Gravimetric energy density as a transport constraint

Assembled from 10 blocks · 2 evidence · 6 related

1. Story
2. The quantity that decides which vehicles can be battery-electric and which cannot. Kerosene carries roughly forty-three megajoules of chemical energy per kilogram, about twelve kilowatt-hours; a complete lithium-ion battery pack carries something in the region of a fifth of a kilowatt-hour per kilogram at the pack level. That is a gravimetric ratio of order fifty to one. Two corrections apply and neither closes the gap. In favour of the battery, an electric powertrain converts stored energy to shaft work two to three times more efficiently than a gas turbine or a piston engine, so the useful-energy ratio is nearer fifteen or twenty to one. Against the battery, an aircraft burning fuel gets lighter as it flies — a long-haul jet can leave with more than a third of its take-off mass as fuel and land far lighter — while a battery aircraft carries its discharged mass to the destination, which worsens the range equation rather than merely shifting it. The consequence is a clean split. Where mass is a small fraction of the problem — cars, buses, urban delivery, short rail — electrification is straightforward and is happening. Where mass is the problem — long-haul flight above all — it is not a question of cheaper batteries but of a physical margin that incremental improvement does not cross. Short-range regional electric aircraft sit exactly at the boundary and are being flown; intercontinental ones are not near it. Not a place.
3. Knowledge
4. Gravimetric energy density as a transport constraint
5. Connections
6. Lithium-ion battery storage
7. Aviation
8. Evidence
9. Supports the sectoral emission structure used throughout this pack, the treatment of industry process emissions as distinct from energy emissions, the assessment of technology cost declines in solar, wind and storage, and the identification of aviation, shipping and heavy industry as hard-to-abate. V55 verification basis: not retrieved in this session; no chapter, table or page number is cited because none could be confirmed, and every sectoral share attributed here is given as a range rather than a figure.
10. The standard series for volume-weighted average lithium-ion pack and cell prices, supporting the roughly order-of-magnitude decline across the 2010s and the figure of about 115 United States dollars per kilowatt-hour reported in the 2024 edition. V55 verification basis: about.bnef.com was refused by the network egress proxy in this session; the 2024 figure is stated from author knowledge and the 2025 and 2026 editions were not seen at all, so the figure must not be presented as current. This is a commercial survey rather than a public statistical source, and its methodology is proprietary.