Line 1522 all the way from Oldenburg to Wilhelmshaven is electrified (15kV 16,7Hz).
Additionally, the route from Sande to JadeWeserPort has also been electrified.
This should include line numbers 1546, 1552 (in part) and 1554 (all 15kV 16,7Hz).
Furthermore, the route trough Sande (immediately north of the station) has been closed and replaced by a new double track alginment.
See screenshot for reference:

For further reference: https://bauprojekte.deutschebahn.com/media/projects/7301/docs/BR_oldenburg-wilhelmshaven-bahnverlegung-sande-201904.pdf