A GOP Senate candidate’s muddled claim about windmills and greenhouse gas emissions

Eli Bremer is one of seven Colorado Republicans vying to be the party’s nominee to face Democratic Sen. Michael Bennet in the midterm elections. Bremer, a former  pentathlon Olympian, criticized Democrats’ emphasis on renewable energy, saying that it isn’t as green as Democrats make it out to be.

"If you look at windmills, there’s a lot of greenhouse gas emission cost that we gloss over," Bremer said in a Fox News interview March 23. "We extract the raw materials from the ground, process them, assemble them, maintain them for the lifespan of the windmill, then we decommission them. Virtually every expert that I’ve talked to believes that the overall return is negative."

Is it true that in terms of greenhouse gas emissions, the lifetime return on wind turbines is negative? We reached out to Bremer’s campaign to see what experts he relied on, and we didn’t hear back.

But what he said runs counter to every major study of this issue. 

While Bremer was singling out windmills, the fact is that no matter what the fuel — natural gas, wind, solar, coal, etc. — you have to build whatever it is you’re going to use to generate electricity. 

"Industrial infrastructure requires energy inputs and in that way, windmills or power plants, or for that matter, football stadiums, are the same," said Carey King, assistant director at the University of Texas at Austin Energy Institute.

The energy used in construction emits greenhouse gases. Once you’ve emitted those greenhouse gases, you can’t undo them. But that doesn’t mean all sources of electricity are equal.

The key question, King said, is how does wind compare to other ways of making power?

Unlike a plant powered by natural gas or coal, where you have to burn fuel and release more greenhouse gases every day to make electricity, a wind turbine requires a tiny amount of energy once it’s up. The longer it stays in service, the lower its lifetime carbon footprint per kilowatt hour, because the initial greenhouse gas emissions tied to construction (and end-of-life decommissioning) get spread out over more years and electrical output.

There are two ways to look at the emissions of windmills, and we’ll consider both. There’s the energy payback time and lifetime carbon footprint.

For decades, researchers have been assessing how long a windmill must generate power before it creates more energy than it took to build it. This work folds in all the steps that go into turning wind into electricity. Study after study has found that when all is said and done, a properly placed turbine nets out positive fairly quickly.

A 2016 study from Danish engineers looked at onshore and offshore turbines and found that the "energy payback time" for all technologies was less than one year.

A group of engineers in Texas did similar work and reported in 2016 that "the payback times for CO2 and energy consumption range from 6 to 14 and 6 to 17 months," with on-shore facilities having a shorter payback.

The longest payback period we found came from a 2019 study from engineers at the University of Texas at Arlington who factored in the wind speeds from a working wind farm in Texas with 200 turbines. By their calculations, a turbine at that wind farm that lasts 20 years will reach a full energy payback in less than six years.

They examined in detail the energy it took to move the turbine components from where they were made in Spain to the Lone Star Wind Farm near Abilene, Texas. They also measured the energy it took to get raw materials to the factories in Spain where manufacturing took place. The wind at the Lone Star Wind Farm varies and the researchers used that data to find the actual average wind speed through the year. 

Across all studies that compare the energy that goes into the wind power system to the energy it produces, whether it takes one year or six, a wind turbine lands in positive territory.

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There’s not an exact mapping of energy inputs to greenhouse gas emissions. But "a faster energy payback period should translate into a lower carbon emissions per kilowatt hour," said King with the Energy Institute.

Another way to compare different sources of electricity is to look at how much carbon dioxide, and its equivalents, it takes to produce a certain amount of power — often measured in kilowatt hours.

In 2021, natural gas and coal produced about two-thirds of America’s electricity. Wind accounted for about 9%, hydropower for about 6% and solar about 3%.

In 2021, a team at the National Renewable Energy Laboratory reviewed the findings from about 350 studies of the carbon footprints of all major energy sources. The higher the grams of carbon dioxide equivalents per kilowatt hour, the greater the carbon footprint. 

Here’s what they found in terms of median grams of CO2 equivalents per kilowatt hour: 

• Wind: 13 

• Nuclear: 13

• Hydropower: 21

• Solar: 43

• Natural gas: 486

• Coal: 1,001

The high numbers for fossil fuels stem from the ongoing need to burn fuel to make power. A windmill emits about one fourtieth as much greenhouse gases as a natural gas-fired power plant.

Bremer said once you factor in the emissions that come from building and putting up a windmill, you end up with a net negative.

This is not correct, based on the most comprehensive assessments that compare the carbon footprint of all sources of electricity across their lifetimes.

Wind power comes out far ahead of fossil fuels like natural gas and coal, because it doesn’t require the constant release of greenhouse gases to produce electricity. 

It takes between one to six years for a wind turbine to produce more power than is used to build, install, maintain and retire it. In terms of carbon footprint, a wind turbine produces about 40 times less greenhouse gases than a natural gas-fired plant.

We rate this claim False.