ACDC Trends

ACDC Trends in China

The high-voltage transmission sector, particularly High-Voltage Direct Current (HVDC) and High-Voltage Alternating Current (HVAC) systems, is undergoing a significant transformation globally. This evolution is driven by the escalating demand for efficient long-distance power transmission and the massive integration of renewable energy sources. This report summarizes the recent developments and future prospects, highlighting technological breakthroughs and market trends in this critical field.

China has established the world's largest and most technologically advanced ultra-long-distance transmission network. By the end of 2025, China had put into operation 45 ultra-high-voltage (UHV) projects, comprising a robust infrastructure of 1 ±1100 kV line, 23 ±800 kV DC lines, and 21 1000 kV AC lines. The "West-to-East Power Transmission" capacity witnessed a remarkable 25% enhancement during the "14th Five-Year Plan" period, rising from 270 GW to approximately 340 GW. The HVAC network, acting as a supportive "highway" allowing flexible access, has also been strengthened, with its line length growing from 14,000 kilometers to 20,000 kilometers. http://kpzg.people.com.cn/BIG5/n1/2025/1023/c404214-40587398.html

HVDC corridors are pivotal for China's energy transition. In 2024, cross-regional UHV DC channels transmitted about 420 billion kilowatt-hours of clean energy, accounting for nearly 60% of the total electricity delivered via these routes. This represents a 70% increase compared to the end of the "13th Five-Year Plan" period. Projects like the Ningxia-Hunan ±800 kV UHV DC project, which is dedicated to delivering power from desert-based wind and photovoltaic bases, exemplify this shift, with over 50% of its transmitted electricity coming from renewables.

Recent years have seen significant innovations enhancing the performance and reliability of HVDC systems.

·      VSC-HVDC and Flexible Topologies: The commissioning of the Southeastern Tibet - Guangdong-Hong Kong-Macao Greater Bay Area ±800 kV UHV DC project marks a milestone. As the first project to adopt a four-terminal topology, it represents the most powerful flexible DC transmission project globally. http://www.cpecc.ceec.net.cn/art/2025/11/12/art_29041_2522449.html

·       Core Component Localization: Breaking foreign monopolies in critical components is a major achievement. The Longdong-Shandong ±800 kV UHV DC project successfully applied domestic on-load tap-changers (OLTC) for converter transformers and a DC control and protection system based on domestically produced chips (http://chinalxnet.com/index/news/detail.html?id=493228). This enhances supply chain security and technological autonomy.

·       High-Altitude Construction: Projects like the Chuanyu 1000 kV HVAC AC and Jinshang-Hubei UHV DC have pioneered construction in areas with altitudes exceeding 3,000 meters, providing valuable data and methodologies for future projects in challenging terrains. http://kpzg.people.com.cn/BIG5/n1/2025/1023/c404214-40587398.html

Market Trends and Future Prospects

·    VSC-HVDC Growth: Voltage Source Converter (VSC)-based HVDC technology is gaining traction due to its superior performance in integrating renewable sources, especially offshore wind farms. Continuous advancements in power electronics, such as Silicon Carbide (SiC) semiconductors, are further boosting its efficiency and cost-effectiveness. https://www.theinsightpartners.com/zh-CN/reports/hvdc-transmission-market

·    Data Center Power Revolution: The booming AI industry is reshaping power architecture in data centers. Traditional Uninterruptible Power Supplies (UPS) are being phased out in favor of 800V HVDC systems, which offer higher efficiency, better reliability, and a smaller footprint. The ultimate roadmap points towards Solid-State Transformers (SST) and medium-voltage rectifiers. https://www.9fzt.com/9fztgw_1_top/2df4221d5b65e63533d6d781ab766901.html; https://dxpress.gelonghui.com/p/3047319

·       Key Drivers: The primary growth engines are the increasing need for efficient long-distance transmission and the large-scale integration of renewable energy into the grid. https://www.theinsightpartners.com/zh-CN/reports/hvdc-transmission-market

·       Market Outlook: The global HVDC transmission market is projected to grow at a CAGR of 4.2% from 2025 to 2031. Regionally, the United States and China are expected to be the core markets for the commercialization of 800V HVDC technology, driven by massive investments in AI infrastructure and projects like "East Data West Computing". Opportunities are particularly prominent in subsea transmission for offshore wind and widespread grid modernization initiatives.