LISTA is aimed at establishing a robust, resilient and reliable electricity highway capable of transmitting quality power to the consumers.
The program will also complement capacity additions programmed for the next decade and map out critical infrastructures for the full implementation of Open Access Transmission Service (OATS) and the Wholesale Electricity Spot Market (WESM).
Transco said LISTA is needed to be able to address the challenges confronting the power sector, particularly in Luzon.
With the economy expected to grow by 4.5 percent and a corresponding increase in electricity demand by 7.4 percent, the Luzon grid’s 2003 peak demand of 6,454 megawatts (MW) will increase to 13,280 MW by 2013.
Transco said the current reserve capacity of 2,921 MW is expected to be depleted in two years’ time, or by 2006.
The concentration of generation sources is in the northern and southern parts of Luzon, while 56 percent of the total load is within Metro Manila area. Northern and southern Luzon share 23 percent and 21 percent of the load, respectively.
Transco noted that transmission line constraints are still one of the challenges being faced by the company. "The concentration of more than half of the total load of Luzon in Metro Manila which is being supplied by generating plants located in the northern and southern parts of Luzon, has created bottlenecks in some heavily loaded transmission lines," it said.
It said the commissioning of lined-up generating plants would further create transmission choke points in both the northern and southern transmission corridors. "These prevent optimum dispatch of power plants and may trigger system disturbances unless new transmission lines are installed," it added.
The Luzon grid supply interdependence shows that Metro Manila imports its power requirements from northern and southern Luzon. The latter is still being augmented by geothermal generation coming from Leyte island in the Visayas.
Transco also noted that the transmission lines connecting various major and load-end substations total approximately 10,170 circuit-kilometers, while transformation facilities has a total capacity of 20,041 MVA.
It said the concentration of generation sources away from major load centers shows the need for a system capable of handling bulk power delivery both during normal and contingency conditions.
The occurrence of Luzon-wide blackouts averaging once a year since 1983, it said, also requires the strengthening of the identified weak/critical points in the power network.
"Luzon power situation hinges primarily on effectively addressing the long-term power supply requirements, transmission constraints and system reliability problem," it said.