A telecommunication system is described that allocates backup power to telephones based on telephone usage. When power to the telecommunication system from a primary source, such as from an electrical utility company, is lost, a backup power source is used to keep the telecommunication system functioning. Because the backup power source has a limited amount of energy, only telephones with a high priority are fully powered. Other telephones are provided with reduced power or receive no power. As the energy level of the backup power source is reduced, the telephone priorities are adjusted.