====== The K-index ======

**A live planetary energy metric: where humanity actually stands on the Kardashev ladder, computed from data.**

Back to [[k1:kardashev_one|the project hub]].

===== Definition =====

    K = (log10(P_avg in watts) − 6) / 10        (Sagan 1973)

P_avg = world total energy supply per year ÷ seconds in a year (1 TWh/yr = 1.1408×10^8 W average). K = 1 ⇔ 10^16 W ⇔ 10,000 TW average. Every +0.01 K = +26% power; every +0.1 K = ×10.

===== The current value =====

**K = 0.728 (2025)** — world total energy supply 600.3 EJ (Energy Institute Statistical Review 2026, via Our World in Data) ⇒ 19.02 TW average power.

  * Basis disclosure: EI dropped its substitution method in 2025; on the older substitution basis the remaining climb reads ×526–×560 instead of ×525, and K = 0.725–0.728. We print the current basis and the spread.
  * Data: OWID grapher ''primary-energy-cons'' (CC BY — attribution: Our World in Data / Energy Institute; Smil pre-1965).

===== The series (world, selected years) =====

^ Year ^ TWh/yr ^ Avg power ^ K ^ Note ^
| 1800 | 97 | 0.01 TW | 0.404 | wood, water, muscle |
| 1850 | 569 | 0.06 TW | 0.481 | coal era begins |
| 1900 | 5,990 | 0.68 TW | 0.583 | |
| 1950 | 20,472 | 2.34 TW | 0.637 | postwar boom starts |
| 1970 | 54,921 | 6.27 TW | 0.680 | fastest K climb in history |
| 2000 | 105,981 | 12.09 TW | 0.708 | |
| 2010 | 136,245 | 15.54 TW | 0.719 | |
| 2020 | 147,985 | 16.88 TW | 0.723 | the stagnation decade |
| 2024 | 164,494 | 18.77 TW | 0.727 | matches EI 592 EJ ✓ |
| 2025 | 166,754 | 19.02 TW | **0.728** | current value |

Milestones (annual data from 1965): **K=0.60 in 1910, 0.65 in 1960, 0.70 in 1988, 0.72 in 2011.** The 0.6→0.7 decade took 78 years at 2.5–3.3%/yr growth; the same log-distance at 1%/yr would take ~230 years — the rate, not the physics, sets the calendar.

===== Per-country (v2) =====

  * Only **3 countries ≥ 1 TW**: China 5.14 TW (max national **K = 0.671**), US 2.97, India 1.24 — every polity is sub-planetary.
  * **China-2025 = world-1967** in energy terms (162.2 EJ vs 163.7 EJ) — the energy time machine.
  * Top-10 countries = **69.8%** of world energy; per-capita spread **×64**; **32% of humanity below 1 kW/person**.
  * China = **42%** of world energy growth 2024→25.

===== Sources and mirrors =====

Master files: ''knowledge/04'' (world series) and ''knowledge/08'' (per-country) in the project repo; the appendable public mirrors are linked from the [[k1:kardashev_one|hub artifact table]]. Corrections welcome in any mirror's APPEND LOG.