A quad is a unit of energy equal to 10¹⁵ (a short-scale

Long and short scales

The long and short scales are two of several different large-number naming systems used throughout the world for integer powers of ten. Many countries, including most in continental Europe, use the long scale whereas most English-speaking countries use the short scale...

 quadrillion

Quadrillion

Quadrillion may mean either of the two numbers :* 1,000,000,000,000,000 – for all short scale countries; increasingly common meaning in English language usage* 1,000,000,000,000,000,000,000,000 – for all...

) BTU, or 1.055 × 10¹⁸ joule

Joule

The joule ; symbol J) is a derived unit of energy or work in the International System of Units. It is equal to the energy expended in applying a force of one newton through a distance of one metre , or in passing an electric current of one ampere through a resistance of one ohm for one second...

s (1.055 exajoules or EJ) in SI

Si

Si, si, or SI may refer to :- Measurement, mathematics and science :* International System of Units , the modern international standard version of the metric system...

 units.

The unit is used by the U.S. Department of Energy in discussing world and national energy budgets. The global primary energy production in 2004 was 446 quad, equivalent to 471 EJ.

Some common types of an energy carrier

Energy carrier

According to ISO 13600, an energy carrier is either a substance or a phenomenon that can be used to produce mechanical work or heat or to operate chemical or physical processes....

 approximately equal 1 quad are:

• 8,007,000,000 Gallons (US) of gasoline
• 293,083,000,000 Kilowatt-hours (kWh)
• 36,000,000 Tonnes of coal
• 970,434,000,000 Cubic feet of natural gas
• 5,996,000,000 UK gallons of diesel oil
• 25,200,000 Tonnes of oil
• 252,000,000 tonnes of TNT or five times the energy of the Tsar Bomba
  Tsar Bomba
  Tsar Bomba is the nickname for the AN602 hydrogen bomb, the most powerful nuclear weapon ever detonated. It was also referred to as Kuz'kina Mat , in this usage meaning "something that has not been seen before"....
  
  nuclear test.