Consumers within the Negros Electric and Power Corporation (Negros Power) franchise could have faced a significant increase in their September 2026 electricity bills because of elevated prices in the Wholesale Electricity Spot Market (WESM).
However, the Regional Secondary Price Cap (RSPC) helped reduce the potential impact of these higher generation costs.
The information was presented by Engr. Joe-Mel S. Zaporteza, Vice President and Chief Operating Officer (COO) of Negros Power, during the company’s press briefing on September 22 at its head office in Bacolod City.
The briefing focused on the Energy Regulatory Commission’s (ERC) regional implementation of the Secondary Price Cap and its effect on the electricity rates for September 2026.
ERC Introduces Regional Secondary Price Cap
On September 10, 2026, the ERC issued Order No. 2026-048 MC, titled:
“In the Matter of the Regional Implementation of the Secondary Price Cap for the Visayas and Mindanao Grids, Retroactive to the August 2026 Billing Period.”
The order addresses elevated WESM prices by implementing the Secondary Price Cap separately across regions. It also provides for the recalculation of high WESM charges and the corresponding billing adjustments.
Previously, the price cap was applied using a system-wide approach that considered the Luzon, Visayas, and Mindanao grids together.
Under the regional approach, each grid is evaluated separately. According to Engr. Zaporteza’s presentation, the previous system-wide calculation could dilute the effect of high prices in the Visayas and Mindanao when lower prices in Luzon were included.
The regional calculation is intended to reflect more directly the sustained price pressures in the affected grids.
Regional Price Cap Reduces WESM Costs
The presentation showed the difference between the average WESM prices in August 2026 and the simulated prices under the Regional Secondary Price Cap.
In the Visayas, the average WESM price was ₱18.59 per kilowatt-hour (kWh). Under the simulated regional price cap, it was reduced to ₱8.47 per kWh, representing a 54% reduction.
In Mindanao, the average WESM price of ₱19.56 per kWh was reduced to ₱8.69 per kWh, equivalent to a 56% reduction.
Engr. Zaporteza’s presentation also compared the number of price cap impositions under the system-wide and regional approaches.
For the Visayas, the system-wide approach resulted in 397 impositions, while the regional approach resulted in 4,833.
The figures were presented to show how the regional mechanism could trigger the cap more frequently in areas experiencing sustained high market prices.
Impact on Negros Power’s Generation Costs
For Negros Power, the presentation showed that the average WESM price under the system-wide Secondary Price Cap was ₱19.8432 per kWh.
Under the regional Secondary Price Cap, the figure was ₱9.8812 per kWh. This represented an approximate reduction of 50%.
However, the RSPC affects only the WESM-related portion of the company’s generation costs.
Negros Power’s generation mix was presented as follows:
- WESM: 23%
- Power Supply Agreements (PSAs): 75%
- Net Metering Exports: 2%
Because WESM accounts for 23% of the generation mix, the regional price cap does not apply to the entire generation charge.
The costs of electricity sourced through PSAs are based on agreements established through the Competitive Selection Process and approved by the ERC.
September Electricity Rates With and Without the Regional Price Cap
The presentation also showed the potential effect of the regional mechanism on Negros Power’s September 2026 residential electricity rates.
The figures presented were:
Under the system-wide scenario, the rate could have increased by approximately ₱3.5550 per kWh compared with August.
Under the regional and staggered calculation, the September rate was approximately ₱0.03 per kWh lower than the August rate.
These figures were presented during the briefing as part of the comparison between the potential system-wide rate and the rate after the regional recalculation.
Supply Conditions Contributed to Higher WESM Prices
According to Engr. Zaporteza’s presentation, the elevated WESM prices in August were linked to tight electricity supply conditions in the Visayas and Mindanao.
The presentation recorded:
- 652 hours of red alerts
- 89 hours of yellow alerts
It also showed that August experienced preliminary figures of 20 days of maximum load dispatch (MLD).
The average WESM price was presented at ₱19.69 per kWh before the Regional Secondary Price Cap and ₱9.88 per kWh under the regional calculation.
When available electricity supply becomes tighter, market prices can increase as more expensive generation sources are needed to meet demand.
Price Cap Helps Manage Sudden Rate Increases
The Regional Secondary Price Cap helps reduce the impact of sudden or prolonged increases in WESM prices. However, it does not guarantee that generation costs will remain fixed.
WESM prices may increase or decrease each month depending on electricity supply, demand, and market conditions.
The RSPC will continue to apply unless the ERC issues a new order or repeals Order No. 2026-048 MC.
For Negros Power consumers, the regional mechanism helped prevent the potential generation-cost increase reflected in the system-wide September scenario.
However, electricity rates remain affected by several factors, including supply availability, market conditions, contracted power costs, and regulated charges.
Consumers are encouraged to monitor their electricity bills and follow official advisories for updates on future rate adjustments.
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