Convert Horsepower-Hours to Exajoules
Convert Horsepower-Hours (hp·h) to Exajoules (EJ) instantly and accurately.
Conversion Formula
EJ = hp·h × 2.684519538e-12
About Horsepower-Hours
A horsepower-hour (hp·h) is the energy from one mechanical horsepower (745.6999 W) for one hour - exactly 2,684,519.54 J ≈ 2.685 MJ. James Watt coined the horsepower to compare his steam engines with mine horses; billing in hp·h preceded the kilowatt-hour tariff. The metric horsepower (PS = 75 kgf·m/s = 735.499 W) gives a slightly smaller metric-hp·h = 2,647,795 J, used in European and Japanese engine datasheets. Today the hp·h appears in marine engineering logs, mining energy accounting, and vintage industrial equipment. 1 hp·h = 2.6845 MJ = 0.74570 kWh = 641.19 kcal.
About Exajoules
An exajoule (EJ) is 10¹⁸ J - the scale of global energy consumption. World primary energy supply in 2022 was ~580-610 EJ: coal ~160 EJ; oil ~190 EJ; gas ~145 EJ; nuclear ~26 EJ; wind ~8 EJ; solar PV ~8 EJ. Global electricity generation of ~29,000 TWh = 104 EJ. Solar energy incident on Earth's atmosphere is ~5.5 × 10⁶ EJ/year - approximately 9,000× total human demand. Annual fossil fuel combustion releases ~490 EJ/year, producing ~36.8 Gt CO₂. 1 EJ = 10¹⁸ J = 277.78 TWh = 238.85 Mtoe.
Quick Reference Table
| Horsepower-Hours (hp·h) | Exajoules (EJ) |
|---|---|
| 1 hp·h | 2.685 × 10-12 EJ |
| 2 hp·h | 5.369 × 10-12 EJ |
| 5 hp·h | 1.342 × 10-11 EJ |
| 10 hp·h | 2.685 × 10-11 EJ |
| 25 hp·h | 6.711 × 10-11 EJ |
| 50 hp·h | 1.342 × 10-10 EJ |
| 100 hp·h | 2.685 × 10-10 EJ |