Umeshita explained that because the concept’s rotary engine is designed to run on carbon-neutral fuel, derived from microalgae, it emits 90% less CO2 than a conventional petrol engine – and it is also fitted with a carbon-capture device at the tailpipe which is said to shave another 20% off.
“So theoretically,” he said, “we can reduce by 110%, so that means as you run, you make the earth cleaner.”
“So we can go carbon-negative, which we cannot achieve with the battery-EV. So that is a very unique pathway. I believe the internal combustion engine can make the environment even cleaner than battery EV.”
Umeshita explained that microalgae is also much cheaper and less energy-intensive to produce than synthetic types of alternative fuel. It also has the added benefit of being compatible with existing production engines and fuel station infrastructure, so could in theory be used from today once Mazda works out how to produce it cost-effectively at scale – “and I believe we are very close”.
However, Mazda must still grapple with the inherent increased emissions of a rotary engine compared with a conventional engine. “The vision car has a rotary engine as a drivetrain, not a generator, and in order to realise that, we need good emission levels in a wider range, from low RPM to high RPM.
