Kardashev scale

The Kardashev scale is a method of measuring a civilization's level of technological advancement, based on the total energy usage of a civilization. The scale is exponential and hypothetical and regards energy consumption on a cosmic scale. It was proposed in 1964 by Nikolai Kardashev and modified in 1973 by Carl Sagan, which is the scale we use.

Carl Sagan defined intermediate values (not considered in Kardashev's original scale) by interpolating and extrapolating the values given for types I (1016 W), II (1026 W) and III (1036 W), which would produce the formula K=(logP-6)/10 where K is a civilization's Kardashev rating and P is the power it consumes, in watts. Using this extrapolation, an early Type 0 civilization, not defined by Kardashev, would consume about 1 MW (106 W) of power.

A toe is a "tonne of oil equivalent" which is 42 gigajoules and 1 Mtoe = 11.63 TWh (terawatts per hour).

Humanity's civilization type as of 1973 was about 0.7, using 7 101.3 Mtoe = 82 588 TWh arriving at an average hourly power consumption of 10 terawatts (TW).

Total Mtoe is primary energy found in nature and not yet engineered. It is all non-renewable and renewable, comprised of oil, coal, gas, minerals for nuclear power, solar, wind, hydro, biomass and geothermal. This total is used to calculate the K-rating.

In 2018, the total world energy consumption was 14 421 Mtoe = 167 716 TWh for the year. The calculation is 167716 / 365 / 24 to get an average hourly power consumption of 19.14 TW. The final calculation is (log 19 140 000 000 000 - 6) / 10 to make 0.73 on Sagan's extended Kardashev scale.

2018 data sources from International Energy Agency (source 1 and source 2) and original source.

2019 data is 583.9 exajoules = 162194.44 TWh.

2020 data is 556.63 exajoules = 154619.44 TWh.

2021 data suggests 17.7 TW. The final calculation is (log 17 700 000 000 000 - 6) / 10 to make 0.72.

2022 data suggests a 6% increase from the previous year. The final calculation is (log 18 760 000 000 000 - 6) / 10 to make 0.727 which takes us back to .

EIA projects nearly 50% increase in world energy usage by 2050. This is about 29 TW which approaches 0.75 on the Kardashev scale in 2050.

Freeman Dyson calculated in 1959 that if mankind's Malthusian (exponential) growth rate in energy consumption were to continue, the human race would reach a crisis point within the next two to three millennia. At this point, all the non-renewable sources would be exhausted, and even renewable sources exploited on a planet-wide scale would be unable to cope with further demand. To provide for future growth, the human race will need to capture much more of the Sun's light with a Dyson sphere.

Michio Kaku suggested that if humans increase their energy consumption at an average rate of 3% each year, they may attain Type I status in 100–200 years, Type II status in a few thousand years, and Type III status in 100,000 to a million years.

An entropy limiting factor should also be considered in an adjustment to the scale. An advanced civilization will be able to perform vastly more tasks with less energy than we use today, and far less wastage due to friction.

A pessimistic estimate from Xenology is as follows:

If the historical 3% growth rate is maintained, then by the year 2300 mankind's energy budget will be up to 2 x 1017 W, which is also the total power received from from the Sun to Earth. We will then face the most critical "energy crisis" in the history of Earth. All forms of energy (electrical, thermal, mechanical, nuclear) ultimately returns to the biosphere as heat, causing the global temperature to rise and the precarious energy balance of the biosphere begins to suffer irreversible damage. By the time artificial energy production equals total solar influx, the planet will have suffered serious ecological damage. Earth would no longer be inhabitable by humans, our lush green world converted into a stewing, steamy hellhole like Venus.

A safe level is likely the photosynthetic energy limit, or the total solar energy used by green plants worldwide which is about 4 x 1013 W. Using 1% of the total solar influx (1015 W) would be a critical limit, sufficient to melt the polar icecaps and thoroughly disrupt the entire ecology.

"We estimate, therefore, that the maximum upper limit of artificial energy generation for any Type I planetary culture limited to a single world in our galaxy is roughly 1015 watts".