Environmental Sensors and Presence Detection
Environmental sensors, presence detection, door contacts and low-frequency wireless endpoints are useful early candidates when assessed using measured light and duty cycles.

Key variables
Sampling interval, sensor wake-up, wireless transmission, installed illuminance and storage loss determine energy margin.
This is a scenario and engineering assessment, not evidence of a released product or deployment.
FAQ
Why assess average power first?
Harvested energy is continuous; storage buffers short peak events.