The United States runs on roughly — quadrillion BTU per
year — extracted, refined, burned, transformed, and finally either delivered as useful
work or radiated away as waste heat. The single biggest insight in this chart isn't on
the left or right but in the difference: — quads never reach
a useful endpoint. Internal combustion engines lose ~75%, thermal power plants ~65%, the
rest in transmission, friction, and end-use inefficiency. The path to electrification is
a path to halving total primary-energy demand without losing any actual service.
PetroleumNatural gasCoalNuclearBiomassWindSolarHydroflow width ∝ quads/year · all flows colored by source
Total primary energy
—
quads/year · all sources
Useful energy delivered
—
—% of primary energy
Rejected energy (waste heat)
—
—% of primary energy
Fossil share
—
petroleum + gas + coal
SOURCE · Lawrence Livermore National Laboratory's annual U.S. Energy Flow Chart
(flowcharts.llnl.gov),
with values cross-referenced against EIA Monthly Energy Review (MER). A quad
is 1015 BTU = 1.055 EJ ≈ 293 TWh — the standard unit for total U.S.
energy accounting. Rejected energy is what gets emitted as low-grade heat
rather than doing useful work: tailpipe exhaust, cooling-tower plumes, transmission
losses, A/C compressor heat. Useful energy is what actually moves a vehicle,
heats a building, runs a motor, or lights a room — the demand we'd still need to
satisfy if every joule were converted perfectly. The most counterintuitive line on the
chart: transportation rejects ~75% of its primary energy input, almost entirely
to ICE thermodynamic losses. Electrification doesn't reduce useful energy — it
collapses rejected energy. A full EV fleet would shrink the transportation sector
from ~28 quads to ~9 quads of primary input for the same service.
Updated annually; the most recent LLNL chart is the 2023 release (Oct 2024).