The Power Plant is designed to utilize Semirara Coal in generating electricity. To capitalize on synergies between SMPC's coal mining business and the operation of the Calaca power Plant, SCPC, on December 2, 2009, assumed all of DMCI-HI's rights and obligations under the Agreements executed by and among DMCI-HI, PSALM and SCPC, transferring the right to operate the Calaca Power Plant. On May 4, 2010, full ownership over the Calaca Power Plant was transferred to SCPC. The proximity of the Calaca Power Plant to the Semirara Minesite shall bring a lot of benefits to the Plant including freight cost advantage compared to imported coal. SCPC, as the owner and manager of the Plant, engaged the services of its affiliate, DMCI Power Corporation (DPC), to rehabilitate, operate and maintain the power plant effective June 1, 2010.
Since then, it has successfully managed to rehabilitate both units which improved the generating capacities to perform close to its rated capacity of 600 MW.
The acquisition of Calaca Power plant is in parallel with the DMCI-HI 's synergistic investment strategy, being a forward integration of its coal mining business. Its infrastructure and construction businesses could actively participate in the necessary repairs, maintenance and rehabilitation of the Power Plant.
The 167-hectare power complex is located along the shorelines of Balayan Bay, approximately 250 kilometers by sea from Semirara Island, Antique and about 115 kilometers south of Manila. It is bounded on the north by the National Highway, on the west by Dacanlao River, on the east by Cawong (Bolboc) River and Balayan Bay in the south.
The power plant is composed of two (2) generating units, each with a 300MW rated capacity. Unit 1 was first commissioned by National Power Corporation (NPC) in 1984 and Unit 2, in 1995. It is using Semirara coal to generate power with pulverized coal-fired boilers and steam-driven turbo generators. It can also blend its consumption with imported coal as alternative and heavy fuel oil as standby. Light fuel is used as igniter fuel.
A harbor of 50 ,000 Dead Weight Ton (DWT) capacity unloads Semirara coal or imported coal from ships and barges. The coal is conveyed to the covered coal storage yard, which has adequate capacity for the two (2) plants. The coal is then reclaimed into the semi-enclosed conveyors, then to the crusher and to the silos. It is fed to the pulverizers where it is crushed to a fine (talcum-like) powder before being conveyed by primary air through piping into the boiler furnace combined with secondary air for boiler firing.
The heat of combustion gases, absorbed by demineralized water flowing inside the boiler tubes, generates superheated steam. Steam at 169 kg/cm2 and 538 deg. C is directed to the main turbine and turns it at 3600 rpm. The AC generator coupled to the rotating main turbine converts the mechanical energy into 300MW of electrical power.
The turbine-generator's power output voltage is stepped up from 22 kV to 230 kV, fed into the switchyard and transmitted to the Luzon grid through the Biñan and Dasmariñas transmission lines. Meanwhile, heavy (bottom) and light (fly) ash particles are produced as by-products of combustion. In the past, the heavy or bottom ash (wet technology) was collected and managed in the ash pond. Now 2 units of the company is already shifted to dry bottom ash handling system Unit 1 has been converted and eventually, unit 2 will be converted to dry ash, as well. On the other hand, the light ash or fly ash goes with the gases and collected in the Electrostatic Precipitator for sale to cement companies.
The flue gases are finally released through the high smoke stack where they are dispersed into the atmosphere posing no harm at all to people and environment.
The cooling water used to condense steam in the condenser is drawn from Balayan Bay. After it is used, it is discharged through marine pipes into the discharge channel where temperature is reduced to meet regulatory requirements before mixing again with seawater.