High-voltage direct current (HVDC) and high-voltage alternating current (HVAC) transmission technologies are attracting major investment as utilities expand electricity networks to support renewable energy, AI data centres and industrial electrification.
HVDC is increasingly used for long-distance electricity transmission, offshore wind connections and high-capacity renewable energy corridors, while HVAC remains the backbone of regional electricity networks.
Companies including Hitachi Energy, Siemens Energy, GE Vernova, Mitsubishi Electric, Prysmian, NKT, Nexans and BHEL are benefiting from demand for converters, transformers, cables, substations and transmission infrastructure.
The choice between HVDC and HVAC depends on project cost, transmission distance, power losses, capacity and operating requirements.
The break-even distances and losses are indicative. Actual economics depend on voltage, capacity, terrain, equipment configuration and operating conditions.
HVDC Transmission Costs Compared with HVAC
HVAC transmission generally requires lower investment in terminal equipment because it does not need AC-to-DC and DC-to-AC converter stations.
HVDC requires expensive converter technology but can reduce conductor requirements, transmission losses and right-of-way costs over sufficiently long distances.
Indicative Indian planning estimates place the cost of a ±800 kV HVDC overhead line at approximately ₹3.42 crore per kilometre.
A 765 kV HVAC double-circuit line has an indicative cost of approximately ₹5.69 crore per kilometre.
These figures cover different line configurations and do not represent complete turnkey project costs.
HVDC converter stations, land acquisition, engineering, financing and other infrastructure expenses must be included before comparing total project investment.
For overhead transmission, HVDC commonly becomes economically competitive over distances of approximately 300–800 kilometres.
For submarine and underground cables, the crossover may occur around 50–100 kilometres because long AC cables face charging-current constraints.
HVDC Transmission Losses Can Be Lower Over Long Distances
HVDC technology avoids reactive-power transmission requirements associated with AC systems and reduces some long-distance electricity losses.
The US Energy Information Administration’s HVDC transmission analysis reports indicative line losses of approximately 3.5 percent per 1,000 kilometres for HVDC, compared with 6.7 percent for comparable HVAC lines.
However, HVDC converter stations introduce additional losses, commonly around 0.6–1 percent per terminal.
Consider a 1,000 MW transmission link operating at 70 percent utilisation.
Annual electricity transfer before losses would reach approximately 6.13 TWh.
A one-percentage-point reduction in transmission losses would preserve approximately 61.3 GWh annually.
At an assumed electricity value of ₹5 per kWh, the additional delivered electricity would be worth approximately ₹30.7 crore annually.
Actual savings depend on utilisation, system design, electricity prices and operating availability.
China Develops 8 GW HVDC Transmission Corridors
China is among the largest investors in ultra-high-voltage direct-current transmission infrastructure.
The Hami–Chongqing UHVDC project entered operation in June 2025.
The ±800 kV transmission corridor extends approximately 2,260 kilometres and has a rated capacity of 8 GW.
It is expected to deliver more than 36 billion kWh of electricity annually.
More than 70 percent of its associated generation capacity comes from renewable energy resources.
Another major development, the Ningxia–Hunan UHVDC project, entered operation in 2025.
The 1,616-kilometre corridor has a transmission capacity of 8 GW and is expected to transport approximately 40 billion kWh annually.
These projects demonstrate how HVDC can connect renewable-rich regions with distant electricity demand centres.
India Bhadla–Fatehpur HVDC Project: 6 GW Transmission Capacity
Adani Energy Solutions is developing the Bhadla–Fatehpur HVDC transmission project to support renewable electricity evacuation from Rajasthan.
The ±800 kV transmission corridor will provide approximately 6,000 MW of transfer capacity over a distance of around 950 kilometres.
Commissioning is targeted for 2029.
Adani Energy Solutions secured long-term financing from Japanese banks in February 2026.
Hitachi Energy and BHEL are involved in the converter-terminal package.
The Adani Energy Solutions project financing announcement provides information on the transmission corridor and financing arrangements.
The project illustrates India’s growing investment in long-distance renewable energy transmission.
GE Vernova Selected for 6 GW Rajasthan HVDC Corridor
GE Vernova was selected by Power Grid Corporation of India to deliver equipment for a major 6 GW HVDC transmission corridor.
The 800 kV project will connect renewable energy resources in Barmer, Rajasthan, with South Kalamb.
The project is designed to strengthen long-distance electricity transmission and support renewable energy integration.
For GE Vernova, the development adds to opportunities in HVDC converters, grid control technologies and high-voltage electrical equipment.
UK Eastern Green Link 3: Nearly £3 Billion in Contracts
The United Kingdom is expanding offshore HVDC transmission infrastructure to move electricity between generation regions and major demand centres.
Eastern Green Link 3 is a planned 690-kilometre transmission corridor, including approximately 580 kilometres of subsea cable.
National Grid signed contracts worth nearly £3 billion in March 2026.
Hitachi Energy will supply converter stations, while NKT will deliver cable systems.
Construction is expected to begin in 2028, subject to approvals, with energisation targeted for 2033.
The National Grid Eastern Green Link project announcement provides details of the contracts and project schedule.
The contracts represent awarded work rather than completed transmission capacity.
Major HVDC and HVAC Equipment Vendors
Several global companies are positioned to benefit from electricity transmission investment.
Hitachi Energy: Supplies HVDC converter systems, transformers, substations and grid automation technologies.
Siemens Energy: Provides HVDC systems, transformers, converter stations and transmission equipment.
GE Vernova: Supplies HVDC technology, high-voltage equipment and electricity grid management solutions.
Mitsubishi Electric: Manufactures power electronics, grid equipment and high-voltage electrical systems.
Prysmian: Supplies high-voltage submarine and underground power cables.
NKT: Manufactures high-voltage cable systems for offshore and onshore transmission projects.
Nexans: Supplies subsea and land-based high-voltage cable infrastructure.
Sumitomo Electric: Manufactures high-voltage cable systems and related transmission products.
BHEL: Participates in HVDC converter projects and manufactures power transmission equipment.
Larsen & Toubro: Executes transmission lines, substations and electrical infrastructure projects.
KEC International: Provides transmission and distribution engineering and construction services.
Kalpataru Projects International: Develops high-voltage transmission lines and associated infrastructure.
HVAC Remains Essential for Regional Grid Expansion
Despite the growth of HVDC, HVAC remains essential for electricity distribution across interconnected regional transmission networks.
India’s 765 kV Fatehgarh II–Bhadla II and Sikar II–Aligarh transmission developments strengthened renewable electricity evacuation from Rajasthan.
HVAC is generally suitable for shorter transmission routes, regional substations and networks requiring multiple connection points.
HVDC is particularly valuable when electricity must travel long distances, cross subsea routes or move between asynchronous electricity systems.
India Renewable Curtailment Highlights Transmission Investment Needs
Ember estimates that India curtailed approximately 300 GWh of renewable electricity because of transmission constraints during the first quarter of 2026.
Around 20 GW of renewable capacity could face grid connectivity delays exceeding four months during FY2026–27.
HVDC transmission can reduce curtailment where long-distance transfer capacity is the main bottleneck.
However, local congestion may require HVAC upgrades, additional substations, battery storage or improved grid operations.
HVDC vs HVAC Investment Outlook Through 2030
Global transmission expansion is creating opportunities for converter manufacturers, cable suppliers, transformer producers and engineering contractors.
HVDC projects typically involve substantial converter investment but can deliver lower losses and improved control over long-distance electricity flows.
HVAC projects generally offer lower terminal costs and remain suitable for regional transmission and shorter connections.
Investors should compare total project capital expenditure, electricity losses, equipment delivery schedules, utilisation, maintenance and financing costs.
The most economical transmission technology is the one that delivers electricity reliably at the lowest lifetime cost, rather than simply offering the lowest initial construction expenditure.
SHAFANA FAZAL
