Position Paper: Voltage Change is not Energy Consumption

Energy-harvesting sensors utilize local, ambient energy resources to operate and thus eliminate the need for batteries. A key challenge for such systems is avoiding power failures during application execution. Energy-aware runtimes avoid such failures by reasoning about the task's energy consumption and the current energy available to the system. However, the energy consumption estimates profiled by prior work fail to account for incoming energy, producing incorrect energy consumption estimates which could lead to power failures and missed deadlines. This work analyzes the impact of incoming energy on the profiled energy consumption and argues that future energy-aware runtimes must be mindful of harvested energy when profiling a task's energy consumption.