More concerning - can anyone explain why there is such a variation in the results from the DC powered unit vs. the TENG-powered one? The graph at the bottom of the report shows a difference of 30-50ppm between both units when they are sitting side by side on the bench.

The power consumption is the thing, these sensors usually run in the low-digit milliwatt range... and they managed to get it to run on a power generation of 0.5 mW, making the combination of both possible at all.

A low powered co2 monitor is likely a big deal. And one that fits to specific power generation systems is even a bigger deal.