Kerrin: Welcome to Transforming Energy: The NREL Podcast, brought to you by the U.S. Department of Energy’s National Renewable Energy Laboratory. We’re highlighting the latest in clean energy research and innovations happening at the lab. It’s Wednesday, May 29. I’m Kerrin Jeromin.
Jason: And I’m Jason Youngstrom, back in the studio!
Kerrin: Jason! Welcome back to the studio, so glad to have you here with me while Taylor is out on an assignment this week.
Jason: Always happy to travel to the sound booth! And today, it sounds like this episode is traveling too. By air, water, and … [hold for suspense] robots!
Kerrin: Oh, I like what you did there. Building the suspense, and giving it everything. That’s right! Today we are talking about sustainable aviation fuel made from corn stover, using 3D printing in marine energy technologies, and—yes— Jason, you want to do it?
Jason: Robots.
Kerrin: Very good. Specifically, though.
Jason: Specifically, we’re talking about how robots can help out the wind industry!
Kerrin: That’s right. Personally, I think when there’s a chance to start with robots, we should—what do you think, Jason?
Jason: Let’s do it!
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Jason: Ok, so robots could help manufacture wind turbine blades—pretty cool!
Kerrin: Very cool! Especially when you consider that the use of wind as a renewable energy source keeps getting more and more important for the nation’s decarbonization goals.
Jason: So, you might be thinking, well haven’t robots been used for a while? And yeah, robots have been used by the wind industry to paint and polish blades. But NREL scientists weren’t just interested in a paint and polish job.
Kerrin: That’s right, yes. Our researchers were looking for more opportunities to use robots in the manufacturing process. And in this case, that means trimming, grinding, and sanding wind blades.
Jason: And ultimately what this means for the wind turbine manufacturing industry comes down to two things: first, that we can improve the consistency of the blade product. And second, we can potentially eliminate difficult working conditions for people.
Kerrin: Right. That is so very important. Workers have to perch on a scaffolding and wear protective suits and respiratory gear, currently, to do these jobs. You can imagine that grinding and sanding would cause a lot of dust and particulate in the air, which, for some, might be considered a tough day at the office. But by automating that step, employees won’t have to risk their safety and health—which is of course, a priority.
Jason: Right. And currently, most blades are imported to the US. But this automation also allows for blades to be manufactured in the US more economically, and ultimately, that leads to more domestic jobs and the better working conditions you were talking about.
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Kerrin: Ok, onto the next story, which, I think, is pretty cool.
Jason: Wait, cooler than robots?
Kerrin: Hmm, debatable, but I think so, personally! Uh, this one has to do with 3D printing and marine energy.
Jason: Oo, the hook is set—let’s dive in!
Kerrin: Ok, so, researchers have discovered that 3D printing, also known as additive manufacturing, can work really well with marine energy technologies, with a little support.
Jason: In 3D printing, a physical object is created from a three-dimensional model using thin layers of material like polymers, metals, or ceramics. With your at-home 3D printers, we commonly see plastics used. But in this application, researchers quickly learned plastics wouldn’t hold up against the ocean’s powerful forces.
Kerrin: They found that stainless steel material and laser metal deposition, which is a type of 3D printing, are the best pair—at least when it comes to creating tidal turbine spars.
Jason: Stainless steel makes sense because it’s corrosion-resistant. But I’m not sure everyone knows about tidal turbine spars—actually, I’m not sure I know about tidal turbine spars.
Kerrin: Yeah, honestly, I didn’t know what they were either, before learning about this story, right? And this is a common thing for our water power researchers to hear about, but not something most of us have heard of or would encounter in everyday life. Spars have a pretty important role for underwater turbines. They are basically the backbone for the turbine blade. It keeps everything in place—which means it needs to be super strong.
Jason: So there’s some super serious testing of this 3D-printed spar at NREL happening right now. NREL engineer Paul Murdy, who is the principal investigator on the study, tells us more.
Paul Murdy: “We started from the very beginning. No idea what printing technology we would use or what material we would use or anything like that, all we had was a geometry and some forces that would be applied. So, we did absolutely everything from start to finish.”
Kerrin: So amazing. This testing team is hard at work to push the spars to their limit. The team will gradually increase the amount of force and weight put on it, eventually putting 1,900 pounds of stress on the spar! That’s 50% more than what it’s designed to handle.
Jason: And Murdy says the only step missing after structural testing is getting it in the water. I think something really important to note with this study is that the spar was designed to be used in tidal turbine technologies that already exist—so it can be put into use really quickly.
Kerrin: Yeah, that is SO important because that means with access to a 3D printer, small coastal communities don’t have to depend on supply chains or traveling long distances to get replacement parts when the parts wear out.
Jason: Exactly – they can print and replace the parts themselves. And that helps build energy resilience and energy security. And that is awesome.
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Jason: We’re at our final story of today’s show already?
Kerrin: Crazy how time flies when you’re having fun. Ha – that was totally a hint to our next story.
Jason: Well, I think some might call this next story a corny one!
Kerrin: Oh, look at us, just popping out all of the puns! Ok, folks, we’ll get you caught up here. We’re talking about sustainable aviation fuel— or planes powered by agricultural waste, and specifically corn stover.
Jason: OK, that’s pretty cool. So NREL has created a deacetylation and mechanical refining process, known as DMR, that prepares corn stover for ethanol fermentation using a gentle alkaline bath and a not so gentle, mechanical shredder.
Kerrin: Apparently, these two combined, they are essential, this process, for accessing the energy-dense sugars locked inside corn stover—stover is basically all the leaves, cobs, and stalks left over after harvesting. Using the plant’s stringy fibers—instead of its fruit or seeds—results in something called cellulosic ethanol.
Jason: Right – and eventually, that cellulosic ethanol can be turned into sustainable aviation fuel. And when you compare it to conventional jet fuel, ethanol made from corn leaves, stalks, and cobs reduces emissions by a lot.
Kerrin: Which is why a company called SAFFiRE Renewables plans to use NREL’s DMR technology to turn agriculture residue into a scalable biofuel business in Kansas.
Jason: The ethanol made at that plant in Kansas will help make sustainable aviation fuel that has a carbon footprint 83% lower than conventional jet fuel.
Kerrin: Wow, 83%--that is huge! This all sounds so great. So we all might be wondering, why hasn’t cellulosic biofuel been a thing before this?
Jason: Well, before NREL’s DMR tech entered the scene, there were some serious challenges. Old cellulosic biofuel technologies used highly specialized equipment that relied on acids, heat, and high pressures to break down the plant material. But their extreme operating conditions created persistent headaches at industrial facilities. The acids corroded expensive equipment, and clogs formed as the shredded stover was fed into high-pressure reactors.
Kerrin: Exactly, so it was really difficult to scale facilities to process thousands of tons of biomass a day. The DMR technology relies on noncorrosive chemicals to lower toxicity and uses nonpressurized tanks that work at low temperatures—which can lower operating expenses and increase the efficiency of making sugars into ethanol.
Jason: So with NREL’s DMR technology, SAFFiRE’s pilot plant will be able to handle 10 tons of corn stover every day and produce around 300,000 gallons of cellulosic ethanol every year—just to start. It’s an important step to commercializing NREL’s technology. The plant’s purpose is essentially to work out how to scale this process to commercial levels.
Kerrin: Which is important! And, speaking of, frequent flyers are likely familiar with Southwest Airlines—under its new subsidiary called Southwest Renewable Ventures, the airline company chipped in initial funding for this new ethanol plant and will have the opportunity to fuel its aircraft with the sustainable aviation fuel from SAFFiRE’s ethanol.
Jason: And that’s just plane awesome.
Kerrin: Plane, I see what you did there. Another pun.
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Jason: So, robots, planes, 3D printing … these are some cool stories we got to talk about today.
Kerrin: Yeah, I mean, I always think all the stories are pretty cool that we talk about, but you’re right—this episode involved some extra cool tech. Jason, so glad you could join today to talk about it!
Jason: Oh, this was great! Thanks for having me!
Kerrin: Of course, thank you so much everyone for listening in. If you like what you hear, go ahead and give us a review on Spotify or Apple Podcasts. OH! And, breaking news, Transforming Energy: The NREL Podcast is now on YouTube @NRELPR so you can listen to us there, as well. Taylor and I will be back in two weeks with more news from NREL!
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Jason: This episode was adapted from NREL news articles from May 2024 written by Wayne Hicks, Brittany Enos, and Erik F. Ringle. Our theme music is written and performed by Ted Vaca and episode music by Chuck Kurnik, Jim Riley, and Mark Sanseverino, of Drift B-C. 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.
