As mandated by Republic Act 9136, NPC shall perform the missionary electrification function through the Small Power Utilities Group  and shall be responsible for providing power generation and its associated power delivery systems in areas that are not connected to the transmission system. NPC is also responsible for the operation and maintenance of transmission systems of the provinces of Palawan, Masbate, Marinduque, Catanduanes, Oriental and Occidental Mindoro.

Missionary electrification shall be funded from the revenues from sales in the missionary areas and from the Universal Charge (UC) to be collected from all electricity end-users as determined by the Energy Regulatory Commission.

Small Power Utilities Group (SPUG) Website