The Aviation Sustainability Center is a cooperative aviation research organization co-led by Washington State University and the Massachusetts Institute of Technology. The coalition works to create science-based solutions for the aviation industry’s biggest challenges.
You’ve been an academic researcher in sustainable aviation for decades. What led you to your particular in this subject, particularly in the context of this industry?
I grew up in Dayton, Ohio, which has a strong aviation culture due to the Wright brothers; this sparked my interest in aviation early on. In college, I became more involved in sustainability, and these two passions eventually merged. My interest was driven by both science and environmental concerns. Many people in the industry are now recognizing the substantial carbon footprint of aviation, especially if they travel frequently.
My lab plays a role in the pre-screening program for sustainable aviation fuels. Before entering the formal qualification process, many institutions come to us with samples. We've received around 300 samples from approximately 37 different institutions, mostly startups. We collaborate with all major engine companies and airframers. Additionally, I'm involved with the Commercial Aviation Alternative Fuels Initiative (CAAFI), a public-private partnership with roughly 500 institutions and thousands of members, focusing on the commercialization and dissemination of information on sustainable aviation.
Who are the members involved in the FAA ASCENT coalition, and what is its primary purpose?
The FAA’s ASCENT program focuses on local air quality, energy, and noise emissions. It's composed of 16 universities that collaborate on everything from emissions and noise improvement to SAF through efforts to increase blend limits and increase the number of qualified pathways to produce SAF. Since its inception in 2014, ASCENT has funded over 100 projects. ASCENT's advisory committee includes major aviation stakeholders like Airbus, Boeing, GE Aviation, Rolls-Royce, and Pratt & Whitney.
The aviation industry is hugely criticised for its environmental impact, but many people rebut this and claim it can be overstated. What exactly is the true extent of the industry’s contributions to air quality and the climate?
Aviation contributes roughly 2.5% to 3.5% of total anthropogenic emissions. However, aviation emissions are challenging to abate and are expected to grow as the industry expands. Other sectors are decarbonizing, so aviation's relative contribution to emissions is projected to increase significantly, possibly up to 25%. This makes early and sustained efforts in aviation sustainability crucial.
Commercializing SAF is particularly challenging and expensive. Initial commercialization involves substantial investments, often hundreds of millions of dollars, to produce small batches of fuel for testing. The entire process from initial approval to building commercial facilities can take decades and requires overcoming significant financial and regulatory hurdles.
Given the need for decarbonization and the extent of these challenges, what kind of legislation or government intervention will be necessary?
Two recent legislative measures are significant.
The EU and UK have SAF mandates that require a certain amount of SAF production, with penalties for non-compliance. In the US, the Inflation Reduction Act provides financial incentives for SAF production, which is helping to stimulate the market. These measures are changing the economics of SAF production, encouraging producers to maximize SAF yields over other renewable fuels like diesel. However, there are still debates about whether these incentives are sufficient.
Industry voices often call for more support, but quantifying the exact needs is complex.
More incentives might be necessary to drive down costs and accelerate the commercialization of SAF technologies in the long run. The idea that SAF won’t be sufficient to propel most commercial aircraft is a misconception. SAF typically has higher energy content on a mass basis than conventional fuels, meaning you burn less fuel. We've worked with Boom Supersonic to design their aircraft more efficiently around SAF properties. While the benefits are significant, the process of integrating SAF is still ongoing.
In your opinion, who are the companies leading the way in sustainable aviation and setting the standard for the rest of the industry?
Neste and World Energy are currently the largest SAF producers. World Energy in Paramount, California, has been supplying SAF to airports like LAX for a long time. Neste is the largest global producer of SAF and supplies significant amounts to the US. Other noteworthy companies include Montana Renewables, LanzaJet, and the technology provider, Topsoe, which are making significant strides in SAF production.
In terms of manufacturers, many are actively developing new products to accommodate SAF. Collaborations within the industry, such as the ATAG and IAEG and working group, are also driving advancements in sustainable aviation. The dedication of airlines is promising. Alaska Airlines, United Airlines, Southwest, American Airlines, and Delta are making significant investments in sustainability initiatives.
Electric vehicles (eVTOLs) are positioning themselves as one of the answers to the industry’s sustainability problems, so are receiving substantial investment and support. In practice, how much potential do you believe eVTOLs could have in the long term?
eVTOLs hold promise for areas for shorter hauls, providing a sustainable option for regional and urban mobility. However, the majority of aviation emissions come from long-haul, wide-body aircraft, which eVTOLs cannot address due to their range limitations. Batteries are not a feasible solution for these larger aircraft and longer routes. Therefore, while eVTOLs can help in specific markets, they won't significantly impact the overall emissions from aviation.
