Learners' everyday ideas about energy often involve energy being "used up" or "wasted." In physics, the concept of energy degradation can connect those ideas to the principle of energy conservation. Learners' spontaneous discussions about aspects of energy degradation motivated us to introduce new learning goals into our K-12 teacher professional development courses. One of our goals is for learners to recognize that since energy degradation is associated with the movement of some quantity towards equilibrium, the identification of energy as degraded or free depends on the choice of the objects involved. Another goal is for learners to recognize that overall energy degradation occurs. We find that teachers' discussions contain productive ideas about energy degradation that demonstrate progress towards our goals. These include (1) the idea that degraded energy can be made useful and (2) the idea that making energy useful requires either effort or energy relocation.