From China’s record-breaking 2,071 km Xiangjiaba–Shanghai line to Europe’s 720 km North Sea Link, high-voltage direct current (HVDC) projects are redefining how electricity moves across borders and oceans. These mega-infrastructure builds enable bulk renewable integration, long-distance power transfer, and cross-border grid stability. For investors, the longest HVDC projects highlight the growing orderbooks of key suppliers such as Siemens Energy, Hitachi, Prysmian, and Nexans, where scale and technology leadership drive opportunity.
Quick Summary
- The longest HVDC overhead line is China’s Xiangjiaba–Shanghai at 2,071 km.
- The longest HVDC submarine cable is the North Sea Link (720 km, Norway–UK).
- Landmark projects: Itaipu (Brazil–Paraguay), SunZia (US), NordLink (Germany–Norway).
- Key companies: Siemens Energy (ETR: ENR), Hitachi (TYO: 6501), Prysmian (BIT: PRY), Nexans (EPA: NEX).
Why Length Matters in HVDC
The longer the transmission distance, the greater the efficiency benefits of HVDC over AC. HVDC enables:
- Low-loss transmission over >600 km overhead or >50 km subsea.
- Cross-border connections, enabling renewable integration.
- Bulk power transfer from remote generation hubs (hydro, solar, wind).
Longest HVDC Overhead Transmission Lines (2025)
| Project / Line | Capacity (MW) | Length (km) | Region | Companies Involved |
|---|---|---|---|---|
| Xiangjiaba–Shanghai | 6,400 | 2,071 | China | State Grid, ABB legacy tech |
| Itaipu HVDC | 6,300 | 800 | Brazil–Paraguay | Siemens, GE legacy systems |
| SunZia HVDC | 3,000 | ~885 | US (Southwest) | Hitachi Energy, Quanta Services |
| Ultranet (Germany) | 2,000 | 340 | Germany | Siemens Energy |
| Pugalur–Trichur | 2,000 | 165 | India | Hitachi Energy |
Longest HVDC Submarine Cables (2025)
| Interconnector | Capacity (MW) | Length (km) | Region | Companies Involved |
|---|---|---|---|---|
| North Sea Link | 1,400 | 720 | Norway–UK | Prysmian, Siemens Energy |
| NordLink | 1,400 | 623 | Norway–Germany | Nexans, Hitachi/ABB |
| Greenlink | 500 | 190 | UK–Ireland | Nexans, Siemens Energy |
| IFA2 | 1,000 | 200 | UK–France | Nexans, GE Vernova |
| ADNOC Offshore HVDC | 3,200 | 140 | UAE | Hitachi Energy, KEPCO |
Investor Perspective
- Scale drives opportunity: Long projects generate multi-billion-euro orderbooks.
- Cables are bottleneck: Submarine cable production is capacity-constrained, benefiting Prysmian, Nexans, and NKT.
- Technology lock-in: Hitachi and Siemens dominate converter systems for ultra-long lines.
- Regional policies matter: China’s UHVDC lines are state-driven, while Europe/US rely on regulated utilities and interconnectors.
FAQ
Q: What is the longest HVDC line in the world?
China’s Xiangjiaba–Shanghai line at 2,071 km is the world’s longest overhead HVDC line.
Q: What is the longest HVDC submarine cable?
The North Sea Link between Norway and the UK, at 720 km, is the world’s longest subsea HVDC interconnector.
Q: Why are HVDC lines longer than AC lines?
HVDC experiences lower losses and can transmit more power over long distances without stability issues.
Q: Which companies benefit from the longest HVDC projects?
Converter suppliers like Hitachi Energy and Siemens Energy, and cable makers Prysmian, Nexans, and NKT, are the main listed beneficiaries.