Another set of transmission hitches caused power shutdown in Bohol on December 27, the third time this month.

Betty Martinez, spokesperson for NGCP-Visayas, explained that yesterday’s blackout resulted from the momentary tripping of the 138-kilovolt Ubay-Corella line.

The blackout started at past 1 pm yesterday and lasted for 11 minutes, according to the NGCP.

The three previous power shutdown affecting Bohol had been attributed to hitches in Leyte side of the grid.

The prior blackout was 10 days ago and the first this month was on December 3 which was immediately followed by another round a few hours after resumption of power.

The power interruptions on December 4, December 17 and yesterday were all unscheduled; while the December 3 was scheduled to pave for was in relation to line upgrading activity as a second line, or Line 2, has been added to the Leyte-Bohol grid that supplies electricity to Bohol through submarine cables.

The December 17 power shutdown came in two installments–first, at 9:56-10:31 a.m. and at 11:18 a.m. to 6:00 pm.

The NGCP attributed these to the tripping of Ormoc-Maasin 138kV Line 2 as winds affected Leyte.

Martinez said NGCP-Leyte then sent three patrolling teams along the 114-kilometer Ormoc-Maasin Line 2 to survey the area from Structure 180 to Structure 220.

The first team took charge of Structure No. 180, while the second team proceeded to Structure 220, and the third team surveyed the middle part.

NGCP had earlier explained that the common cause of unscheduled power interruptions is “vegetation” such as coconut fronds, branches of trees, or any even banana leaves touching the transmission lines. This causes load interruptions.

This month’s first and only scheduled power shutdown was on December 3 that was supposedly for 13 hours only- -from 4:00 a.m. to 5:00 pm- -stretched to 20 hours and a half and NGCP managed to restore power only at 12:27 a.m. on December 4, attributing it to bad weather that made it difficult for the NGCP linemen and engineers to undertake the procedure.

An unscheduled power interruption affecting the entire Bohol followed at 1:21 p.m. and NGCP restored power at 2:02 p.m., attributing it to another tripping of the 138kV Ormoc-Maasin Line 2.

In most cases, linemen have to dodge with the weather in Leyte that is prone to typhoons and other weather systems.

Prior to this month’s power interruptions, Bohol had experienced three scheduled and one unscheduled “blackouts” in previous months.

The last unscheduled blackout in entire Bohol prior to December 3 was on November 18 at 9:51 p.m. to 10:47 p.m. when 138-kilovolt Ormoc-Maasin line in Leyte tripped.

The three previous scheduled power shutdown were on June 11, July 9, and March 5.

NGCP shutdown power to Bohol on June 11 from 5:00 a.m. to 6:00 p.m. to facilitate the transfer of wires of Tower 70 along the 138-kilovolt Ormoc-Maasin Line 1 to a temporary structure to facilitate repairs on the tower, in addition to project-related and other synchronized maintenance activities.

Another round followed on July 9 at 5:00 a.m. to 6:00 p.m. due to shutdown of the 138-kilovolt Ormoc-Maasin line to facilitate return of wires from Emergency Restoration System (ERS) structure the repaired Tower 70 in Albuera, Leyte.

A 13-hour blackout was experienced on March 5 from 5:00 a.m. to 8:00 p.m. when NGCP had to shutdown the 138-kilovolt Maasin-Ubay submarine cable line for its annual preventive maintenance including the 100-megavolt-ampere transformer and other equipment at Ubay Substation.

The March 5 power shutdown was supposedly from 5:00 a.m. to 6:00 p.m. only.

The “bad weather” factor in Leyte side was among the priority issues that Gov. Edgar Chatto sought to address when he assumed his first term in 2010 in the subject on power supply.

Chatto then mobilized teams to start researching on the possibility of establishing Bohol’s own power supply, inland.

When Bohol experienced total power shutdown from Leyte for over a month after Supertyphoon Yolanda hit Leyte, the governor drew multi-sector support.

After several consultations with experts, Chatto issued an executive order in January 2014, creating the Bohol Energy Development Advisory Group (BEDAG).

BEDAG initiated the formulation of the Bohol Island Power Development Plan (BIPDP) with the assistance from the United States Agency for International Development-Advancing Philippine Competitiveness (USAID-COMPETE) Project.

The BIPDP, a long-term energy plan for the province, is aimed at ensuring security of supply- -that is, available when needed; ensuring reliability and resiliency that entails climate-proofing of supply; and ensuring affordability.

BEDAG “is an institutional mechanism for planning, implementing, and monitoring of power development initiatives in Bohol”.

It is “a multi-sector group composed of various representatives from the Local Government Unit, Private Sector, Academia, the NGCP, and the three local distribution utilities”.     

In a full council meeting last week, the Provincial Development Council (PDC) presented the power supply projects given consideration by the Regional Development Council.

The projects include the Cebu-Negros CNP 230 kV Backbone Project–Stage 3 is targeted in December 2020; CNP 230 kV Backbone Project-Stage 2 in December 2018; Cebu-Lapulapu transmission line in September 2017; Cebu-Bohol Inter-connection in February 2021; Tagbilaran substation in December 2020; and feasibility study (FS) on Visayas-Mindanao Interconnection.

In the BIPDP load forecasts, “approximately 87 percent of the 67-megawatt power consumption of Bohol is being supplied for by the Leyte-Bohol transmission line connecting the island to the main Visayas Grid”.

Bohol’s total electricity demand ranges from 64 megawatts to 67 megawatts and with the economic growth, it is expected to increase to 75 megawatts by 2019 and up to 113 megawatts by 2043.

BEDAG had earlier “endorsed the transmission plan presented by NGCP where an alternate Cebu-Bohol transmission link shall be provided to ensure connectivity of Bohol to the main Visayas Grid.

This alternate transmission link will also allow export of excess power from Bohol if more generating resources are developed within the island”, as earlier pronounced by the governor.