Energy is everywhere—it just needs to be harvested. Today, energy harvesting–enabled wireless systems are already well established in the commercial building automation sector. Technology providers now offer a wide range of energy-autonomous devices for connected buildings. Using motion, light, and temperature differences as energy sources, they can provide batteryless switches; intelligent window handles; temperature, moisture, light, and presence sensors; heating valves; and smart home systems. The technology, however, is still evolving. New applications of batteryless wireless communications will emerge that enhance the world in many ways, from structural health monitoring and water quality control to forest fire prevention, smart city management, and medical care.