Spotlight |
Hydropower enables renewable integration
Recent power cuts in the Philippines have demonstrated why modern energy systems need to get to grips with the integration of renewable technologies.
by Aboitiz Renewables acquired the 797MW Caliraya- Botocan-Kalayaan Hydroelectric Power Plant (CBK HEPP) complex in Laguna from the Philippine government. The so-called Thunder Consortium, composed of Aboitiz Renewables and Japanese firms Sumitomo Corporation and Electric Power Development Co, won the bidding process for privatisation in July 2025. The complex, particularly its Kalayaan pumped storage units, has been described as a critical energy buffer for the Luzon grid. Its ability to store energy and rapidly dispatch power strengthens system stability, provides essential ancillary services, and supports the integration of renewable energy sources.
Aboitiz Renewables says as the country expands its clean energy portfolio, the facility is expected to play a key role. While Philippine President Ferdinand Marcos Jr underscored the strategic importance of the handing over of the CBK HEPP complex as being “a deliberate step” towards an energy system that is steadier in operations, smarter in design, and future proofed.
Challenges System integration has emerged as a central challenge
System integration is a central challenge for power systems with growing shares of variable renewable energy. Image: Shutterstock AI
A DECREASE IN SOLAR POWER generation led to a series of rotating brownouts across The Philippines during May 2026. With fears power cuts would last for up to seven hours across two main grids, the National Grid Corporation of the Philippines issued a red alert. According to the country’s Energy Regulatory Commission (ERC), the cushion between supply and an elevated demand in late afternoon shrank due to solar power generation tapering off leading towards the evening. “We are not simply facing an afternoon and early evening shortage,” ERC Chairperson and CEO, Francis Saturnino C. Juan, explained. “We are facing a flexibility shortage in the hours after the sun goes down.” As Suiee Suarez, Vice President for Corporate Affairs at AboitizPower said this isn’t “an indictment against solar power generation” but a lesson on having and sustaining a flexible and diversified power mix, where the limitations of one technology can be backed up by another technology that is ready, available, and dispatchable in a matter of minutes.
Earlier in 2026, in efforts to help build a resilient, inclusive, and forward-looking energy system, a consortium led
10 | September 2026 |
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in power systems with growing shares of variable renewable energy (VRE). However, according to Ahmet Hakan Özkan, high hydropower penetration does not automatically translate into smooth integration. His recent study has examined why hydro-dominant electricity systems continue to face integration and flexibility challenges as wind and solar shares increase. It focuses on the fact hydropower operation is shaped not only by installed capacity, but also by hydrological conditions, transmission constraints, operational rules, and long-term planning priorities, all of which can limit real-time balancing capability. In his research, Özkan develops a system-level conceptual framework that distinguishes between technical flexibility and effective system flexibility, highlighting temporal, spatial, operational, and institutional constraints that shape hydropower’s real- world balancing capability.
Using Canada as a case study, the analysis shows how seasonal hydrology, geographic separation between generation and demand, operational restrictions on hydropower assets, and planning inertia can limit the system’s ability to absorb VRE variability, despite favourable resource endowments. Özkan claims his findings demonstrate that
hydropower provides valuable but conditional flexibility and cannot function as a standalone solution for renewable integration. Effective scaling of wind and solar requires coordinated flexibility portfolios that combine hydropower with complementary infrastructure, storage, demand-side flexibility, and advanced system operation.
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