The Philippines transmission grids are prone to natural disasters , aging that causes the steel and wood towers to corrode or decay , and grid security is compromised by squatters and insurgent groups . Squatters , or " informal settlers " , pose a danger to transmission lines and a hindrance to line maintenance , especially in Metro Manila . The Mindanao Grid is prone to sabotage , led by insurgent groups and unknown assailants , and many transmission towers have been damaged or collapsed from consecutive bombings , that may cause a cascading failure of the grid . Damage to several power plants and a transmission line after the April 2017 earthquake swarm in Batangas reflected the need of power resiliency , resulting the Department of Energy to draft a policy to improve power supply resiliency . Also , most transmission infrastructure are aging , having a service lifespan of over 20 years without life extension maintenance . Wood poles remain in use , especially in the 69,000 volt systems , but are prone to decay and natural disasters , especially typhoons and earthquakes , and many are being replaced with more stable steel or concrete poles or a newer wood pole in some places
April 2017 earthquake swarm
2017 Batangas earthquakes
Electricity sector in the Philippines