S&B-77: Is it possible that the RECs from our Project would “age out” so they cannot be utilized by a third party?

The response depends not only on Illinois law but also on the use to which the third party puts the RECs and thus the question cannot be answered in the abstract. For example, the third party could use the RECs for compliance with renewable portfolio standards in another state that limits the vintage of RECs that can be used (even if no such limitations exist for satisfying the renewable portfolio standards in Illinois at present).