Napocor president Cyril del Callar said the generation of these diesel power plants will be slashed from 8.63 percent last year to 6.04 percent this year.
In Cebu, however, the operation of this type of plants will continue due to lack of power supply to meet the rising demand.
Napocor-Visayas official Moses Red said, "We are trying to minimize the use of our diesel plants but in the Visayas, particularly in Cebu, maglisod gyud ta kay dako atong demand."
Red recalled that, last year, Napocor put its two land-based gas turbines in Naga under economic shutdown to save on oil. The two turbines, with a combined capacity of 50 megawatts, are largely dependent on oil.
"They are used as back-up only," said Red explaining that whenever Cebu direly needs for additional supply, these plants are put in operation.
Red said there are six plants currently operating in Naga with the use of diesel and bunker fuel. Napocor has been spending P7 per kilowatt-hour to operate these plants but it sells the power to the Visayas Electric Company at more than P3 per KWH only.
"Alkanse kaayo ta. That is why we have to maximize the use of our geothermal power plants," he said referring to the two thermal plants in Naga that have a combined capacity of 105-mW. He added that one of these plants, which uses coal, was shut down Sunday for maintenance.
The Napocor's plants in Naga are operated and maintained by Salcon Power Corporation.
Del Callar said Napocor has tried to avoid utilizing the more costly oil-fired plants and is shifting its attention to using hydropower and geothermal sources instead.
The volatile nature of crude oil prices in the international market pushes the government to look for alternative sources that would minimize the country's dependence on imported oil products, he said.
Last Sunday, the country's three biggest oil companies, Petron Corp., Pilipinas Shell Petroleum Corp., and Chevron Philippines Inc. raised the pump prices of their products by another 50 centavos.