Thanks to the ongoing digital revolution, we are on the verge of transitioning to a hyper-connected world. However, the Internet-of-Things (IoT) devices and remote sensors that promise such a reality require energy. With sustainability as a top priority, the energy source must be abundant, ubiquitous, and renewable. Fortunately, low-grade waste heat (temperatures below 100 °C) could fit the bill provided we develop efficient energy harvesting technologies.
source https://techxplore.com/news/2021-10-resource-exhaust-energy-unprecedented-efficiency.html