All electricity suppliers maintain a Priority Services Register to enable them to provide help to vulnerable customers. For Aberdeen City and Shire the register is maintained by SSEN (regardless of who you have a supply contract with).
Full details can be found on the SSEN Priority Services Register. Among the additional assistance available is "priority help in the event of a power cut if you rely on electricity for medical equipment”.
Please note that only the contracted bill payer is able to register for priority services. This means that people living in halls of residence or shared flats are not able to access this service.