Energy in sensor networks is distributed and non-transferable. Over time, differences in energy availability across the network are likely to arise. Protocols such as routing engines can concentrate energy load at certain nodes. Variations in incident sunlight can produce different solar charging rates at different nodes. Because many sensor network applications require nodes collaborate - - to ensure complete sensor coverage or route data to the network's edge - - a small set of nodes threatened by low energy availability can have a disproportionate impact on the entire network. For example, the loss of a single sink node may render the application unable to communicate with all the other nodes. However, network density provides redundancy that can be exploited to control the distribution of energy load. Multiple possible routing paths may link a node and the sink, or several sinks may exist. Adjusting MAC-level parameters may allow a node to conserve energy by forcing additional load on its neighbors. Inputs from multiple sensors may prove redundant to the application, allowing some sensors to be disabled or operated at reduced fidelity, saving power at those nodes. These choices imply that energy load can be tuned to match availability, and this tuning can extend the useful lifetime of the network. Effective distributed energy management requires network-wide awareness of energy availability and load integrated with algorithms guiding protocols toward states producing longer lifetimes or higher node duty-cycles. Intelligent Distributed Energy Awareness (IDEA) is a sensor network service that can be used by both protocols and applications. Given the current energy availability and a set of protocol states, each with different implications for network-wide energy consumption, IDEA projects future energy availability in order to make the best choice. By simplifying decisions impacting distributed energy availability, it facilitates the implementation of energy-aware services.