well, they didn't take into account the energy produced by the ambient temperature (the exact temperature was not mentioned in the article, and the paper is beh

well, they didn't take into account the energy produced by the ambient temperature (the exact temperature was not mentioned in the article, and the paper is behind a paywall, but they do say it was rather high) > [it] instead took advantage of small amounts of excess heat to emit more power than consumed. This heat arises from vibrations in the device’s atomic lattice, which occur due to entropy.