Sustainable Aviation Fuel Today (Text Version)

This is a text version of the podcast episode Sustainable Aviation Fuel Today from April 21, 2022.

Mollie Putzig: Welcome to "On the Go" an On Road-Transportation Podcast with Clean Cities. In this episode we're talking about current research and applications of sustainable aviation fuel. To kick us off let's introduce our hosts. I am Molly Putzig.

Joanna Allerhand: And I am Joanna Allerhand. Today we will be joined by two experts from the National Renewable Energy Laboratory. They'll be discussing the benefits of sustainable aviation fuel, also known as SAF, how it is produced and distributed, key stakeholders and current research.

Mollie Putzig: SAF is a near term option that can help de-carbonize the aviation industry. It's produced from renewable feed stocks and has a substantially lower carbon footprint compared to petroleum-based jet fuel. Here to tell you more are Kristi Moriarty and Zia Abdullah. Let's get started.

Kristi Moriarty: I am Kristi Moriarty at the National Renewable Energy Laboratory, and I typically work on infrastructure and giving of fuel from the point of production to the end use. In this case getting sustainable aviation fuel from wherever it's produced at onwards to an airport and to the airplane for flight.

Zia Abdullah: I am Zia Abdullah. I am the Bioenergy Technology Manager. I work with the DOE Bioenergy Technology Office on where is fuels and chemicals opportunities from renewable resources.

Joanna Allerhand: Great. Thank you so much for being here. Kristi, can you get us started by telling us about what sustainable aviation fuel is?

Kristi Moriarty: I sure can. Sustainable aviation fuel, which is also called SAF, I would say it is more broadly defined as a fuel that's made from non-petroleum feedstocks, and it's a near term alternative that reduces emissions from air transportation. For a more refined definition that comes from the International Civil Aviation Organization, which is a United Nations Agency that supports diplomacy and cooperation for air transport worldwide.

They have made a wider definition of the fuel in SAF, with achieved net greenhouse gas emission reductions on the lifecycle basis, respect the areas of high importance for biodiversity conservation and benefits for people from ecosystems, and also contribute to local, social and economic development, and not have competition with food or water. So basically, they want the fuel not only to help aviation but also the communities where the feedstocks are developed and sourced from.

Joanna Allerhand: And you touched on this, but can you expand on what the main benefits are of SAF?

Kristi Moriarty: Yes, probably the most immediate benefit is SAF is a true drop in fuel. When it is blended with the conventional jet A fuel that we use today it can be used in existing infrastructure and aircraft. So that makes it a very near-term viable fuel that's already in use today, and we expect to expand use in the very near future here. So we'll see more of the SAF in use before we see hydrogen or electrification coming into aviation.

And also, worldwide aviation accounts for 2 percent of carbon dioxide emissions and 12 percent of transportation emissions. And neat SAF that's been evaluated by Argonne's, GREET and others has the potential to reduce greenhouse gas emissions by 26 to 94 percent, and that's based on both the feedstock and the technology pathway. Of course, it depends on how much SAF is blended in the fuel with the impact of that reduction is.

Joanna Allerhand: Right. Do you mind clarifying for the listener what the GREET model is?

Kristi Moriarty: The GREET model looks at the life cycle analysis benefits of many different fuels. It's funded by DOE, and it's at Argonne National Laboratory.

Joanna Allerhand: Thank you.

Mollie Putzig: Great. So now we're hoping to talk a little bit about production of SAF. So Zia, could you talk a little bit about how SAF is produced?

Zia Abdullah: SAF is produced by converting renewable feedstock to molecules which are identical to those that exist in conventional jet fuel today. So jet fuel today is called Jet A in the US, and the goal is to for drop in fuels is to make molecules that are identical to existing Jet A. This is done through biological or catalytic technologies that are embedded in processes that are similar to those fuels in conventional petroleum refineries.

The enabling processes here are technologies that funnel the very diverse slate of molecules that are in renewable feedstock into essentially four molecule classes that exist in Jet A. These are called normal-, cyclo-, and iso-alkanes, and aromatics. So in the end SAF, drop in SAF is identical to conventional jet fuel that is used today.

Mollie Putzig: Okay. So what feedstocks are SAF expected to use?

Zia Abdullah: So conversion processes by now have become so versatile that most feedstocks that contain renewable carbon can in principal be converted to SAF. So the renewable feedstock can include woody and herbaceous biomass. It can include municipal solid wastes, and even waste such as sledges from farms, industry, food processing plants and wastewater treatment facilities. All of this material can be converted to SAF.

The Oakridge National Laboratory and the funding from the DOE Bioenergy Technology's Office has published a study called "The Billion Ton Report" and this study concludes that the US can sustainably produce over a billion tons of feedstock, renewable feedstock annually, and most of this feedstock can be converted to SAF.

Mollie Putzig: Sounds like there are a lot of options out there. And who is producing SAF today?

Zia Abdullah: At present in the US SAF is being produced by World Energy in the refinery in Paramount, California. Neste also imports SAF into California from their production facility in Singapore, and Gevo also has a production facility in Silsbee, Texas.

Mollie Putzig: So how much SAF is being produced today?

Zia Abdullah: At present about four and a half million gallons are produced annually in the US, and most of the SAF that is being produced is using the HEFA process. HEFA stands for hydro treated esters and fatty acids. The feedstock for the HEFA process are vegetable oils, waste oils, fats, oils and greases and those can be converted using processes that are very similar to conventional refinery hydro treating to SAF.

Mollie Putzig: So what are DOE's goals for fuel production in the future?

Zia Abdullah: DOE has set very aggressive goals to expand SAF production from about 4.5 million gallons per year today to 3 billion gallons a year by 2030, and 35 billion gallons a year by 2050.

Mollie Putzig: Wow, that's a lot. So what research is being done to expand production and reduce those costs?

Zia Abdullah: So they are all working very hard at this, and this reset is being led by the Bioenergy Technologies Office. They are funding seven new conversion technology pathways from renewable feedstocks to SAF at the national labs and other institutions. And the goal here is to develop multiple options for conversion, and with each of these giving or reducing carbon emissions at least by 70 percent or more related to fossil fuels.

Another goal is to help the existing corn ethanol industry by enabling the ethanol that they produce to be converted to SAF, and by enabling them to reduce their carbon intensity also by greater than 70 percent reduction relative to fossil fuel. In addition, the Bioenergy Technologies Office is also funding already disciplined technology scale of process through their annual funding opportunity announcement. Technology risk during scale up is a significant barrier, and the DOE is working towards overcoming that barrier through their technology scale up strategy. Their goal is to actually build and operate four to five demonstration scale SAF facilities by 2030.

Joanna Allerhand: Now that we've covered how SAF is produced let's talk about how it's distributed. Kristi, where is SAF being used today?

Kristi Moriarty: Yeah, so Zia said there is a production facility in Paramount, California, which happens to be located quite near to Los Angeles International Airport. So since 2016 fuel from World Energy has been delivered and used at LAX without issue. And in 2020 and 2021 we saw the expansion of SAF into several other airports including San Francisco International Airport and Ontario International Airport, which is in California.

And the reason that we see so much of the fuel in California is due to the low carbon fuel standard and the ability for fuel producers to receive the best price for their product. Now as other states pass low carbon fuel standards or something similar to that we should see expansion. And also as Zia said, DOE has these goals of much more expanded production and we'll start to see it in other parts of the country.

And also in 2021 in Colorado at both Telluride Regional Airport in Aspen and Pitkin County Airports SAF has brought in a great distance by truck, and it just shows that you can get that fuel to some pretty remote areas if needed. And those airports are pretty unique in that while they have some regional commercial jets they are dominated by private jets in that area. But we'll continue to see expansion into other airports over time.

Joanna Allerhand: Great, and you mentioned trucks. Generally, how does SAF get from the production facilities to airports?

Kristi Moriarty: Yeah, and that's a great, great question because when you look at Jet A it's not blended, like when we look at our on highway transportation fuels they're blended with additives or maybe gasoline with ethanol. But when it comes to jet fuel this is a different process. So as Zia was talking about production either the SAF could be produced at a petroleum refinery where the renewable feedstock is brought in. And if that occurs, it's just a business as usual. It's certified at a refinery. It goes through the pipelines, terminals and onwards to the airport at it does today.

For SAF that's produced at a standalone plant, which is going to be the more likely scenario analysis that we did at NREL and because of the strict quality standards that apply to jet fuel that we're all so grateful for, it really pointed towards blending Jet A and SAF at the terminal upstream from the airport, and doing all the testing and certifying it as the ASTM D1655 fuel, which is the conventional jet fuel standard for delivery to the airport from the terminals. That's what we've seen happening at San Francisco Airport as they have introduced it there.

Mollie Putzig: So it sounds like there is a lot going on and room for a significant amount of growth in this area. I also wanted to ask about who the key players are and what their roles are in SAF? So Zia, what is the federal government's role for SAF?

Zia Abdullah: The federal government is currently looking at new technology development and scale up of this technology development for demonstration scale. And this is so that the industry can access the very diverse feedstock that's available. This includes sustainable management of wastes in agriculture so that this creates new economic growth opportunities for the country. The government is helping pivot the current ethanol industry to sustainable aviation fuels, and also helping develop new chemical production opportunities along with the fuel, so that the economics of fuel production becomes much more attractive so that more investments are made in this area, and there is greater growth in SAF production.

Mollie Putzig: Great. So Kristi, what is the role of airlines for SAF?

Kristi Moriarty: So with airlines they generally enter into supply contracts with SAF producers, and that doesn't necessarily mean that money changes hands initially if the plant hasn't come online yet, but it gives a guaranteed output for that plant that allows investors to see that there is customers for that product, and helps get those SAF plants built. And in some instances you might even see an airline directly invest into a SAF production company. And as an example, United Airlines invested $30 million in Fulcrum Bioenergy, who has a facility under construction in the Reno area.

And also have consideration too with airlines, you have airlines at the airport, they share the fuel infrastructure and the fuel, once it's in the system it's not directed towards a particular flight. So airlines work together as a fuel consortium and just have to have agreement where there might just be some of the airlines paying for the SAF, but all of the airlines are in agreement that that's allowable at the airport and it's not going to be dictated which particular aircraft that is going to receive the fuel.

Mollie Putzig: And then what is the role on the other side of the coin of the airports for SAF?

Kristi Moriarty: Yeah, so airports don't buy jet fuel, however they do have with their airport authorities emission mandates and environmental goals that SAF can help meet. And like I said, they don't buy the jet fuel, but they do typically, especially at larger airports own the infrastructure which they lease out to the airline fuel consortiums and those are generally operated by fixed base operators.

So what airports have done, particularly those in San Francisco and LAX and the airports that are already using it, as well as Seattle and Port Authority of New York and New Jersey is they have brought together the various stakeholders like the airlines, the fuel suppliers, the terminal, the pipeline owners, those fixed base operators to all come together to understand what the fuel is, what they're going to do, how they're going to get it there. What's the optimal place for blending?

And again, San Francisco, Seattle, Port Authority in New York and New Jersey all did studies on that to figure out and prepare for bringing the fuel to their airports. And even in some cases Seattle and Port Authority in New York, New Jersey in particular also conducted an assessment to see what regional SAF production might look like and the logistics of that and looking at some of the benefits of the circular economy. You can use waste in your area and use the fuel there. So airports definitely have a role to play, even though they themselves do not purchase jet fuel.

Mollie Putzig: That makes sense. Well it seems like there is a lot of great opportunities going on for SAF, and this is really helpful in understanding just the basics and getting a picture of what things look like now and where we're headed. I just want to say thank you so much Zia and Kristi for joining us and helping answer some of our questions.

Zia Abdullah: You're welcome, thank you so much for asking us. My pleasure.

Kristi Moriarty: Thank you for the opportunity.

Mollie Putzig: Thanks Kristi and Zia for joining us and sharing your research and the current market status of SAF.

Joanna Allerhand: Before we wrap up we want to share a quick transportation news tidbit with you. What do you have for us this time Mollie?

Mollie Putzig: Our guest Kristi recently published a report on US Airport Infrastructure and Sustainable Aviation Fuel. This report goes into more detail about current SAF production and distribution. It also provides information about quality standards and certification, as well as blending options. It's a great resource if you want to expand on today's discussion. You can find the report by searching for SAF. That's S-A-F, or look for the link in the podcast description.

Joanna Allerhand: Thanks for sharing that Mollie. That's it for this episode of "On The Go". As we wrap up I want to thank the US Department of Energy's Vehicle Technology's Office and our team here at the National Renewable Energy Lab for their support. Also a big thanks to Brittany Conrad and Vern Slocum, our podcast editors. We couldn't do it without you.

Mollie Putzig: If you want to learn more about Clean Cities and its partnerships to develop affordable, efficient, and clean transportation options to accelerate the development and widespread use of a variety of innovative transportation technologies, visit