China is modernizing critical power infrastructure at one of its largest nuclear plants to ensure long-term reliability as electricity demand surges across the region. Hitachi Energy, a global power equipment manufacturer, has been selected to replace and upgrade gas-insulated switchgear at the Daya Bay Nuclear Power Station in Shenzhen. The equipment being replaced has operated for more than 30 years, and the systematic upgrade will occur in phases over an estimated eight-year period to maintain uninterrupted power supply.

Why Does a 30-Year-Old Nuclear Plant Need Such a Major Equipment Upgrade?

Daya Bay Nuclear Power Station has been operating continuously since 1994, generating nearly 15 billion kilowatt-hours of electricity annually. About 80 percent of that power flows to Hong Kong, where it accounts for roughly a quarter of the territory's total electricity consumption. After more than three decades of continuous operation combined with rising energy demand, the plant's critical power equipment is showing its age and can no longer reliably handle the strain placed on it.

The upgrade focuses on gas-insulated switchgear, or GIS, which are the critical devices that control and protect the flow of electricity from the nuclear station to the broader power grid. These 500-kilovolt systems have been in service for more than 30 years and represent one of the most essential links connecting the power station to regional distribution networks. The replacement of all 15 bays will be carried out in phases, aligned with nuclear and grid maintenance windows to ensure continuous power supply throughout the process.

What Makes This Such a Complex Infrastructure Project?

This is not a straightforward equipment swap. The project is considered one of the most complex gas-insulated switchgear retrofit projects globally, with demanding commercial and contractual requirements. The work must meet stringent nuclear safety standards, including nuclear liability considerations, while maintaining the plant's exacting standards for reliability, availability, and operational stability. Hitachi Energy will leverage its extensive service experience with high-voltage products to develop retrofit solutions tailored to the existing customer infrastructure.

The eight-year timeline reflects the scale of the undertaking. Rather than shutting down the plant for a complete overhaul, the replacement will occur in phases to keep the facility operational. This approach requires meticulous coordination with existing maintenance schedules and careful planning to avoid disrupting power supply to the Guangdong-Hong Kong-Macao Greater Bay Area, a region that depends on Daya Bay for stable electricity.

Steps to Understanding Nuclear Infrastructure Modernization

• Equipment Replacement: Hitachi Energy will replace gas-insulated switchgear that has operated for over 30 years with modern equipment designed to handle higher power loads and provide improved reliability and safety margins.
• Phased Implementation: The replacement of all 15 bays will occur in phases over eight years, coordinated with the plant's existing maintenance schedules to prevent service disruptions to Hong Kong and Guangdong Province.
• Nuclear Compliance: The project must meet stringent nuclear safety standards and regulatory requirements, including nuclear liability considerations, making it one of the most technically complex GIS retrofit projects globally.
• Regional Energy Security: By ensuring the long-term reliability of Daya Bay, the upgrade supports stable electricity supply to the Guangdong-Hong Kong-Macao Greater Bay Area, a region with significant population and economic activity.

"We are pleased to participate in the upgrade project at the Daya Bay Nuclear Power Station. The systematic replacement of core high-voltage switchgear that has been in service for more than 30 years is a critical measure to ensure the long-term resilience operation of this 'cornerstone' of energy supply for the Guangdong-Hong Kong-Macao Greater Bay Area," said Liu Tianquan.

Liu Tianquan, Local Service Business Unit Manager in China, Hitachi Energy

How Does This Fit Into China's Broader Nuclear Strategy?

China now operates one of the world's largest nuclear power fleets and is entering a new phase of high-quality development focused on modernizing aging plants while building new capacity. Upgrading aging equipment has become a fundamental pillar in ensuring the long-term safe and reliable operation of nuclear power plants across the country. This investment signals that China recognizes nuclear power as essential infrastructure for supporting emerging power demands, including AI-driven data centers, while maintaining energy security and supporting climate goals.

The Daya Bay project demonstrates that nuclear modernization is becoming a practical solution to meet rising electricity demand. Unlike solar and wind power, which are intermittent, nuclear plants provide stable, continuous power that can reliably support 24/7 operations. As electricity demand continues to grow across the region, ensuring that critical nuclear infrastructure remains safe and reliable becomes increasingly important for economic stability and energy security.