Energy is the critical limiting resource to mobile computing devices. Correspondingly, an operating system must track, provision, and ration how applications consume energy. The emergence of third-party application stores and marketplaces makes this concern even more pressing. A third-party application must not deny service through excessive, unforeseen energy expenditure, whether accidental or malicious. Previous research has shown promise in tracking energy usage and rationing it to meet device lifetime goals, but such mechanisms and policies are still nascent, especially regarding user interaction. We argue for a new operating system, called Cinder, which builds on top of the HiStar OS. Cinder's energy awareness is based on hierarchical capacitors and task profiles. We introduce and explore these abstractions, paying particular attention to the ways in which policies could be generated and enforced in a dynamic system.