As Iowa’s population has grown, so, too, has the state’s demand for energy.
To measure how the number of Iowans has grown compared to how much power everyone is using, we took a look at U.S. Census Bureau population data and state energy consumption data logged annually by the U.S. Energy Information Administration.
By combining population statistics with overall energy use numbers, we can chart the state’s overall energy consumption per resident.
It should be noted that energy consumption covers all users, from residents to businesses and commercial or industrial users.
In 1960, Iowa had approximately 2.77 million residents. In the same year, the state consumed more than 602 trillion Btus of energy. That breaks down to more than 217 million Btus per Iowan.
A Btu, or British thermal unit, is a standard unit to measure how much energy it takes to produce heat. It is the amount of heat required to raise the temperature of 1 pound of water by 1 degree Fahrenheit.
To compare, Iowa’s population had grown to about 3.13 million people in 2016. Statewide energy consumption that year climbed to nearly 1.53 quadrillion Btus — or more than 488 million Btus per Iowan.
So while the state population grew by about 13 percent over those 56 years, energy consumption per resident more than doubled.
While Iowa’s energy consumption has increased over the years, the state’s energy production patterns have been shifting — primarily away from coal and toward wind turbines.
Using U.S. Energy Information Administration data from 1960 to 2016, we can see some trends in the state’s three largest energy sources — coal, natural gas and wind. The agency also measures other sources of energy, but for this chart, we will focus on the three sources that make up the biggest share of Iowa’s energy grid.
In 1960, natural gas led the three resources, with the state consuming about 194 trillion Btus, Coal provided 116 Btus. Wind was largely nonexistent as a significant energy source until the 1990s.
Coal and natural gas first swapped places in 1982, when the state began consuming more coal than natural gas. That trend would hold true until 2016 after years of declining coal use paired with growth in natural gas.
Coal, despite being the state’s top energy source for decades, has fallen nationwide, due in large part to the cost of natural gas coming down because the supply went up because of increased fracking. What’s more, many Iowa utilities are pursuing more renewable energy resources.
Speaking of renewables, Iowa’s wind industry has been growing exponentially. In 2016, wind had reached more than 185 trillion Btus and continues to grow.
Industry experts point to federal production tax credits as spurring much of the state’s initial wind investment. More than a third of Iowa’s energy comes from wind turbines.
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