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  • Writer's pictureSarah Whiteford

Where do we get our energy?

We need energy. Heating, cooling, transportation, food, cat videos, all of it takes some form of energy to produce. So how much energy do we use, and where does it come from? It’s a complex answer, but we’ll break it down into simple pieces.

Image Credit: Inside Energy

How much energy do we use?

According to the U.S. Energy Information Agency, in 2015 people all over the world used about 575 quadrillion Btu of energy. This is a huge number – quadrillion (15 zeros!), is after trillion (12 zeros), which is after billion (9 zeros). Let’s try for millions: as it turns out, when that number is distributed across the average person per year, it comes out to 78 million Btu per person. That’s still 6 zeros, and a little hard to imagine. We can break it down further: since a match puts out about 1 Btu of energy, so if a person used match energy all year, all they would have to do is light 2.5 matches per second for the whole year! That’s the average, but the United States uses about 1/6 of the world’s energy, so Americans would have to light about 10 matches per second to keep up with their energy demands. Yikes.

Luckily, we don’t use matches to generate much of our power, so we use other sources. My great-great-great grandparents would have used wood (ha!) for their energy needs, as did most of the United States. Over time, petroleum products became the most common source of energy, and has held the top spot since 1950. People in the United States don’t use as much energy as you might expect from the above example, we actually rank 11th in per person energy usage, using 3 times more energy than China, but only 1/3 the energy that people from Iceland do (that’s about 30 matches a second for Icelanders). Funny enough, most of Iceland’s energy is generated by hydroelectric and geothermal power, so there isn’t a good method to store the energy being created. This means, the energy being generated is used or lost. They also produce a lot of the world’s aluminum, which takes significant energy, meaning they are essentially exporting energy as aluminum.

Image Credit: Inside Energy

So where does all this energy come from?

The largest source for energy is petroleum, which is used mostly for transportation. However, the biggest energy need is electricity, at about 40% of our energy needed. As Inside Energy says, “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.” Coal was the top producer of electricity until more recently, when fracking became more common and natural gas was more available. Electricity mixes change over time as people switch to more available and more renewable fuels.

According to the U.S. Energy Information Administration, our electricity generation is split like this:

  1. Fossil Fuels at 62.7%, this includes natural gas, coal, and petroleum.

    1. Natural gas: 38.4%

    2. Coal: 23.5%

    3. Petroleum and other gases: 0.8%

  2. Nuclear: 19.7%

  3. Renewables: 17.5%, including wind, hydropower, biomass, and solar.

  4. Other: 0.3%

The United States uses less coal and more natural gas, nuclear, and renewables than the average country. On the renewable end of the spectrum, we mentioned Iceland above, they are at almost 100% renewable energy usage, as is Norway. Most of that comes from hydropower, combined with geothermal and wind. The USA comes in at around 18% total renewable energy.

Image Credit: World Nuclear

How do these energy sources work?

Fossil fuel power plants burn coal, gas, and oil to create heat, then use hot gases or steam to spin turbines that generate power. The plants are inexpensive and reliable, but they generate higher levels of pollution such as CO2. Since the plants require a lot of fuel, changes in fuel prices due to demand, supply, or transportation can greatly affect the price of electricity.

Hydroelectric power is usually created by dams. They are low-carbon power production but require unique locations. Slowing river flow can also have negative effects on the surrounding area’s environment and population. Accidents are uncommon but can be catastrophic.

Nuclear power splits atoms, using the resulting heat to spin a turbine and produce electricity, similar to a fossil fuel plant’s steam electricity generation. The biggest difference is fission does not produce greenhouse gas or air pollution and is more environmentally friendly. Nuclear plants are also very reliable, and its fuel can be used for years in the reactor. The resulting nuclear waste can also be recycled into newer reactors to generate more power.

Wind and solar also produce low-carbon power, but with limited reliability. Changes in weather such as dust, clouds, or wind directly affect the amount of the energy produced, and with limited energy storage options, it usually cannot be used as a primary energy source. These solutions also require a lot of space for wind or solar farms.

Biomass plants are similar to coal and gas plants but use biomass like trees, wood, biogas, or other waste. It has similar problems to fossil fuel mentioned plants such as pollution, high costs of transportation, and in some cases, even higher emissions.

Image Credit: eletimes

What does all this mean for electricity?

Fossil fuels are still the primary electricity generator in many areas, but according to Solar Energy International, we are using them at 100,000 times the rate they are being created. The shift to cleaner electricity generation will continue from all sides. More efficient solar panels, better wind turbines, nuclear power plants that reuse waste, and better power storage solutions will ensure uninterrupted power as our global need continues to grow. If you’d like to see a short video of where our energy comes from and how our energy needs are changing over time, check out this one from Inside Energy:

Happy Fun Fact Friday!


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