A Cue From Kitty Hawk: What the Wright Brothers Teach Us About Decarbonizing Flight


By Adam Bratis, NREL Associate Laboratory Director, Bioenergy Science and Technology

Early Flight Was Fueled by the Scientific Process — A photo showing the first powered, controlled, and sustained flight over a beach near Kitty Hawk, North Carolina. Like Orville and Wilbur Wright with their legendary flyer, NREL is using science to put a new notch in the storied history of aviation: climate-friendly flight powered by low- and zero-net-carbon sustainable aviation fuel. Photo from Library of Congress, Prints & Photographs Division.

The seeds of modern aviation didn’t merely sprout from two brothers’ dream of flight. They broke into the sunlight through the rigor of the scientific process.

I’ve heard that the Wright brothers tested hundreds of wing designs during their efforts to build and demonstrate the first fully functional airplane. Many of those wooden wings never took off. But every experiment — whether airborne or not — taught the American inventors something valuable.

Orville and Wilbur Wright carried insights back to their lab, where they polished their understanding of the dynamics of lift. They gathered detailed data, revised their assumptions, and improved their designs. It was rigorous applied science that earned extraordinary results.

On December 17, 1903, on a wind-swept beach 4 miles from Kitty Hawk, North Carolina, the Wright brother’s legendary flyer took off.

I recount that moment at Kitty Hawk because I believe we stand at another pivot in the rich history of aviation. To avoid the worst effects of climate change, we must rapidly and permanently reduce greenhouse gas emissions (GHG) across our economy, including in aviation.

We must again redefine flight with the rigor of science. But the clock is ticking with every ton of carbon dioxide released into the atmosphere.

A New Notch in History: Climate-Friendly Sustainable Aviation Fuel

Here at the National Renewable Energy Laboratory (NREL), we take a cue from the Wright brothers. We are doubling down on science we think will innovate aviation: upgrading renewable resources into affordable, net-zero-carbon sustainable aviation fuel (SAF).

SAF is a biofuel with all the same properties of conventional jet fuel but with a far lower carbon footprint. Made from a variety of renewable or waste resources — think forestry waste, bioenergy crops, garbage, and more — SAF is seen as critical for helping airlines decarbonize their aircraft.

The draw is primarily the fuel’s low GHG footprint. U.S. airlines are investing heavily in expanding the availability of SAF because the bio-derived fuel can reduce GHG emissions dramatically compared to today’s jet fuel. And it can do so while offering the same properties needed to support safe, reliable flight.

Here’s an example right from our biofuel refining labs.

NREL scientists invented a process to make SAF compatible with existing jet engines and that has a carbon footprint as much as 165% lower than fossil jet fuel.

Made from cheap, widely available wet waste — like food waste, manure, and sewage — NREL’s SAF from wet waste could enable large GHG reductions purely by keeping waste from rotting and releasing methane in a landfill.

If blended with conventional jet fuel, such a bio-based fuel can enable net-zero-carbon flight.

From Wet Waste to Flight — Using carbon-rich volatile fatty acids (VFAs) made from wet waste, like sewage, manure, and food waste, NREL’s refining process builds fuel molecules that can be used in existing jet engines and have a net-negative carbon footprint.

Low-Carbon SAF Starts in the Lab

This is one example among many of how NREL is transforming energy with technologies that unlock the low-carbon potential of renewable resources.

Through strong partnerships with the U.S. Department of Energy, aviation companies, and biofuel refiners, NREL scientists offer basic and applied research to bring more SAF to the market sooner rather than later.

· SAF from wood waste and regenerative-agriculture biomass. In partnership with Alder Energy, NREL is developing a process to upgrade bio-oil into cycloparaffin SAF — a pathway that could add value to standing dead wood in fire-prone areas or agricultural crops that store carbon in the soil.

· Corn stover to cyclohexane-rich SAF. Combined with process and catalyst innovations at partner universities and labs, NREL’s deacetylation and mechanical refining process makes it possible to convert corn stover into cyclohexane-based SAF — a potential boon to U.S. corn farmers.

· SAF from 2,3-butanediol. NREL scientists and research partners are scaling a novel fermentation process to produce 2,3-butanediol from widely available biomass sugars, which can be converted into low-carbon SAF that meets fuel performance standards.

Obstacles Ahead on the Flight Path

Together, emerging SAF technologies like these can help airlines make measurable progress on their goals to cut GHG emissions in half by mid-century.

Truth be told, however, hitting aviation climate targets requires a whole-system approach to decarbonization. From the ground vehicles speeding around terminals to the 777s powering across the Pacific, NREL offers airlines a range of solutions for lowering emissions.

But obstacles are ahead on the flight path. Demand for aviation is growing, expected to double pre-pandemic levels by 2050. SAF production needs scaled to keep up. We need to do more with less.

Seen through the urgent lens of climate change, SAF is critical for lowering aviation GHG emissions in as little as a few years.

What do the Wright brothers have to teach us?

Grease the Pistons. Tighten the Sprocket Chains.

The Wright brothers remind us of the value of persistence and trust in the scientific method.

“I confess that in 1901, I said to my brother Orville that man would not fly for fifty years,” Wilbur Wright famously said when accepting a Gold Medal from the Aero Club of France in Paris.

His work was hard. Building and flying the first airplane was an immense undertaking.

But Wilbur and his brother doubled down on their work. They refined the arc of their aircraft’s wings, lubricated the pistons in its small gasoline engine, and tightened the sprocket chains pulling its propellers.

In 1903, two years after he expressed his doubt, Wilbur watched his brother Orville fly and land the first airplane. Can you imagine his satisfaction?

Here in the 21st century, NREL has the facilities, capabilities, and expertise to harness the power of the scientific method like never before.

We pool resources and expertise through partnerships with other national labs, companies, and universities. We use supercomputers to analyze refinery components and SAF processes in a matter of seconds. Our databases put terabytes of information at the fingertips of NREL’s analysts, who work to understand the most economical and sustainable pathways for making SAF. We bring more minds to the problem.

Developing the next generation of renewable jet fuels won’t be easy. Innovation never is.

But like the Wright brothers’ dream of flight, our mission to decarbonize aviation is powered by more than a vision of avoiding the worst effects of climate change. Fueled by NREL’s capabilities and expertise, we stand to revolutionize flight with low-carbon, high-performance SAF.

Don’t believe it’s possible? Take a look back at Kitty Hawk.



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