The local government said that the outage has affected "the entire island", but that emergency generators were working for basic services such as hospitals.
Patricia Hernandez, the mayor of Tenerife's capital, told Cadena SER radio that she expected power to be restored to most parts of the island within six hours. She said authorities were investigating the cause of the outage.
There were no incidents immediately reported from the outage.
Tenerife is part of the Spain's Canary Islands archipelago in the Atlantic Ocean off the northwest coast of Africa.
