Where the energy actually goes
From what we dig up, to what crosses the meter, to what a machine turns into
something useful. The chain stops at useful energy: beyond it no efficiency is
definable — a perfectly insulated building would need no heat at all, which would
make its efficiency infinite.
Sources. Primary: Energy Institute, Statistical Review of World
Energy 2026 , via Our World in Data. Final: IEA, Total Final Consumption by
Source . Device efficiencies: Cullen & Allwood (2010), Energy
35(5):2059–2069, table 3, which publishes the energy efficiency and the quality factor
separately — which is what lets the same chain be drawn under either ruler.
What is estimated. How each carrier's energy divides between its
devices is read off the volumes in their figure 2 (2005) and rescaled to our carrier
totals. Their efficiencies are 1990 device data rescaled by the authors to 2005; apart
from lighting, raised to 22 % for an LED-dominated stock, we have not updated them — so
this is closer to a portrait of the 2005 device stock than of today's. Coolers exceed
100 % energy efficiency (they move heat rather than make it) and are capped for drawing.
Projections. Years past the last observed one are our own
extrapolation on the IEA World Energy Outlook 2025 Stated Policies growth rates.
Robin Girard, MINES Paris — PSL. Content CC BY 4.0, code MIT.
Source
repository . v1.0