Energy explained: Where does it come from and how much do we use?
Nothing in our world – cars, coffee, cat videos, even canned pineapple – would exist without energy. But although energy makes everything work, most of us don’t know the answers to even the most fundamental questions:
How much energy do we use?
And where does our energy come from?
These questions are simple, but the answers lay the foundation for more complex issues, from pipelines to land use to grid infrastructure. We’ve covered the basics in the video above. For a deeper look, let’s put on our data goggles.
How much energy do we use?
Worldwide, humans used about 575 quadrillion Btu of energy in 2015, according to estimates from the U.S. Energy Information Agency. With a global population of 7.3 billion, that works out to 78 million Btu per person, per year.
Having trouble intuiting how big that is? Us too. Here’s one way to wrap your head around it: A Btu is roughly the energy released in a single match. So if you wanted to consume all of your energy in the form of matches, you’d have to strike 2.5 every second. We don’t recommend trying it.
Americans are heavy energy users, accounting for roughly one-sixth of world energy consumption. That’s 303 million Btu a year per American. Using our match analogy, you’d need to light nearly 10 matches a second to keep up with the energy appetite of the average American human.
And how has the amount of energy we use changed over time? Americans today use roughly three times the amount of energy our great-grandparents used 100 years ago. And back then, they used more wood than oil.
Energy use skyrocketed in the 20th century, but has been declining in recent years.
The U.S. ranked 11th, worldwide, in terms of energy use per person, according to 2013 data from the World Bank. Per person, the average American uses three times as much energy as someone in China. But Americans only use a third of the energy, per person, as Icelanders. (Why does Iceland use so much energy? Short answer: Their main energy sources, hydroelectric and geothermal power, can’t easily be stored. So they must use it or lose it. Iceland has a huge aluminum industry, which is energy-intensive. So essentially, they export their abundant energy supply in the form of aluminum.)
Where does the energy we use come from?
The biggest single source of energy humans use, worldwide, is petroleum. That’s true in the U.S. as well, and has been since 1950. Petroleum is primarily used for transportation: We turn it into gasoline and diesel that fuels cars, trucks, boats and other equipment.
But transportation isn’t our top energy need – electricity is. Nearly 40 percent of the energy we use globally goes to making electricity. We generate electricity in all kinds of ways: burning fossil fuels like coal, natural gas or petroleum; splitting atoms in nuclear reactors; harnessing the power of rivers with dams; converting wind and sunlight directly into electricity with turbines and solar panels.
In the U.S., coal-fired power plants have been our top source of electricity for decades. But in the past few years, natural gas has been cheap due to the rise of the still-controversial process of hydraulic fracturing, or fracking. As a result, natural gas-fired power plants are poised to be our top electricity source.
How does the electricity mix vary from country to country? The World Bank publishes data on the percent of electricity generated from various fuel sources (as of 2013):
- Coal accounts for 41 percent of global electricity generation; 17 countries get more than half of their electricity from it, including Mongolia, Poland, China, India and Australia.
- Natural gas accounts for 22 percent of global electricity generation; 31 countries get more than half of their electricity from it, including Qatar, Belarus, Tunisia, Singapore, Bangladesh, Nigeria, Mexico and The Netherlands.
- Nuclear accounts for 11 percent of global electricity generation; four countries get more than half of their electricity from it, France, Slovak Republic, Belgium and Hungary.
- Hydro accounts for 16 percent of global electricity generation; 37 countries get more than half of their electricity from it, including Nepal, Norway, Ethiopia, Georgia, Brazil and Canada.
- Renewables, like wind, solar and geothermal, account for 5 percent of global electricity generation. As of 2013, no country got more than half of its electricity from non-hydro renewables, although Denmark was very close, at 46 percent.
Regardless of where you live, our energy sources and uses are changing in major ways. Our great-grandkids’ energy profile will likely be just as unrecognizable to us as our great-grandparents’.