A Power Station That Doesn’t Generate Electricity — Yet Moves 120 Million kWh a Year

In Penglai, Shandong Province, there stands a power station that defies conventional definitions of energy infrastructure.

It does not generate electricity.
It does not burn coal.
It does not rely on government subsidies.

Yet every year, it processes 120 million kilowatt-hours of electricity, reduces carbon emissions by 45,600 tonnes, and generates approximately RMB 90,000 in daily revenue.

Developed by China Energy Investment Corporation (CHN Energy), the Penglai project is China’s first hybrid energy storage power station integrating four different storage technologies within a single system. In June 2025, the project officially entered commercial operation, marking a critical milestone in China’s transition from single-technology pilots to large-scale, integrated energy storage deployment.

For participating technology providers such as BOCO Electronics, the project represents a real-world validation of high-density, high-efficiency power conversion under the most demanding grid conditions.

From Thermal Backup to Storage-Based Grid Balancing

Shandong is one of China’s largest renewable energy provinces. By 2024, installed renewable capacity had surpassed coal-fired power generation for the first time, driven by rapid expansion of solar and wind installations.

However, this progress also intensified a long-standing challenge: renewable curtailment.

• Solar output peaks at midday, when demand is low
• Evening demand surges after solar generation has faded
• Grid congestion prevents surplus power from being transmitted elsewhere

As a result, clean electricity is often available but cannot be effectively utilized.

The Penglai hybrid storage station was designed as a system-level response to this imbalance. Acting as a large-scale energy buffer, the station absorbs surplus power during low-demand periods and releases it during peak hours. Beyond peak shaving and valley filling, it actively participates in frequency regulation, voltage support, and grid stability services, transforming energy storage from a passive asset into an active grid control resource.

Four Storage Technologies, One Coordinated System

Unlike conventional energy storage plants that rely on a single technology, the Penglai project integrates four distinct storage technologies, each selected for its specific operational strengths:

• Flywheel energy storage delivers millisecond-level response for fast frequency regulation
• Lithium iron phosphate (LFP) batteries provide the main energy backbone with proven reliability
• Sodium-ion batteries offer improved safety and stable performance in low-temperature environments
• Vanadium redox flow batteries enable deep cycling with a lifespan exceeding 20,000 cycles

This multi-technology configuration allows the system to respond optimally across a wide range of operating scenarios—from rapid grid disturbances to long-duration energy shifting.

However, integrating such diverse technologies introduces major challenges in voltage compatibility, control stability, and real-time coordination. This is where BOCO Electronics’ Gemini 125 bidirectional buck-boost DC-DC converters play a critical role.

Enabling Multi-Technology Coordination with Gemini 125

The Gemini 125 converter series serves as a key energy routing and regulation unit within the Penglai station. Designed for complex DC-coupled energy systems, the converter enables seamless interaction between batteries, renewable sources, and DC buses.

According to project engineers, system-level reliability was the top priority:

“When multiple storage technologies operate simultaneously, both the control system and the power conversion units must remain extremely stable. BOCO Electronics’ converters stood out for their compact design, flexible interfaces, and consistent operational reliability.”

The Gemini 125 supports a wide range of demanding application scenarios:

• Multi-technology integration
  Operating across a 600–1500 V DC voltage range, the converter is compatible with lithium-ion, sodium-ion, flow batteries, and photovoltaic inputs, significantly increasing deployment flexibility.
• Space-constrained installations
  With a power density of 7.1 kW/L—roughly the size of a household microwave—the unit enables compact cabinet layouts, reducing civil engineering and installation costs.
• Efficiency-critical operation
  Built entirely with silicon carbide (SiC) power devices, the converter achieves up to 99.2% efficiency, ensuring that every kilowatt-hour of renewable energy retains maximum economic value.
• High-safety environments
  Millisecond-level short-circuit protection and a fault current I²t below 1.6 kA²s ensure stable operation even under extreme fault conditions.
• Scalable system architecture
  Supporting up to 40 units in parallel and multiple operating modes—including constant voltage, constant current, and MPPT—the system allows fast expansion and flexible dispatch without major redesign.

From Cost Center to Revenue Engine

Historically, energy storage has often been perceived as a capital-intensive investment with long payback periods. The Penglai project challenges that perception with concrete performance data:

• Daily revenue exceeding RMB 90,000, derived from peak–valley arbitrage, frequency regulation, and capacity leasing
• Annual energy throughput of 120 million kWh, equivalent to powering approximately 15 million air conditioners for a full day
• Annual carbon reduction of 45,600 tonnes, comparable to planting roughly 25,000 mature trees

These results are not driven by subsidies, but by system efficiency, compatibility, and dispatch flexibility—areas where power conversion performance directly influences commercial returns.

Engineering for Real-World Energy Systems

The success of the Penglai hybrid storage station illustrates a broader shift in the energy industry: from technology demonstrations toward commercially viable, system-integrated solutions.

As China moves from thermal-dominated grid stabilization to storage-driven dispatch, the role of high-performance power conversion becomes increasingly central. BOCO Electronics continues to focus on engineering fundamentals—semiconductor selection, topology optimization, and system-level integration—to support this transition.

By enabling renewable energy to be stored reliably, released efficiently, and monetized effectively, BOCO Electronics aims to provide the “power conversion engine” behind the next generation of large-scale energy storage systems.