The Future of Sustainable Flight

“The technologies for sustainable propulsion solutions we develop today will fly well into the future, so we must set a course that anticipates how these will develop,” said Graham Webb, chief sustainability officer at Pratt & Whitney. “Our focus is to continue the company’s legacy of applying the most impactful technologies and fuels to reduce aviation’s impact on the environment—while continuing to maintain the safety record we’ve established over decades—this is the central tenet of our sustainability strategy.”

 

The approach to sustainable aviation

Pratt & Whitney is shaping the future of sustainable flight by improving engine technologies and fuel efficiencies in its products, focusing on three core elements:

  1. Smarter technology for more efficient propulsion

    The Pratt & Whitney GTF™ engine is the latest evolution of an engine whose revolutionary geared-fan architecture has already enabled up to 16-20% better fuel efficiency for single-aisle aircraft and reduced carbon emissions. Since entering service in 2016, the GTF has enabled aircraft to save more than 1 billion gallons of fuel, and 10 million tons of carbon emissions.

    With the GTF Advantage™ engine for A320neo family aircraft, Pratt & Whitney is stepping up the sustainability credentials of the baseline GTF even further. The GTF Advantage will enable up to 1% better fuel efficiency, along with 4% more takeoff thrust at sea level and up to 8% more takeoff thrust at high-altitude airports. And we are working on a range of other technologies to take the efficiency of next generation GTF engines even further.

    As part of a collaborative project supported by the European Union’s Clean Aviation initiative, Pratt & Whitney is developing a hybrid electric GTF demonstrator, designed to optimize aircraft efficiency across different phases of flight. Known as SWITCH (Sustainable Water-Injecting Turbofan Comprising Hybrid Electrics), the project is also focused on developing Water Enhanced Turbofan (WET) technology, which combined with hybrid-electric propulsion, could enable up to 25% better efficiency in future short and medium range aircraft.  Pratt & Whitney is working closely with teams from Collins Aerospace, Airbus, MTU Aero Engines and GKN Aerospace to advance this project.  

    At the same time, Pratt & Whitney’s advancement of hybrid electric propulsion technology is being accelerated across multiple other demonstrator programs, which involve close collaboration with Collins Aerospace, also a Raytheon Technologies business.  In December 2022, Pratt & Whitney Canada successfully completed the first engine run

     of the company’s regional hybrid electric flight demonstrator. The propulsion system combines a 1-megawatt electric motor developed by Collins Aerospace with a fuel-burning engine specifically adapted for hybrid electric operation and is expected to begin flight testing in 2024 on a modified De Havilland Canada Dash 8-100 aircraft. This powerplant technology will enable more efficient engine performance during the different phases of flight, such as take-off, climb and cruise, and reducing fuel burn and CO2 emissions by up to 30% compared to today's most advanced regional turboprop aircraft.

    “Hybrid electric propulsion technology offers significant potential to optimize aircraft across a range of different aircraft applications, helping our industry meet its ambitious goal for achieving net zero COemissions,” said Jean Thomassin, executive director, New Products and Services, Pratt & Whitney Canada. “With our ground test program now well underway, planned flight testing will enable us to accelerate the demonstration of this next generation sustainable propulsion technology as we continue to expand our collaboration within Canada's aerospace ecosystem and beyond."

    The company is also exploring hybrid electric propulsion for the emerging field of advanced air mobility, which aims to move people and cargo between places not easily served by existing modes of transportation. The Scalable Turboelectric Powertrain Technology (STEP-Tech) demonstrator is aimed at hybrid electric propulsion concepts in the 100-500kW class and addresses a variety of potential applications, such as high-speed electric vertical takeoff and landing (eVTOL), unmanned aerial system (UAS) applications, and blended wing body aircraft.

  2. Supporting the transition to cleaner, non-fossil-based fuels

    Sustainable aviation fuel (SAF)

    Alongside advancing more efficient propulsion technologies, increasing the use of sustainable aviation fuel is of critical importance to achieving the goal of net-zero carbon emissions.

    While all Pratt & Whitney engines are today compatible with SAF blended at up to 50% with conventional kerosene, work is underway to ensure engines will be ready to operate with 100% SAF blends in the future.

    In March 2022, Pratt & Whitney successfully tested the GTF Advantage engine configuration with 100% sustainable aviation fuel and has carried out multiple other tests of 100% SAF in collaboration with Airbus, ATR and Embraer.

    “Advanced aircraft and engine technologies are required to reduce the demand for aviation fuel energy.  Additionally, ’drop-in’ compatible SAF blends up to 100% that are critical for reducing the net CO2 impact of the current legacy commercial fleet, as well as that of modern aircraft by 2050,” said Sean Bradshaw, senior fellow of Sustainable Propulsion for Pratt & Whitney.

    Hydrogen

    Pratt & Whitney is in a good position to help the industry’s use of zero-carbon fuels such as hydrogen, with experience developing hydrogen-burning turbine engines going back to the 1950s.

    The Hydrogen Steam Injected, Inter‐Cooled Turbine Engine, or HySIITE, project explores using liquid hydrogen combustion and water vapor recovery to achieve zero in-flight CO2 emissions, while reducing NOx emissions by up to 80% and reducing fuel consumption by up to 35% for next generation single-aisle aircraft.

    While significant industry investments in fuel infrastructure must take place before hydrogen-powered aircraft take flight at scale, Pratt & Whitney continues to develop innovative hydrogen propulsion technologies as part of its wider strategy for powering sustainable aviation.

    “The key takeaway is that we are actively working multiple innovative approaches to reduce aviation’s environmental impact. Many of these are new and unknown to aviation,” said Webb. “While there are many disruptive startups entering this space, they lack the decades of experience and expertise that we possess at Pratt & Whitney.”

  3. Sustainability through greener operations

Pratt & Whitney has also invested in sustainability at its own facilities – an approach that is evident in two new sites in Carlsbad, California, and Asheville, North Carolina.

The Asheville site, which includes an advanced casting foundry and airfoil production facility, has met or exceeded goals for greenhouse gas, water and waste. It also has several sustainability initiatives underway that implement best practices for wastewater, energy and greenhouse gases.  

The Carlsbad facility is reducing its carbon footprint through an on-site heat reclamation system, and it is pursuing on-site power generation. The facility focuses on research of next-generation ceramic matrix composites – materials that could revolutionize the components that operate in the fierce heat of engines’ hot sections.

As part of Raytheon Technologies, Pratt & Whitney sets regular Environment, Health & Safety (EH&S) goals, including targets to reduce greenhouse gas emissions, water usage, and waste. Read more about Raytheon Technologies’ 2025 EH&S sustainability goals here.

“There will be no ‘silver bullet’ for overcoming the enormous challenges the aviation industry faces to reduce CO2 emissions, however we are taking serious steps to address the sustainability challenges,” said Webb. “Through constant innovation and collaboration with industry partners around the globe, we at Pratt & Whitney are determined to deliver our vision of a smarter, cleaner and greener future for aviation.”