High Power Density Carbon Neutral Electrical Power Generation for Air Vehicles

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Project Term:
07/12/2021 - 07/11/2023

Critical Need:

ARPA-E seeks to mitigate the growing environmental burden associated with commercial air travel at minimum economic cost. The REEACH objective is to develop a disruptive energy storage and power generation (ESPG) system to convert the chemical energy contained in energy-dense carbon neutral liquid fuels (CNLFs) into electric power for aircraft propulsion via electric powertrains and other key systems. Ultra-high conversion efficiency and high specific power and energy are critical for technical feasibility and commercial success of ESPG systems due to CNLFs’ generally either lower specific energies or higher projected cost compared to incumbent fossil-based jet fuels.

Project Innovation + Advantages:

Electric propulsion for air vehicles requires a high-power density and high-efficiency electric storage and power generation system that can operate at 35,000 feet in altitude to meet economic and environmental viability. Tennessee Technological University will combine a stack comprised of tubular Solid Oxide Fuel Cells (SOFCs) with a gas turbine combustor to address challenges faced in all electric propulsion-based aviation. The combined SOFC-combustor concept maximizes power density and efficiency while minimizing system complexity, weight, and cost. By eliminating components and subsystems typically found in fuel cell-gas turbine hybrid systems, this design provides operational flexibility with a rapid response to flight and load conditions and enables system startup in less than 30 minutes. This elegant and revolutionary SOFC-combustor concept meets specific power and energy requirements to enable economically viable net-zero greenhouse gas emissions for long-range electric commercial aviation. The deliverables for this Phase 1 project are demonstration of a 1 kW SOFC-combustor and the design of a 5 kW ESPG system.

Potential Impact:

Electrified aviation propulsion systems have the potential to achieve ultra-high fuel-to-propulsive power conversion efficiencies compared with existing turbofan and turboprop systems.


A high specific power electrified propulsion system framework could enable net-zero carbon aviation by facilitating the transition to carbon neutral liquid fuels (CNLFs) while meeting all mission requirements.


This program could ensure U.S. technology leadership in ultra-high efficiency aircraft propulsion systems capable of exploiting CNLFs.


The developed ESPG sub-system could provide the foundational technology for a new industry in ultra-high efficiency propulsion systems while improving the competitiveness of the existing air transportation industry by reducing fuel costs.


ARPA-E Program Director:
Dr. David Tew
Project Contact:
Prof. Rory Roberts
Press and General Inquiries Email:
Project Contact Email:


Wright State University
Oak Ridge National Laboratory
Raytheon Technologies Research Center
Special Power Sources

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