Convert Horsepower-Hours to Terajoules
Convert Horsepower-Hours (hp·h) to Terajoules (TJ) instantly and accurately.
Conversion Formula
TJ = hp·h × 2.684519538e-6
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 Terajoules
A terajoule (TJ) is 10¹² J - the scale of nuclear yields in the kiloton range and large industrial accidents. One kiloton of TNT = 4.184 TJ; the Hiroshima bomb (15 kt) released ~62.8 TJ. The Halifax Explosion (1917) released ~3 TJ. A 500 MW coal plant consumes ~51.4 TJ/h of thermal input. Daily primary energy of Denmark is ~250-300 TJ; the UK ~3,800 TJ/day. A 1 GW nuclear reactor at 90% capacity factor generates ~77.7 TJ/day. 1 TJ = 10¹² J = 277,778 kWh = 277.78 MWh = 23.88 ktoe.
Quick Reference Table
| Horsepower-Hours (hp·h) | Terajoules (TJ) |
|---|---|
| 1 hp·h | 2.685 × 10-6 TJ |
| 2 hp·h | 5.369 × 10-6 TJ |
| 5 hp·h | 1.342 × 10-5 TJ |
| 10 hp·h | 2.685 × 10-5 TJ |
| 25 hp·h | 6.711 × 10-5 TJ |
| 50 hp·h | 0.000134226 TJ |
| 100 hp·h | 0.000268452 TJ |