Before we can talk about the current state of the world in terms of energy, we need a common language to describe relative amounts of energy.
In this course, we primarily use two units of energy: the BTU and the quad.
BTU
A BTU1United States Energy Information Administration, 2009, Energy annual review 2008, 447 p., http://www.eia.gov/ (accessed May 1, 2014)., or British Thermal Unit, is defined as “the amount of energy needed to cool or heat one pound of water by one degree Fahrenheit.” It is also said that the power in the head of one match is approximately equal to one BTU.
How much is a BTU in calories?
If you’re into exercise, a BTU is equivalent to 252 calories.
The energy content of oil is quite dense. One teaspoon of crude oil contains about 180 BTU (or, when burned, the equivalent of over 45,000 calories), and a gallon contains about 140,000 BTU.2The Engineering Toolbox, 2015, Energy content in common energy sources, http://www.engineeringtoolbox.com/ (accessed June 29, 2015).
Quad
A “quad”3United States Energy Information Administrations, 2014, International, http://www.eia.gov/beta/international/ (accessed May 1, 2014), or a quadrillion BTUs, is equivalent to one quadrillion (1,000,000,000,000,000) matches.
The quad is the unit used by the U.S. Department of Energy when discussing global and national energy budgets.
How large is the global energy budget?
World total primary energy consumption for 2019 was 584 quads, an increase of 1.3% from the previous year. Total U.S. primary energy consumption in 2019 was equal to 95 quads and represents 16% share of world energy consumption.4BP Statistical Review of World Energy, 2020, all data 1965-2019. http://www.bp.com/statisticalreview/ (accessed: 8/4/2020).
Images: “Wooden Kitchen Match” by iStock