MIT’s hybrid-electric plane concept could reduce aviation’s air pollution problem

In the aviation industry, a very positive news has been coming in the context of sustainable and clean energy methods. A team of engineers from the Massachusetts Institute of Technology (MIT) has developed a concept for airplane propulsion that they estimate would eliminate 95% of aviation’s harmful nitrogen oxide (NOx) emissions and thereby reduce the number of associated early deaths by 92%.

NOx is a major source of air pollution and has been associated with asthma, respiratory disease, and cardiovascular disorders. Previous research by MIT showed that the generation of these chemicals due to global aviation results in 16,000 premature deaths each year.

A concept developed by the researchers was inspired by the emission control systems used in ground transportation vehicles. Numerous heavy-duty diesel trucks house post-combustion emission control systems to reduce the NOx generated by engines. This inspired the MIT team to suggest a similar design for aviation, with an electric twist. Interestingly, the seeds of the engineering team’s aircraft concept were laid after the Volkswagen diesel emission scandal in 2015.

In the new hybrid-electric or turbo-electric design, a plane’s source of power would still be a conventional gas turbine that uses fired fuel. But now, this turbine is located in the cargo hold and not on the aircraft’s wings. Rather than directly powering propellers or fans, the gas turbine would drive a generator, also in the hold, to produce electricity. This electricity already powers the plane’s wing-mounted, electrically driven propellers or fans. The emissions produced by the gas turbine would be fed into an emissions-control system, which would clean the exhaust before ejecting it into the atmosphere.

According to the results published by the team, it is predicted that if the system is integrated into a Boeing 737 or Airbus A320 type aircraft, the aircraft will need 0.6% more fuel with the extra weight that will occur.

According to Steven Barrett, professor of aeronautics and astronautics at MIT, the concept design seems much more reasonable and feasible compared to electric aircraft designs. The new design would add some hundreds of kilograms to a plane, as opposed to adding many tons of batteries, which would be over a magnitude of extra weight.

Researchers believe that they can solve the problem of the negative contribution of aviation to air pollution with a hybrid-electric plane concept design. The team is now working on designs for a “zero-impact” airplane that flies without emitting NOx and other chemicals like climate-altering carbon dioxide.

We need to get to essentially zero net-climate impacts and zero deaths from air pollution,” Barrett says. “This current design would effectively eliminate aviation’s air pollution problem. We’re now working on the climate impact part of it.