Importance of System Frequency as Indicator
- System frequency reflects real-time power system balance; it drops when load exceeds generation and rises when generation exceeds load.
- Large frequency deviations cause equipment damage and potential power system failure.
- Adequate reserves are necessary to manage frequency deviations promptly to avoid instability.
Frequency Response and Regulating Reserve Providers
- The performance of frequency regulating reserve providers directly impacts system efficiency.
- Fast response times by these reserves ensure a stable and reliable grid.
Challenges of Renewable Energy Integration
- Renewable energy sources, such as wind and solar, add variability to power output due to their intermittent nature.
- Increased variability escalates the need for ancillary services to maintain grid stability.
Battery Energy Storage System (BESS) as a New Technology
- BESS is an emerging technology capable of providing Frequency Control Ancillary Services (FCAS).
- FCAS covers Contingency Reserve (Primary Reserve) and Frequency Regulation (Secondary Reserve).
Definition and Role of Frequency Control Ancillary Services (FCAS)
- FCAS ensures supply and demand balancing in the power system through frequency control.
- Different electricity market structures characterize FCAS based on event types, response times, activation methods, and directional frequency control.
Benefits and Global Adoption of BESS
- BESS improves grid operation efficiency.
- It is already deployed by system operators in advanced and complex power grids worldwide.
Grid Management Committee (GMC) Recommendations
- GMC recommends classifying BESS as a new source of FCAS, specifically:
- Contingency Reserve (Primary Reserve)
- Frequency Regulation (Secondary Reserve)
- GMC further recommends exempting BESS from System Impact Study (SIS) subject to siting and capacity limits per grid (Luzon, Visayas, Mindanao).
- BESS capacity must not exceed the required frequency regulating reserve in a location.
Rationale for Exemption from System Impact Study (SIS)
- SIS assesses potential impacts of new grid elements on system performance.
- Reasons for exemption include:
- Power flow analysis concerns are manageable by capacity allocation in transmission lines.
- BESS uses direct current with negligible short circuit risk.
- BESS is static and used solely for frequency regulation, posing no instability risks.
Conditions on Exemption and Certification
- Exemption does not waive required performance testing by the National Grid Corporation of the Philippines (NGCP).
- NGCP must certify the ancillary service provider as qualified.
Clarification on Frequency Regulating Reserve Provisions
- Paragraph 6.6.1.2 of PGC Amendment No. 1 clarified to align with paragraphs 6.6.2.1 and 6.6.2.2:
- Frequency Regulating Reserve includes:
a. Primary Response (automatic frequency-sensitive mode - free-governor mode)
b. Secondary Response (automatic generation control or manual adjustments via dispatch instructions from SO)
- Frequency Regulating Reserve includes:
Current Contingency Reserve Capacity and Impact of BESS
- Luzon currently has a firm contracted capacity of 340MW for contingency reserve.
- Additional contributions from non-firm providers including BESS add needed power supply.
- BESS inclusion promotes a more competitive power industry.
Final Resolutions by the Energy Regulatory Commission (ERC)
- Official adoption of GMC's recommendations:
- Classify BESS as new FCAS source (Primary and Secondary Reserves).
- Exempt BESS from SIS subject to siting and capacity constraints.
- Require NGCP performance tests and certifications.
- Clarify PGC provisions on frequency reserves to avoid confusion.
- Resolution effective 15 days post-publication.
- Copies furnished to relevant government and industry bodies for implementation.