Energy Density
The amount of energy stored per unit mass or volume of a fuel or energy source.
Formula
Energy Density = Energy Content ÷ Mass (or Volume)
Real World
Tesla's Model 3 battery pack stores around 0.9 MJ/kg — roughly 50 times less energy-dense than petrol at 45 MJ/kg — which is why electric vehicles require heavy battery packs and why range anxiety remains a barrier to mass adoption.
Exam Focus
Always state units (MJ/kg or MJ/L) and specify whether you mean gravimetric or volumetric density to gain full marks.
How well did you know this?