To What Extent Can Sustainable Aviation Fuels (SAF) Mitigate the Environmental Impact of Flying?
by Mike McCurdy and Angus Reid-Kay (ICF) … Since SAF is operationally identical and certified as “Jet-A1” fuel, no changes are required in aircraft or engine fuel systems, distribution infrastructure, or storage facilities. That allows SAF use as an interim—and long-term—solution to decarbonizing the aviation industry, while electric and clean hydrogen powertrains are developed, tested, and deployed and ground infrastructure is built.
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SAFs provide a far greater array of value compared to conventional fuels, including environmental benefits, economic benefits, social value, and increased potential for energy security. In the short-to-medium term, the four types of gas turbine engines used in aircraft are well-known, tried, and tested after 50 years of development and refinement. These engines have proven to be dependable, viable, and have an enviable power-to-weight ratio. Therefore, coupling this mature technology with SAFs presents a pragmatic and realistic choice for reducing the sector’s CO2 emissions where global aviation is likely to be reliant on liquid fuels for many years to come.
In addition to the environmental benefits outlined above, SAFs usually contain fewer impurities—most notably sulfur and aromatic carbons—such that existing engines produce significantly less sulfur dioxide and particulate emissions compared to operation with conventional jet fuel. Reductions in these contaminants allow land-based power plants using aero-derivative turbines to significantly increase their maintenance intervals. While additional testing is required, preliminary testing indicated that neat SAFs fuels have the potential to notably reduce engine operating temperatures, increasing power while reducing maintenance requirements.
SAFs constitute a more diverse, global geographic fuel supply. ICF’s Fueling Net Zero report estimates between 5,000-7,000 global refineries are needed to produce the required volume of SAF to improve energy security and resilience for many nations. That renewable technology presents economic and social opportunities, including rural jobs, associated economic growth, and the potential for poverty and inequality reduction—particularly within developing countries. ICF’s report estimates that the SAF requirements will create or sustain up to 13.7 million jobs and will require a total investment of 1.1-1.4 trillion USD, which per year represents 6% of annual oil and gas investment.
Risks and challenges to overcome to increase uptake levels
Lack of commercial facilities: Only one of the seven approved technology pathways, Hydroprocessed Esters and Fatty acids (HEFA), has been used to produce SAF for commercial sale. While technical challenges can be substantial, commercial facilities face challenges with feedstock availability, price volatility of fossil jet fuel, and other traditional business trials. Operating commercial analogs are critical to attract equity investment in the space as well as secure debt financing for the construction and operation of new facilities, particularly in the absence of loan guarantees or other government support for development.
Difficulties in monetizing the benefits of SAF: Feedstock costs and the processing costs of waste feedstocks such as municipal solid waste are generally higher than the cost of crude oil at current market prices. These increased costs result in a product that is generally considered to be between two and seven times more than that of jet fuel derived from conventional fossil fuels. Global blending standards and energy security policies have enabled the construction of several SAF production facilities to date, but construction has been slow given limited commercial opportunity. Recent GHG reduction policies—such as the California Low Carbon Fuel Standard that allow producers to monetize GHG reductions—have been critical in incentivizing the private sector to construct new SAF facilities that are coming online in 2021 and beyond.
Fuel is generally the largest single operating cost for airlines—around a third of their costs—so fuel-saving measures are typically a key focus for airlines. Although SAFs’ life-cycle carbon emissions are much lower than conventional fossil-based sources, SAF is currently more expensive and hence the tradeoff airlines face. By 2050, however, ICF estimates the average industry cost will be $760-$900 per ton SAF, which is comfortably within the range of historical fossil fuel prices. Furthermore, although SAFs account for a very minor share of the commercial aviation fuel market to date, the number and size of SAF offtake agreements between airlines and fuel producers is growing. Partnerships include JetBlue and SG Preston, Finnair and Neste, KLM and SkyNRG, United Airlines and World Fuels.
A call for policy support
Strong support is needed to shift emphasis from carbon-based fuels to sustainable, low-carbon options as soon as possible. An International Council on Clean Transportation (ICCT) paper suggests that a precedent for anticipating some of the immediate challenges might be drawn from the journey taken in switching to advanced alternative road fuels. Potential barriers can be overcome through policies and incentives such as mandates, fiscal incentives, sovereign guarantees, decarbonization programs, and grants. Procurement contracts and associated measures can and have helped improve the feasibility of SAF projects and mitigate some of the risks associated with SAF production. Tax regimes and specific financing should also be considered to help reduce operational costs and boost investment in SAF projects to accelerate projection and deployment.
Special consideration
The incremental gains in technical performance that SAF can offer on their own are unlikely to increase uptake to the level necessary to address global climate change. However, smart policy, regulatory, and economic support for SAF production and use has the potential to provide significant benefits in combating climate change, creating rural jobs, securing our energy supply, and reducing the impact of waste on our natural environment. In all future scenarios, ICF predicts that SAF will be central to the industry’s commitment to reach net-zero carbon emissions by 2050. READ MORE
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