Quad
One quadrillion BTU (about 1.055×10¹⁸ J). Used to quote national and global energy use; US consumption was about 100 quads in 2005.
1 quad = 1.055055853×10¹⁸ joules (approximately).
About the quad
Energy planners reach for the quad when joules or gallons become unwieldy. One quad is a quadrillion (10 to the 15th power) British thermal units, a figure the US Department of Energy uses for national and world energy budgets. In SI terms it is about 1.055 exajoules, or 1.055 times 10 to the 18th joules.
Which BTU applies changes the last digits. The figure used here, 1.05505585 times 10 to the 18th joules, corresponds to the International Table BTU of roughly 1,055.06 J. The 59 degree Fahrenheit BTU used in American gas pricing would give a value about 0.02 percent smaller, and the Wikipedia article on the quad does not say which BTU it assumes.
For scale, one quad equals about 8 billion US gallons of gasoline or roughly 293 terawatt-hours of electricity. Wikipedia reports world primary energy production of about 638 quads in 2022. In 2005 the US economy used close to 100 quads, so the unit suits country-sized totals rather than anything a household buys.
Sources: Wikipedia: Quad (unit); EIA: British thermal units (Btu); Wikipedia: British thermal unit
Quad conversion chart
1 quad expressed in every other energy unit:
| Unit | 1 quad |
|---|---|
| Joules | 1.055055853×10¹⁸ |
| Kilojoules | 1.055055853×10¹⁵ |
| Watt-hours | 293,071,070,172,222 |
| Kilowatt-hours | 293,071,070,172 |
| British Thermal Units | 1×10¹⁵ |
| Calories | 2.521644007×10¹⁷ |
| Kilocalories | 252,164,400,721,797 |
| Megajoules | 1,055,055,852,620 |
| Gigajoules | 1,055,055,853 |
| Megawatt-hours | 293,071,070.2 |
| Foot-pounds | 7.781692623×10¹⁷ |
| Millijoules | 1.055055853×10²¹ |
| Electronvolts | 6.585140678×10³⁶ |
| Kiloelectronvolts | 6.585140678×10³³ |
| Megaelectronvolts | 6.585140678×10³⁰ |
| Gigaelectronvolts | 6.585140678×10²⁷ |
| Tons Of TNT | 252,164,400.7 |
| Tonnes Of Oil Equivalent | 25,199,576.11 |
| Therms | 10,002,387,672 |
| Ergs | 1.055055853×10²⁵ |
| Calories (IT) | 2.519957611×10¹⁷ |
| Kilogram-force Meters | 1.075857559×10¹⁷ |
| Horsepower-hours | 393,014,778,922 |
| Liter-atmospheres | 1.041259169×10¹⁶ |
More US customary units
- therm (energy)
- short ton (weight & mass)
- hundredweight (US) (weight & mass)
- slug (weight & mass)
- US gallon (volume)
- US quart (volume)
- US pint (volume)
- US cup (volume)
- US fluid ounce (volume)
- US tablespoon (volume)
- US teaspoon (volume)
- US gill (volume)
- US fluid dram (volume)
- US minim (volume)
- US legal cup (volume)
- US bushel (volume)
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