Sustainable Water-Injecting Turbofan Comprising Hybrid-electrics
▶Summary
The SWITCH project is an ambitious initiative aimed at addressing the challenge of achieving climate-neutral short- to medium-range air transport by developing a revolutionary sustainable gas turbine propulsion system. This project is tightly aligned with the strategic goals of the Clean Aviation program, which seeks to foster innovation and sustainability in the aviation sector. The primary objectives of the SWITCH project are improving fuel burn and energy consumption by 20% and achieving a 50% reduction in the climate impact of both NOx emissions and contrails, compared to a state-of-the-art engine, hereby significantly reducing the three major warming effects of aviation on the climate CO2, NOx, and contrails. This 20% reduction in fuel burn meets the foreseen contribution from propulsion system side to the -30% goal on aircraft level as laid out in the Clean Aviation Strategic Research and Innovation Agenda (SRIA). To achieve these objectives, the project develops the Dual-spool-hybridized heat recovering Second-Gen Geared Turbofan, which features a dual-spool hybrid-electric architecture, combining two Collins Aerospace megawatt-class electric motor generators within a Pratt & Whitney GTF engine, introduces Waste Heat Recovery to further improve thermal efficiency beyond the 2nd Gen GTF, and a low-emissions combustor to reduce NOx and nvPM emissions. The development of lightweight multifunctional structures and an optimized nacelle and thrust reverser support the integration of novel technologies into the powerplant. Local air quality and noise levels around airports are improved through electric taxiing. The propulsion system will be compatible with 100% drop-in Sustainable Aviation Fuel (SAF) and its principle is suitable for powerplants that burn hydrogen. It addresses all climate-relevant market segments: short-, medium-, and long-range. The SWITCH project is conducted by a global consortium, involving aircraft, engine and system OEMs, key tier I suppliers and leading research institutes in combustion and propulsion. This unprecedented collaborative effort will leverage synergies between European and national programs, ensuring that the project is well-placed within the context of the Clean Aviation initiative. In 2026, SWITCH matures the dual-spool hybridized turbofan to Technology Readiness Level (TRL) 5 through ground demonstration of the full propulsion system, and the waste heat recovery concept to TRL 4 through validation of its key enabling technologies. In Phase 2 of Clean Aviation, the dual-spool hybrid-electric configuration is flight tested and matured to TRL 6 by 2030, and Waste Heat Recovery System demonstrated to achieve TRL 5 by 2030. Results from SWITCH will reinforce confidence in the climate reduction potential of the Dual-Spool- Hybridized heat recovering Second-Gen Geared Turbofan and form the technological foundation to enable the innovation to enter the market by 2035. This concept will significantly reduce aviation's climate impact, contributing towards the European Green Deal's goal of climate neutrality by 2050. Overall, the SWITCH project is ready to make a substantial contribution to sustainable aviation, driving innovation, and reducing the environmental impact of air travel.