered how much of energy we consume?

This post addresses the amount of energy we consume, and the amount of energy we can use in future.

The primary energy consumption in the world

The figure below summarizes the histric evolution of our primary energy consumption in the world.^[1,2]

* Sorry that the figure is in Japanese, but will be translated into English
1次エネルギー消費量：Primary energy consumption
年：Year
バイオマス：biomass, 石炭：coal, 石油：oil, 天然ガス：natural gas, その他：others

* "Others" in the figure include nuclear, hydro, wind, solar, and so on.

The primary energy means the energy that has not undergone any process or conversion. It includes fossil fuels (such as oil, coal, natural gas), nuclear energy, solar energy, and wind energy among others. Statistics often handles the electric power, which on the contrary is the processed energy, and therefore is not the primary energy.

Our consumption of the primary energy had drastically started rising at the point of industrial revolution in 18th century. The value of our primamry energy consumption almost reached 5 *10²⁰ [J]. It is too big to understand, isn't it? It mostly is composed of coal, oil, and natural gas.

The energy souce that we can use

We have leant the total amount of energy that we consume, but how much of energy is left for us? The figure below illustrates the energy left for us, based on the date published by International Energy Agency.^[3]

* Sorry that the figure is in Japanese, but will be translated into English.
全世界・年間のエネルギー消費＝The annual primary energy consumption in the world
地表・年間の太陽光照射エネルギー＝Annual irradiation of sunlight on the surface of the Earth
石油可採埋蔵量＝recoverable reserves of oil
天然ガス可採埋蔵量=recoverable reserves of natural gas
石炭可採埋蔵量= recoverable reserves of coal

In the figure, the size of balls quantitatively corresponds to the amount of energy. The top-left ball describes the primary enregy consumption in the world, which as we learnt above corresponds to apprimately 5*10²⁰ [J].

The amount of fossil fuel are limited. The reserve from which we can economically extract fuels with our available technology, is called the recoverable reserve.^[4] The recoverable reserves of oil or natural gas are roughly 50 years.

On the contrary to the recoverable reserves of the fossil fuel, a ball in a huge size is found at the top-right of the figure. This ball is the energy of sunlight that irradiate on the surface of the Earth annually. I repeat, "annually". Quantitatively, the total energy of sunlight irradiation is 6,000 times greater than our current annual primary energy consumption.

The use of fossil fuel has faced issues of limited reserves and green house gas emission. Without making use of available renewable energy such as sunglight, our primary energy consumption cannot be supplied.

References

1. BP, Statistical Review of World Energy, 2018.
2. Our World in Data, “Global primary energy consumption by source”, https://ourworldindata.org/grapher/global-energy-consumption-source?country=~OWID_WRL (accessed on 2022/02/03)
   ※原典： Vaclav Smil, Energy Transitions, 2017.
3. International Energy Agency, Solar Energy Perspective, 2011.
4. INPEX, “9. 埋蔵量：天然ガスはなくならないの？”, https://www.inpex.co.jp/museum/01/09.html (accessed on 2022/02/03)