Americans used a lot of energy in 2015 - 97.7 quadrillion British thermal units (BTUs) of it to be specific, according to a recent report from the EIA.  For reference, one quadrillion BTUs is equivalent to 45 million tons of coal, 1 trillion cubic feet of gas, or 170 million barrels of crude oil.”

It wasn’t always this way. Energy consumption was relatively low from the late 1700s through the 1800s, before booming during the 1900s. It’s all illustrated in the chart below:

The very first type of energy we used was biomass, which is a type of clean energy, where we use dead plant substances to produce energy. It is not that effective in producing large amounts of energy, which helps explain why it’s relative energy market share has fallen over the past few centuries.

However, it was the sole source of energy until the mid 1800s, which is when coal started to gain popularity. Coal dominated for nearly a century, before both natural gas and petroleum surpassed it, though oil’s usage was clearly much higher than both coal and gas. It’s also interesting to see that coal usage actually did not hit its high point until the 2000s, before it started decreasing again.

In the future, the EIA sees coal usage continuing its decline, while petroleum and nuclear usage flatlines. Natural gas and renewable energy are both growing rapidly, with the former expected to be the top source of American energy use by 2040.

However, who is actually using this energy, and exactly what percent of total energy use is each of these power sources? This is the primary question that a separate EIA report seeks to answer, as can be seen from the chart below:

The first thing that’s immediately apparent is how much more energy American business use than the American consumer. Resident and commercial use takes up a relatively puny 11% of the total energy share, with most of their use taking the form of natural gas. Among the business sectors, transportation is a big energy consumer, and they almost exclusively rely on petroleum.  This is largely because the transportation sector needs an energy source that’s easy to move around.

It is also easy to see that America has not weaned off its dependence on fossil fuels, with petroleum, natural gas and coal taking up a combined 81% of total energy use. Petroleum and coal have clear end users (transportation and electrical power respectively) but natural gas contributes significantly to every type of energy consumer, besides transportation. Nuclear energy has even less flexibility, with a full 100% of it being used to produce electricity.