Convert million barrels of oil equivalent to quad

Energy statistics reduce every fuel to a common yardstick. The tonne of oil equivalent is defined by the IEA as 41.868 GJ (11.63 MWh), roughly the energy in a tonne of crude; national energy balances are in Mtoe. The barrel of oil equivalent is used by oil companies, and its exact value varies between them, so figures are approximate. The tonne of coal equivalent is 29.3 GJ (7 million kcal), which Germany writes as SKE (Steinkohleeinheit). Natural gas is counted by volume or, as LNG, by mass: a billion cubic metres of gas is about 0.9 Mtoe.

The British thermal unit, the heat that warms a pound of water by one degree Fahrenheit (1,055 J), is now mostly an American unit. US gas bills are in therms of 100,000 Btu (29.3 kWh), wholesale gas is priced per million Btu (MMBtu), and national energy statistics are in quads, 10¹⁵ Btu: the US uses about 100 quads a year. The ton-hour is the cooling delivered by one refrigeration ton over an hour, 12,000 Btu.