Before we get too deep into our discussion about CCUS, let’s talk about energy in general. Energy is the ability to do work and is derived from the utilization of physical or chemical resources, especially to provide light and heat or to work machines. In some cases the ultimate goal is to provide motion, for example, a car. Or, energy may be used to excite atoms and molecules on the microscopic level, for example to create heat in our homes.
Energy is critically important because our modern world operates in large part from the ability of humans to harness, deliver and expend energy. In short, we are serious energy consumers. At the same time that our energy needs are increasing, traditional sources of energy are becoming more difficult to find and extract. In the U.S., the development of unconventional methods for extracting natural gas, and the increased role of renewable resources, such as wind and solar, are changing the way we generate and use energy.
Let’s take a look at energy consumption globally, within the U.S., and regionally within the state of Texas. 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 related units of energy: the BTU and the quad.
BTU
A BTU, or British Thermal Unit, is defined as “the amount of energy needed to cool or heat one pound of water by one degree Fahrenheit.” Let’s look at a couple of intuitive examples to get a feel for the BTU.1British Thermal Unit. (2021, June 7). In Wikipedia. https://en.wikipedia.org/wiki/British_thermal_unit
The energy in the head of one match is approximately equal to one BTU.
A BTU is equivalent to 252 calories.
Quad
A “quad”, or a quadrillion BTUs, is equivalent to one quadrillion (1,000,000,000,000,000) matches.2Quad (unit). (2021, April 30). In Wikipedia. https://en.wikipedia.org/wiki/Quad_(unit)
Of note, the quad is the unit used by the U.S. Department of Energy when discussing global and national energy budgets.
Energy Density Described Using BTUs
If you want to use energy to move, it can be helpful to have a fuel that is dense. For example, The energy content of oil is quite dense. One pound of crude oil contains about 18,000 BTUs. In contrast, many forms of energy used in underdeveloped regions are not so dense: one pound of peat contains about 6,200 BTUs, and one pound of dung contains about 6,800 BTUs. Because oil is dense, when used as a fuel for transportation, it provides the benefit of allowing travel for long distances.3Engineering ToolBox. (2009). Energy Content in Biomasses used as Fuel. https://www.engineeringtoolbox.com/biofuel-energy-content-d_1356.html
