Presentation Profile
Reducing Aviation's Climate Impact with HEFA-SPK
Currently Scheduled: 10/14/2026 - 1:00 PM - 2:00 PM
Room: Exhibit Hall A4
Main Author
Raj Shah - Koehler Instrument Company, Inc.
- Yesi Doctolero - Koehler Instrument Company, Inc.
Abstract:
Aviation contributes to climate change through carbon dioxide emissions and non-CO₂ effects, including soot-mediated contrail formation. Hydroprocessed esters and fatty acids synthetic paraffinic kerosene (HEFA-SPK), produced by hydroprocessing lipid-based feedstocks, is an established sustainable aviation fuel pathway. This literature review evaluates the potential of HEFA-SPK to reduce lifecycle greenhouse-gas emissions, sulfur-oxide emissions, soot formation, and contrail climate effects while identifying important production, certification, and generalizability limitations.
HEFA-SPK can reduce lifecycle greenhouse-gas emissions relative to conventional jet fuel, but the magnitude depends on the feedstock, land-use accounting, hydrogen and process-energy sources, transportation, and coproduct allocation. Its low aromatic and sulfur content can reduce nonvolatile particulate emissions and the number of soot particles available to initiate contrail ice formation. Changes in nitrogen-oxide emissions, however, remain dependent on engine design and operating conditions.
During the ECLIF3 research campaign, an Airbus A350 operated both engines using neat HEFA-SPK during an experimental cruise flight. Compared with the study’s Jet A-1 reference under similar engine and ice-supersaturated atmospheric conditions, measurements showed 56% fewer contrail ice particles per mass of fuel and 35% fewer soot particles. A separate global model simulation estimated a 26% reduction in contrail radiative forcing; this value was not measured directly and should not be generalized to every aircraft, fuel, or atmospheric condition.
Commercial use must also be distinguished from the experimental flight. ASTM D7566 Annex A2 currently treats HEFA-SPK as a synthetic blending component permitted at up to 50% with conventional jet fuel, after which the finished blend must satisfy the applicable fuel requirements. Overall, HEFA-SPK can reduce both lifecycle and selected non-CO₂ aviation climate effects, but the realized benefits depend on sustainable feedstocks, production inputs, certified blend composition, engine operation, and atmospheric conditions.
