Lab Notes: A Journey Into the Future of Sustainable Aviation

In this episode of Transforming Energy’s Lab Notes series, hosts Kerrin Jeromin and Taylor Mankle are flying high into NREL’s research on sustainable aviation. The federal government and the aviation industry have lofty goals for decarbonizing aviation by 2050, but how can we get there? NREL researcher Scott Cary shares how national labs, like NREL, are key to identifying pathways to a more sustainable aviation sector.

Additionally, Dave Ulane, director of the Colorado Division of Aeronautics, and Erin Cooke, sustainability and resilience director at San Francisco International Airport, provide industry expertise on how partnerships, new perspectives, and new technology are helping realize bold renewable energy goals. 

This episode was hosted by Kerrin Jeromin and Taylor Mankle, written and produced by Allison Montroy and Kaitlyn Stottler, and edited by James Wilcox, Joe DelNero, and Brittany Falch. Graphics are by Brittnee Gayet. Our title music is written and performed by Ted Vaca and episode music by Chuck Kurnik, Jim Riley, and Mark Sanseverino of Drift BC. Transforming Energy: The NREL Podcast is created by the U.S. Department of Energy’s National Renewable Energy Laboratory in Golden, Colorado. We express our gratitude and acknowledge that the land we are on is the traditional and ancestral homelands of the Arapaho, Cheyenne, and Ute peoples. Email us at podcast@nrel.gov. Follow NREL on X, Instagram, LinkedIn, YouTube, Threads, and Facebook.

Transcript

[music]

Kerrin: Welcome to Transforming Energy: The NREL Podcast, brought to you by the U.S. Department of Energy’s National Renewable Energy Laboratory. I’m Kerrin Jeromin. 

Taylor: And I’m Taylor Mankle.  

Kerrin: Today, listeners, we want to tell you a story about aviation—specifically on these energy technologies that, in our own lifetimes really, could transform the sustainability trajectory of the industry. But to do that story justice, we have to take you back a bit—back a couple of generations to 1914 in Florida and a young pilot named Antony Jannus

[old timey music]

Taylor: Jannus is not a household name in aviation history. He wasn’t a colleague of the Wright Brothers. He wasn’t the first to fly across the Atlantic. He was just a good pilot. Which could be why he was tapped to fly the world’s first commercial airline flight on January 1 of 1914.

Kerrin: He piloted a Benoist Type 14 airboat from St. Petersburg, Florida, to Tampa. It was just a few miles across the bay, which is good because this particular type of plane only had a 125-mile range. It was just himself and one passenger—putting the plane at maximum capacity—and the ticket cost 10 dollars for a round trip. The price was subsidized by the city of St. Petersburg.

Taylor: Jannus’ flight was a success, and it went on to become part of the first regularly scheduled commercial airline routes in the United States—actually in the world. It was part of a newly minted airline: St. Petersburg Tampa Airboat Line. That company transported about 1,200 paying customers over the next 3 months—back and forth over Tampa Bay. 

Kerrin: Unfortunately, business also only lasted for those three months. The city subsidies ended, and the airline couldn’t maintain a profit.

Taylor: But of course, we all know that wasn’t the end for commercial aviation. Aircraft technology got a lot better over the next couple decades. That helped the business case improve. And it all happened really fast. 

Kerrin: Shall we share a few highlights? 

Taylor: Absolutely. 

[plane sounds]

Kerrin: In 1927, Charles Lindbergh, an American, famously flew solo across the Atlantic, non-stop. In 1935, the Douglas DC-3 propeller aircraft flew for the first time. The Smithsonian notes that the DC-3 was the first airliner to fly profitably without government subsidy. 

Taylor: Just 17 years later—in 1952—jets superseded propeller airplanes. They were more efficient, flew farther, and they carried even more passengers. 

Kerrin: By 1976—we had supersonic—faster than the speed of sound—flight. 

Taylor: And of course, we know that today—2024—there are 100,000 flights globally per day via jets that are 50% more efficient than those in the 60s. 

Kerrin: All of that progress in just 110 years—from Jannus’ airboat flight with only one passenger to today’s global, highly efficient, meticulously regulated aviation network. It makes you wonder  about the next 100 years—what technological feats might lie ahead for this storied industry? What moment might mark the next great gust of innovation?

Taylor: Time will only tell, but my mind goes to another flight—this one on Nov. 8, 2023, less than a year ago, between London and New York.

[audio]

Kerrin: This flight was a transatlantic flight using 100% sustainable aviation fuel, which most people call SAF for short. Now, we’ve mentioned it on several episodes, but if you haven’t yet heard of SAF, it is this fairly new renewable jet fuel. It has the same properties as the petroleum jet fuel used in probably 99% of flights today. 

Taylor: But SAF has a far smaller net carbon footprint. I say “net,” because burning SAF in a jet engine does release carbon dioxide—it is a hydrocarbon fuel.

Kerrin: But the process of growing the renewable resources used to make SAF—things like corn stover, logging waste, algae, and perennial grasses—and then turning those resources into a liquid fuel, pulls a lot of that carbon dioxide back out of the atmosphere. Sometimes it can remove even more than was put there in the first place. 

Taylor: For the aviation industry, it was a very big deal that a jet could fly across the Atlantic using only SAF. It showed that commercial flight is technically achievable without further contributing to climate change. 

Scott Cary: This very complex engine system, an aircraft system that's been finely tuned, to be safe, has been able to adapt to a different product. And that's taking, you know, decades of work to be successful. In terms of being able to transition off of a finite amount of resources we have and petroleum to something that's reusable is pretty significant.

Kerrin: That was Scott Cary, who is a research engineer here at NREL. He is a leading expert on the energy complexities of airports, airplanes, and especially new technologies, like SAF, that can help aviation meet sustainability goals. 

Scott Cary: It's not just about the biofuel, it's about the efficiency and it's about moving things forward to reduce cost while you're also reducing emissions and noise.
All those are, you know, help the aviation industry be a better neighbor, while also improving their ability to provide service at a fair cost.

Taylor: Cary spends a lot of time working and talking with airlines and industry, and with state and federal agencies. He works on research and development  projects with experts at the U.S. Department of Energy, NASA, and the Federal Aviation Administration. And his goal—or NREL’s goal really—is to understand how our lab can help those agencies and aviation stakeholders realize their renewable energy goals.

Scott Cary: You know the national labs system is there to be somewhat the impartial third party to help industry accelerate adoption of new technologies. If it was not NREL, it was individual companies, in some cases, some of that that precompetitive research that’s needed would never get to the point where it could be actually deployed in industry. Because it's either too costly or each individual company doesn't have enough resources to do it by themselves. So, the national lab becomes that place to say, let’s move these things forward where these individual companies could say, yes, it’s viable, it’s safe, and we’re ready to move.

Kerrin: Getting new aviation technologies ready for companies to adopt and start using widely is critical to the industry and federal government—because, well, they need them. Take SAF, for example, The U.S. government has a goal of producing 3 billion gallons of SAF by 2030. By midcentury—2050—they want the country to make enough SAF to cover 100% of jet fuel demand. 

Taylor: To put that into perspective, the U.S. consumed about .023 billion gallons of SAF all of last year. That’s 130 times less than where the government wants to be in about six years, according to a 2024 NREL report.

Kerrin: And that’s just the federal government’s goal. The aviation industry itself has its own net-zero goals, and these goals include decarbonizing the entire aviation ecosystem.  

Taylor: In particular, they are targeting the emissions associated with airport buildings and energy systems; the deployment of electric or potentially hydrogen trucks, buses, and baggage tugs; leveraging SAF for both short- and long-haul flights; and the energy infrastructure to support it all. 

Kerrin: And this shift is happening at the same time that experts are also saying commercial aviation demand may double by 2050—that is double the passengers in 25 years. 

Taylor: If the grand technical challenge back in 1914 was to make any flight profitable, today we might say it is figuring out how to completely overhaul the aviation energy system in just a handful of years. 

Kerrin: It’s a tall order—which is why so many airlines, tech developers, and agencies are increasingly interested in the research happening here at NREL—people like Dave Ulane, the director of the Colorado Division of Aeronautics.

Dave Ulane: You know, I gotta tell you, being a part of the next evolution of aviation and aviation technology is so exciting and knowing what all of that technology is going to do to help Coloradans move around better, more efficiently, safer is just going to be amazing. 

Taylor: Ulane’s state agency—part of the state department of transportation—is working with NREL to scope out the energy and financial implications of deploying sustainable aviation technologies in Colorado. 

Kerrin: NREL’s 18-month study is broad and ongoing, but Colorado wants to see how new technologies can make aviation in the state more accessible, efficient, and sustainable. Basically: Can the state use new sustainable technologies to lower emissions and improve quality of life?

Taylor: To answer that question, NREL is analyzing how Coloradans move throughout the state and how this demand might align with the capacity of the state’s 76 airports, spread across mountains, deserts, and plains. 

Kerrin: NREL is studying how to optimize routes from those airports to make flight faster and more accessible. It is predicting infrastructure needs—future fuel and power requirements to support a new generation of aircraft that run on clean electricity, hydrogen, and/or sustainable aviation fuel.

Taylor: The ultimate goal, really, is to help Ulane’s agency know what is needed to unlock the benefits of new aviation technologies. 

Dave Ulane:  think the biggest challenge is getting all the Tetris blocks to align at the same time between the aircraft technology, the ground infrastructure, the policy, the funding, having all of that come together so that nothing is beating something else and wanting for something else is going to be really important.

Kerrin: Tetris blocks is a fitting analogy for this sustainable aviation energy transition. 

Taylor: Right? Every block is a little different. It would be easy to fit them together if they weren’t descending faster and faster—increasing the pressure as they fall. For sustainable aviation, a lot of the technologies needed to reach net-zero greenhouse gas emissions have been developed or are well-underway.

Kerrin: SAF is already used on the west coast, as well as some airports in a couple of Colorado mountain towns. Startup companies have demonstrated and are seeking federal approval for electric and hydrogen aircraft, so we could start seeing them in commercial use this decade. 

Taylor: But back to the Tetris blocks—the great challenge for deploying these technologies is fitting them together neatly and affordably into the 120-year-old aviation system we already have—and fast. 

Kerrin: That kind of complicated energy challenge is fortunately NREL’s niche. The lab has a long history of these impactful studies to help partners jump really big hurdles.

Taylor: Very true. 

Kerrin: For example, remember those electric airplanes I mentioned? A 2021 NREL study showed that small electric airplanes could potentially be cheaper to operate for some of today’s regional flights. These aircraft also have the advantage of being super quiet, and they don’t produce emissions. 

Taylor: To be clear, we are talking 6 to 9 seater planes for flights under 400 miles—say a flight in Colorado between Grand Junction and Denver.

Kerrin: Right. But many folks question what it’s going to take to charge their giant batteries. Can airports actually supply that kind of energy? I mean, what kind of infrastructure upgrades would they need? How much responsibility falls to the local utility and how much would that cost? 

Taylor: In partnership with NASA—perhaps the biggest player in aviation technology innovation—NREL is actively looking into those questions. The laboratory is part of a project called Airports as Energy Nodes—AENodes for short. Here’s Scott Cary again.

Scott Cary: With AEnodes, what we are doing is we're looking at the small commercial airports, but the end destinations you get on with the small commuter aircraft and then also the general aviation locations to say what would an electrified or potentially hydrogen future look like for aircraft going into those small airports and what assets may already be on the airport or could be added to the airport to help meet the energy demands of those new aircraft and how could that potentially be an asset for those local communities.

[Pause]

Kerrin: Maybe you noticed a throughline in these two NREL projects—the one with the state of Colorado and the other with NASA. They aren’t just about helping deploy sustainable aviation technologies to lower greenhouse emissions. 

Taylor: Right. They also center around benefits to communities. They center around partnerships. These technologies could make it easier and cleaner for Coloradans to move about. Or they could make local airports the energy hubs that can not only charge aircraft but also provide backup power to communities in crises, like after a natural disaster. 

Kerrin: Sustainable aviation technologies have a lot of potential to make both small towns and big cities more resilient. Achieving those potential benefits, though, takes an extensive community of stakeholders.

Taylor: Erin Cooke, who is the sustainability and resilience director at San Francisco International Airport, agrees that partnerships are crucial to disrupting the industry. NREL caught up with her at a recent conference.

Erin Cooke: Partnership is essential. We can't do it alone. One airport can't solve the sustainable aviation challenges that really need to be addressed by our industry, and it can't just be one aspect of our industry or one component of our sector, in that. It's a multi-billion if not trillion dollar question and we need everyone to contribute, everyone to show up, and everyone to solution solve together.

Kerrin: Sure, new technologies can make aviation more efficient, equitable, and sustainable, but the real impact comes with putting the pieces together in a way that supports everyone.

[music]

Taylor: Remember Jannus? The airboat pilot in 1914? We started this story with him because we see so many historical parallels between then and now. In that moment, even as Jannus landed that first commercial flight, there was so much excitement and possibility around the future of flight. I mean, for the first time, people were able to travel by air. But that possibility came with uncertainty and so many unanswered questions. How to make it profitable? How to make airplanes safer, more reliable?

[old timey music]

Kerrin: And still, I get the sense the small aviation community in 1914 had at least an inkling on how airplanes would go on to transform life in the United States. They were optimistic. They had this sense that the industry was going somewhere. IN fact, Jannus’ employer, a guy name Percival Elliott Fansler, made a speech to a huddle of spectators on the tarmac—right before takeoff. He said, “What was impossible yesterday is an accomplishment today, while tomorrow heralds the unbelievable.”  

Taylor: And here we are at our own moment of uncertainty, but also hope and enthusiasm for a more sustainable future. For the first time, humanity can travel by air without unmitigated carbon emissions that drive climate change. We just need to figure out how to leverage that.

Scott Cary: What do future fuels look like because we’re not tied anymore to kerosene as our base fuel? We now have the opportunity to say now, what if, what if we don’t have to make every fuel look like kerosene? What is the next fuel? Fuel, whatever we wanna call it, whether it’s an electron or a molecule or a liquid. What is that next fuel gonna look like?

Kerrin: Along the lines of Scott Cary’s questions, what is sustainable aviation going to look like? There are still technical and economical questions that researchers are actively looking into, just like they were back in 1914. But if aviation history provides us any clues—and that is a big if—the rate of technological progress could be unbelievable.

Taylor: If aviation history was a book flipped forward starting in 1914, you’d see Jannus and his airboat; you’d catch glimpses of profitable commercial airlines; you’d see jets taking off for the first time; maybe quick photos of countless engineers and scientists who devoted their careers developing them.

Kerrin: Beyond 2024, the page is blank. But today’s ongoing aviation research gives us a sense of what is to come—draft sketches of new technologies and milestones. More demonstration flights; biorefineries spread across the country that turn abundant renewable carbon resources into low-carbon SAF; battery-powered airplanes so quiet they are barely audible; highly efficient, electrified airports that generate their own clean power; better connected communities; a decarbonized aviation system. 

Taylor: And if you look even closer, behind many of those technical schematics, in those pages, you might even find the fingerprints of NREL researchers, too. 

[interstitial music] 

Kerrin: Thanks for joining us on this sustainable aviation journey today on Transforming Energy: The NREL Podcast. As always let us know what other topics you’d like to hear more about! You can email us at podcast@nrel.gov and rate us five stars on your favorite podcast platform.  

Taylor: We’ll be back with more news from NREL soon!

[music, fades]  

This episode was written by Erik F. Ringle. Our theme music is written and performed Chuck Kurnik, Jim Riley, and Mark Sanseverino, of Drift B-C and episode music by Ted Vaca. This podcast is produced by NREL’s Communications Office and recorded at the National Renewable Energy Laboratory in Colorado. We express our gratitude and acknowledge that the land we are on is the traditional and ancestral homelands of the Arapaho, Cheyenne, and Ute peoples. We recognize and pay respect to the Indigenous peoples from our past, present, and future, and are grateful to those who have been and continue to be stewards of this land.