Air-Core Shunt Reactor Market Size, Grid Modernization Trends & Forecast 2035

Air-Core Shunt Reactor Market Size & Forecast 2035

The global air-core shunt reactor market was valued at US$914.83 million in 2025 and is projected to reach US$1.87 billion by 2035, growing at a CAGR of 7.4% during 2026-2035. Transmission-grid expansion, extra-high-voltage networks, renewable-energy evacuation, underground cable projects and substation modernization are increasing the requirement for inductive reactive-power compensation and voltage control.

Air-core shunt reactors absorb the capacitive reactive power produced by lightly loaded transmission lines and high-voltage cables. The dry-type architecture removes insulating oil and the associated oil-containment and fire-protection systems while providing linear inductance, low maintenance requirements, and outdoor installation capability. Current commercial designs reach transmission-level ratings: Trench Group lists dry air-core shunt reactors up to 550 kV and 250 MVAr.

The investment environment remains favorable. More than 2,500 GW of renewable generation, storage and large-load projects were waiting in grid-connection queues worldwide in 2025, while the IEA estimates annual grid investment must rise by roughly 50% from the current US$400 billion level by 2030. Long transmission development cycles, voltage uprating, and renewable-grid connections directly support demand for reactive-power equipment.

Market Highlights

• 2025 Market Size: US$914.83 Million
• 2035 Market Size: US$1.87 Billion
• CAGR, 2026-2035: 7.4%
• Leading Product: Fixed Shunt Reactors
• Fixed Reactor Share: 58% in 2025
• Leading Phase Configuration: Three-Phase Systems
• Leading End Use: Electric Utilities
• Leading Region: Asia-Pacific
• Asia-Pacific Market: More than US$400 million in 2025
• Core Applications: EHV transmission, underground cables, renewable evacuation, bus compensation and transformer-tertiary compensation
• Key Technology Themes: dry-type insulation, variable compensation, modular reactor stacks, lower noise, reduced losses and high-voltage air-core designs. 

Air-Core Shunt Reactors Solve the Light-Load Overvoltage Problem

Long high-voltage transmission lines and underground cables behave capacitively. When power transfer is low, the capacitive reactive power generated by the network can raise system voltage beyond its desired operating range.

A shunt reactor introduces inductive reactive power to counter that effect.

The reactor can be connected directly to a transmission line, to a substation bus or to the tertiary winding of a large transformer. Trench Group identifies long lightly loaded lines and underground cables as core high-voltage shunt-reactor applications.

The requirement becomes more significant as transmission networks operate across wider power-flow ranges. A corridor that carries heavy renewable output during one part of the day can operate at much lower loading during another. Voltage-control equipment therefore needs to maintain acceptable conditions across both operating states.

Grid expansion increases the number of locations where this compensation is required. The IEA reports that transmission investment reached US$140 billion in 2023 and needs to exceed US$200 billion per year by the mid-2030s under current policy settings.

Key Takeaways

• The market is projected to increase from US$914.83 million in 2025 to US$1.87 billion by 2035, with transmission expansion and renewable-grid integration providing the largest demand base.
• Fixed shunt reactors remain the largest product category, holding 58% of the market in 2024, because they provide a comparatively simple and cost-efficient solution where compensation requirements are predictable.
• Variable shunt reactors are growing faster as power flows become less predictable. Current air-core variable shunt reactor research places the segment at US$388.2 million in 2025 and forecasts an 8.1% CAGR through 2035.
• Dry-type air-core technology is moving deeper into EHV transmission. Trench lists commercial shunt designs up to 550 kV/250 MVAr and has successfully type-tested a 500 kV, 200 MVAr dry-type reactor.
• Underground cable deployment creates a direct compensation requirement. Swissgrid's Gotthard project includes an 18 km, 220 kV underground cable, and its January 2026 procurement specified a 230 kV, 40 MVA dry-type air-core shunt reactor to compensate cable reactive power.
• Asia-Pacific carries the largest current revenue pool. The region exceeded US$400 million in 2025, supported by high-voltage network construction across China, India and other major electricity markets.
• Manufacturing capacity is expanding alongside transmission demand. Trench Austria opened a new production line in 2025 as part of an investment program designed to double production capacity by 2026. 

Dry-Type Air-Core Reactors Gain Ground Against Oil-Immersed Designs

Air-core reactors do not use a ferromagnetic core or liquid insulation around the winding.

This produces several practical differences.

The absence of oil removes the risk of oil leakage and eliminates requirements for oil pits, collection systems and reactor-specific firewalls. Trench also cites reduced foundation requirements, lower maintenance and simpler protection architecture among the benefits of its dry-type high-voltage design.

Air-core construction also avoids magnetic-core saturation. Inductance remains linear over a wide operating range, which is useful during abnormal voltage and current conditions.

Maintenance requirements are lower because there is no insulating oil to sample, no dissolved-gas analysis and no oil-temperature or level instrumentation associated with conventional liquid-filled equipment.

The trade-off is physical layout.

Dry air-core coils create external magnetic fields, so substation design needs sufficient electromagnetic clearance from steel structures, fences, cable systems and other conductive equipment. Current market analysis identifies electromagnetic-interference considerations and initial installation cost among the constraints on air-core adoption.

The market will therefore continue to support both technologies. Air-core designs gain where low maintenance, fire safety and environmental simplicity carry greater value, while liquid-filled reactors retain strong positions where compact footprint and very high ratings determine the project architecture.

Fixed Shunt Reactors Hold 58% of the Market

Fixed reactors remain the dominant product because many transmission applications have a well-defined compensation requirement.

A fixed reactor provides one inductive rating whenever it is energized. The architecture is relatively straightforward, has no regulation mechanism and is suited to long lines, cable circuits or busbars where the required reactive compensation does not vary dramatically.

Fixed designs held 58% of global air-core shunt reactor revenue in 2024.

Their strongest applications include:

long EHV overhead lines, predictable underground cable circuits, transformer-tertiary compensation and fixed substation bus compensation.

The economic case is strongest where a single reactor rating can keep voltage within the required range across most operating scenarios.

Variable Shunt Reactors Grow Faster as Grid Conditions Become Less Predictable

Variable compensation becomes more valuable when system conditions change substantially through the day.

Solar output can decline rapidly in the evening. Wind output can change over shorter periods. Transmission lines can move from high renewable transfer to light loading. Conventional generation can also change dispatch as energy markets respond to price and system conditions.

Variable shunt reactors adjust the amount of inductive reactive power rather than supplying one fixed compensation level.

The air-core variable shunt reactor market was valued at US$388.2 million in 2025 and is forecast to reach US$855.2 million by 2035, growing at 8.1% during 2026-2035.

Siemens Energy's wider shunt-reactor portfolio describes the same system requirement: fixed reactors provide economical compensation under defined operating conditions, while variable designs track changing grid loading to avoid excessive or insufficient reactive compensation.

Air-core specialists are also developing variable high-voltage designs. Coil Innovation states that its HV air-core shunts can be engineered with fixed or variable inductance.

Variable reactors will therefore capture a larger share of new projects in renewable-dense networks, even while fixed reactors retain the larger installed base.

Three-Phase Applications Remain the Largest System Configuration

Three-phase applications hold the leading share because transmission and bulk-power networks operate primarily as three-phase systems.

A current market benchmark forecasts the three-phase category to exceed US$940 million by 2034.

Physical construction can still vary considerably.

A three-phase reactor bank may be formed from separate single-phase air-core coils rather than one integrated three-phase enclosure. At high voltage, separate phases can simplify insulation, transport, installation, protection and replacement.

Modular stacking is becoming more important at higher ratings. Trench states that its shunt reactors can be constructed as two columns connected in series, reducing transportation and installation complexity.

Phase architecture is therefore determined by system voltage, required MVAr rating, substation layout, transport restrictions and redundancy strategy rather than by one universal design.

High-Voltage Air-Core Technology Has Crossed the 500 kV Threshold

Historically, dry-type air-core reactors were more closely associated with medium voltage, transformer tertiaries and specialized power-quality applications.

That voltage boundary has moved significantly upward.

Trench's commercial air-core shunt portfolio now covers installations up to 550 kV and 250 MVAr.

The company has also type-tested a 500 kV, 200 MVAr dry-type air-core shunt reactor, following earlier deployment of 420 kV units.

Coil Innovation likewise states that its air-core shunt reactors support system voltages up to 550 kV. Its earlier 420 kV German project used dry-type high-voltage reactors to compensate underground transmission cables.

This development expands the addressable market beyond tertiary-connected compensation and into direct EHV line and bus applications.

Underground High-Voltage Cables Create a Strong Air-Core Application

Underground and submarine AC cables have high capacitance. Long cable sections can therefore produce substantial charging reactive power even when little active power is being transmitted.

Shunt reactors absorb that charging power.

Swissgrid provides a current example. The utility is installing an 18 km, 220 kV underground line through the Gotthard Road Tunnel, replacing 23 km of overhead line. The cable is scheduled to enter service in 2030.

In January 2026, the project's equipment procurement specified a 230 kV, 40 MVA, 50 Hz dry-type air-core shunt reactor specifically to provide partial compensation for the reactive power generated by the cable.

Cable projects are particularly relevant to Europe because permitting, urban constraints and landscape protection are pushing selected EHV sections underground.

Every cable does not require the same degree of compensation. Reactor rating depends on cable length, voltage, operating profile and surrounding network conditions. Long cable routes nevertheless create one of the clearest engineering cases for shunt compensation.

Renewable Energy Changes the Daily Reactive-Power Profile

Renewable generation affects the reactor market through both transmission construction and changing utilization of existing lines.

Large solar and wind zones are frequently located far from demand centers. New EHV corridors are therefore needed to move power from renewable-resource regions into urban and industrial loads.

The same line can operate at high transfer during favorable generation conditions and light transfer at other times. Lower loading increases the relative impact of line capacitance and strengthens the requirement for voltage control.

The IEA expects solar PV and wind to increase from 17% of global electricity generation today to 27% by 2030. Renewables are forecast to add close to 1,000 TWh of generation annually through 2030.

India illustrates the resulting equipment cycle. GE Vernova secured an order in May 2025 to supply more than 70 units of 765 kV transformers and shunt reactors to POWERGRID for renewable-energy transmission corridors, with deliveries beginning in 2026. The order covers the broader shunt-reactor category and demonstrates the scale of reactive-power equipment being procured for EHV renewable evacuation.

The Khavda renewable-energy transmission project provides another example, with 765 kV shunt reactors included alongside GIS and power transformers to maintain voltage stability.

Utility Networks Form the Core End-Use Market

Electric utilities represent the central revenue base for air-core shunt reactors.

The equipment is installed primarily in transmission substations, at line terminals, on high-voltage buses, near cable transition points and on transformer tertiary systems.

The North American market provides a direct example of switchable air-core deployment. The U.S. Department of Energy documents a Bonneville Power Administration project at Jones Canyon Substation in Oregon involving a 230 kV switchable air-core shunt reactor bank for voltage stabilization and transmission reliability.

Industrial applications remain relevant where large private networks contain long high-voltage feeders, generation facilities, arc furnaces, mines or other electrical systems with specific reactive-power requirements.

Electrical testing laboratories and equipment manufacturers also use specialized air-core reactors, but these applications represent a smaller revenue base than utility transmission.

Switching Performance Is a Critical Engineering Requirement

A high-voltage reactor is not simply connected to a line and left permanently energized.

Switchable reactors can operate repeatedly as network voltage and load conditions change.

Opening and closing an inductive circuit can create transient voltages and currents. Circuit breakers, surge arresters, insulation coordination, grounding and control strategy therefore form part of the reactor installation.

IEEE's current technical overview identifies controlled switching and metal-oxide surge arresters as major methods for reducing reactor-switching overvoltages.

Protection becomes particularly important as variable generation causes more frequent switching.

The reactor, breaker and protection scheme need to be engineered as one electrical system. Excessive emphasis on the reactor's MVAr rating without switching studies can leave the substation exposed to unnecessary transient stress.

Low Noise Is Becoming More Important Near Populated Substations

Air-core reactors produce electromagnetic forces and acoustic noise.

Noise requirements become more stringent where EHV substations sit close to residential or commercial development.

Trench states that low noise is maintained across the service life of its air-core shunt reactor designs and offers specialized noise-control solutions across its reactor portfolio.

Mechanical rigidity is also important. Electromagnetic forces can act on windings during normal and abnormal operating conditions, requiring strong winding encapsulation and structural support.

Modern air-core designs use aluminium or copper conductors with fiberglass and resin structures to maintain winding position, insulation and mechanical strength throughout the reactor's operating life.

Asia-Pacific Leads the Global Market

Asia-Pacific exceeded US$400 million in air-core shunt reactor revenue in 2025, representing the largest regional demand pool in current market analysis.

China and India account for much of the region's structural opportunity.

Both countries are adding EHV and UHV corridors to connect renewable-resource regions, generation centers and major demand zones. Higher transmission voltages increase the importance of voltage-profile management and reactive compensation.

China also contains a large domestic high-voltage reactor manufacturing base. Tianjin Jingwei Zhengneng Electrical Energy Equipment states that it developed a 500 kV dry-type air-core shunt reactor and supplied units for a Brazilian UHV-grid expansion project, illustrating the international reach of Chinese air-core technology.

India's EHV investment cycle is equally significant. GE Vernova's current POWERGRID program includes 765 kV transformers and shunt reactors for renewable corridors across Rajasthan, Gujarat, Karnataka, Tamil Nadu and Andhra Pradesh, with deliveries running from 2026 through 2027.

Europe Is a High-Voltage Cable and Grid-Modernization Market

Europe combines mature transmission assets with offshore wind, underground cable projects and cross-border grid reinforcement.

Air-core technology has gained traction in projects where fire safety, reduced maintenance and elimination of insulating oil justify a dry-type architecture.

Coil Innovation's 420 kV technology was selected for German cable-compensation applications, with each three-phase system providing 120 MVAr of compensation.

The Swiss Gotthard project provides a newer demand signal. The 18 km 220 kV cable will require dedicated inductive compensation, and Swissgrid's 2026 tender specifically called for dry-type air-core technology.

European undergrounding and cable projects therefore create a distinct air-core opportunity beyond conventional overhead-line compensation.

North America Remains a Large Replacement and Grid-Expansion Market

The U.S. air-core shunt reactor market was valued at US$107.5 million in 2024, up from US$94.1 million in 2022.

Demand is connected with renewable interconnection, transmission reinforcement and voltage management across large regional networks.

The BPA Jones Canyon installation shows the practical role of switchable air-core reactors in areas containing substantial wind generation and long transmission corridors. The 230 kV reactor bank was specified to stabilize voltage and maintain system reliability.

Grid-connection pressure is adding further investment requirements. The IEA reports that transmission projects can require five to fifteen years to plan and construct, while renewable plants and data centers can be developed far more quickly.

This timing gap strengthens demand for both new transmission infrastructure and targeted voltage-control upgrades on existing networks.

Middle East Grid Expansion Creates a Larger Reactive-Power Equipment Base

The Middle East is expanding transmission networks alongside utility-scale solar, wind, storage and industrial development.

Saudi Energy reported that its transmission network exceeded 104,600 circuit-km at the end of 2025, increasing 4.9% during the year, while 12.3 GW of renewable generation had been connected to the grid.

Larger renewable projects will add additional transmission requirements. Saudi Arabia signed PPAs for 15 GW of new solar and wind projects in July 2025, with commissioning planned across 2027 and 2028.

The resulting requirement for new high-voltage substations, long transmission corridors, and voltage management creates a wider addressable market for fixed and controllable reactive-power equipment.

Latin America Combines Long Transmission Distances With Renewable Generation

Latin American electricity systems frequently move large quantities of hydropower and renewable electricity over long distances.

Brazil has already adopted high-voltage dry air-core technology. Tianjin Jingwei Zhengneng states that its 500 kV dry-type air-core shunt reactors were supplied in volume for a Brazilian UHV transmission expansion project in 2023.

Alternative liquid-filled shunt technologies remain strong competitors. In May 2026, Hitachi Energy delivered its first 460 kV natural-ester-filled shunt reactor to ISA Energia Brasil's Bauru substation. Four single-phase units are rated at 66.67 MVAr each.

Brazil therefore demonstrates the market's technology competition clearly: dry air-core systems offer oil-free operation and reduced maintenance, while ester-filled and conventional liquid reactors continue to compete where compact high-voltage designs are preferred.

Competitive Landscape

Trench Group

Trench has one of the clearest specialized positions in dry-type high-voltage air-core technology.

Its current shunt reactor portfolio reaches 550 kV and 250 MVAr and is designed for long lightly loaded transmission lines, underground cables, transformer tertiaries and direct HV-bus connections.

The company has also type-tested a 500 kV, 200 MVAr dry-type shunt reactor and opened a new Austrian manufacturing line in 2025 as part of a program to double production by 2026.

Trench's competitive position is built around high-voltage capability, modular installation, oil-free construction and low-maintenance operation.

Coil Innovation

Coil Innovation specializes in air-core dry-type reactor technology and supplies high-voltage shunt products up to 550 kV.

Its product architecture covers fixed and variable shunt functions as well as TCR, STATCOM, filter and other power-quality reactor applications.

The company's 420 kV German underground-cable project established a reference for direct EHV air-core compensation, with two three-phase systems installed at each transition station.

GE Vernova

GE Vernova maintains dry-type air-core reactor engineering capability alongside a broader portfolio of oil-filled reactors and grid equipment.

Its current technical resources cover dry air-core shunt reactors for transmission-voltage management, including switching, grounding, and protection considerations.

GE Vernova also participates in large EHV shunt-reactor procurement programs. The 2025 POWERGRID award covers more than 70 transformers and shunt reactors for renewable corridors, with equipment deliveries starting in 2026.

Siemens Energy

Siemens Energy competes across fixed and variable shunt reactor systems.

Its current portfolio emphasizes variable compensation where power flows change frequently, with low-noise, low-loss, and extended regulation options available for transmission applications.

Variable-reactor expertise is increasingly relevant as renewable generation raises the range of operating conditions experienced by high-voltage lines.

Hitachi Energy

Hitachi Energy has a strong position across high-voltage shunt reactors, transmission transformers and grid-integration equipment.

Its current portfolio activity includes 245 kV and 420 kV variable shunt reactor technology development in India and large reactor programs in European and Asian transmission networks.

Its liquid-filled shunt portfolio also creates direct technology competition with dry air-core designs at high voltage.

Tianjin Jingwei Zhengneng / BPEG

Chinese manufacturers are strengthening high-voltage air-core capability.

Tianjin Jingwei Zhengneng Electrical Energy Equipment states that its portfolio includes 500 kV dry-type air-core shunt reactors as well as ±1,100 kV air-core smoothing reactors for HVDC applications.

The company's Brazilian 500 kV shunt references demonstrate increasing export competition in a market historically dominated by European, Japanese, and North American high-voltage equipment companies.

Recent Developments

August 2026 - Gotthard Air-Core Reactor Procurement Advances

Swissgrid's Gotthard procurement covers a 230 kV, 40 MVA dry-type air-core shunt reactor associated with the new 220 kV cable through the Gotthard Road Tunnel. The cable project is scheduled to enter operation in 2030.

2026 - Trench Expands High-Voltage Air-Core Positioning

Trench's current high-voltage portfolio includes dry air-core shunt designs up to 550 kV/250 MVAr and applications on 765 kV transmission systems through direct or tertiary-connected compensation arrangements.

2025-2026 - Austrian Reactor Manufacturing Capacity Expands

Trench Austria opened a new manufacturing line in 2025 under an investment initiative designed to double reactor production capacity by 2026.

2025 - India Places Large EHV Shunt-Reactor Orders

POWERGRID selected GE Vernova to supply more than 70 units of 765 kV transformers and shunt reactors for renewable-transmission projects, with deliveries beginning in 2026 and continuing through 2027.

2025 - Renewable Transmission Remains a Major Project Driver

GE Vernova was also selected for 765 kV shunt reactors, transformers and GIS equipment for India's Khavda Phase-IV Part C renewable transmission project.

Specification and Procurement Criteria

Reactive Power Rating

MVAr requirements should be established through load-flow and voltage studies rather than selected from transmission voltage alone.

The calculation needs to consider light-load conditions, cable charging, renewable operating profiles, switching configuration and acceptable steady-state voltage.

System Voltage

Direct-connected high-voltage designs require insulation systems suited to full transmission voltage.

Commercial dry air-core designs now reach 500-550 kV class applications, materially expanding the technology's potential beyond transformer-tertiary installations.

Fixed or Variable Compensation

A fixed reactor is well suited to predictable compensation requirements.

Variable designs provide greater value where renewable output, network topology or daily loading produces significant swings in reactive power.

Magnetic Clearance

The external magnetic field of an air-core reactor needs to be incorporated into substation layout.

Nearby steel structures, fencing, cable routes and electrical equipment require appropriate separation or engineering controls.

Acoustic Performance

Noise limits can determine coil geometry, structural design and the need for additional acoustic treatment where substations are close to populated areas.

Switching and Protection

Circuit-breaker duty, point-on-wave switching, surge arresters, grounding and protection need to be evaluated alongside the reactor itself because switching an inductive load can create transient overvoltages.

Maintenance Architecture

Dry air-core systems avoid oil testing, gas analysis, and liquid-containment systems. Periodic inspection and cleaning remain necessary, particularly for outdoor windings exposed to pollution, salt or dust.

Transport and Installation

Large high-voltage coils need to fit transport envelopes and available lifting equipment.

Modular reactor columns can simplify shipment and reduce the cost of replacing individual sections following a failure.

Air-Core Shunt Reactor Market Scope