In electric power: those services that are necessary to support the transmission of capacity and energy from resources to loads while maintaining reliable operation of the transmission system in accordance with good utility practice and the Grid code to be adopted in accordance with this Act [Section 4(b), Electric Power Industry Reform Act of 2001; Section 4(e), Rules and Regulations to Implement Republic Act No. 9136, Entitled “Electric Power Industry Reform Act of 2001”]
Note: The IRR adopts the definition under the law, except for an adjustment to the writing style (reference to “the Act” instead of “this Act”).
In renewable energy: support services which are necessary to support the transmission capacity and transmission of energy from resources to loads towards maintaining power quality, reliability, and security of the grid through frequency regulation and contingency reserves, reactive power support, black start capability, and other services as may be determined by the Energy Regulatory Commission (ERC) [Section 3(a), Rules and Regulations Implementing Republic Act No. 9513]
In electric power, energy storage: those services that are necessary to support the transmission of capacity and energy from resources to load while maintaining reliable operation of the transmission system in accordance with good quality practice and the Grid Code [Section 2.1, DOE Department Circular No. DC2023-04-0008, Prescribing the Policy for Energy Storage System in the Electric Power Industry]
Note: Under the EPIRA of 2001 and RE Act of 2009, the term is referred to as “Ancillary Services” only, without the acronym.