The ASCEND program supports the development of innovative lightweight and ultra-efficient electric motors, drives, and associated thermal management systems (collectively referred to as the all-electric powertrain) that will help enable net-zero carbon emissions in single-aisle, 150-200 passenger commercial aircraft, such as the Boeing 737. The ASCEND program sets a benchmark of the fully integrated all-electric powertrain system at a power density of ≥ 12 kW/kg with an efficiency at ≥ 93%. Currently, these targets, among others, are beyond the capability of state-of-the-art technologies and will require creative thinking and innovation in the electric motor and power electronics space. The ASCEND performers will work in two phases, delivering the:

• Conceptual designs and computer simulations of the motor, its drive, and their integration, as well as subsystem/component level demonstrations for the proposed key enabling technologies to support the performance projections. Phase I will be 18 months long.
• Development, fabrication, and testing of an integrated sub-scale all- electric powertrain (≥ 250 kW), including its thermal management system. (Successful projects may proceed to Phase II subject to budgetary restrictions.)

Air travel is responsible for a growing portion of U.S. energy usage and associated greenhouse gas (GHG) emissions. In 2017, air travel in the U.S. consumed nearly 3.5 quadrillion BTUs of jet fuel and accounted for about 175 million metric tons of CO2 or about 2.6% of domestic GHG emissions. It is estimated that narrow-body aircraft, such as the Boeing 737, are responsible for nearly half of aviation-related GHG emissions. Consequently, a decarbonized, B737-like aircraft with electrified propulsion would provide the greatest impact on GHG emissions from a single aircraft type. ARPA-E seeks to mitigate the growing environmental burden associated with commercial air travel at minimum economic cost by developing elements of an ultra-high efficient aircraft propulsion system that uses carbon neutral liquid fuels (CNLFs). Current electric powertrains do not have high enough power density and efficiency to enable competitive and fully decarbonized aviation for the narrow-body class of aircraft. It is anticipated that the developed lightweight and high efficiency all-electric powertrains will find direct application in the emerging urban air mobility, unmanned aircraft aerial vehicle, and select regional aircraft markets. These markets are likely to be the first adopters before the technology scales to a single-aisle aircraft.

The ASCEND program has the potential to accelerate innovations and cause disruptive changes in the emerging electric aviation field.