There will possibly be “islands” of power remaining if the grid goes down for an extended period. Logically, these islands will mostly be near hydroelectric dams or wind farms in rural areas. These localized islands could have their power restored in a few weeks, while it might takes months of even years for power restoration in other areas, depending on the severity of a full scale TEOTWAWKI-type infrastructure collapse. Finding where these islands are will take considerable research. And even if you find a potential “island”, don’t count on it. Circumstances may dictate that power is not available, or that it is all shunted elsewhere by government decree.