1. Introduction

Electricity interconnectors are transmission facilities that connect two electricity systems, such as two countries, two regional grids, or two separately operated electricity markets. They may be cross-border transmission lines, submarine cables, or other high-voltage infrastructure that enables electricity to flow between interconnected systems.

Interconnectors have become increasingly important because modern electricity systems depend on regional integration, renewable-energy trading, balancing resources, and security of supply. However, they also create complex legal questions concerning licensing, ownership, access, tariffs, congestion management, system operation, market coupling, environmental approval, security, cross-border jurisdiction, and dispute resolution.

The legal regulation of interconnectors therefore sits at the intersection of energy law, administrative law, competition law, international law, environmental law, property law and electricity-market regulation.

2. Meaning and Types of Electricity Interconnectors

An electricity interconnector can broadly be understood as infrastructure allowing electricity to move between otherwise distinct electricity systems.

Major forms include:

1. Cross-border transmission lines – overhead or underground lines crossing national borders.
2. Submarine interconnectors – underwater high-voltage cables connecting countries or islands.
3. AC interconnectors – alternating-current connections, generally suitable where connected systems are synchronised.
4. HVDC interconnectors – high-voltage direct-current systems, particularly useful for long-distance and submarine transmission.
5. Market interconnectors – transmission capacity used to facilitate electricity trading between separate electricity markets.
6. Multi-terminal or multi-country interconnectors – increasingly relevant to offshore renewable-energy development.

The legal regime may differ depending upon whether the interconnector is national, regional, or international, and whether it is treated as an ordinary transmission asset or a special cross-border infrastructure project.

3. Objectives of Interconnector Regulation

Regulation generally seeks to achieve several objectives simultaneously.

A. Security of supply

Interconnectors permit electricity to be imported when domestic generation is insufficient and allow neighbouring systems to provide emergency assistance.

B. Efficient electricity markets

Interconnection allows electricity to flow from areas of relatively lower-cost generation to areas where electricity is more expensive.

C. Integration of renewable energy

Interconnectors can enable surplus renewable electricity generated in one jurisdiction to be exported to another.

D. Competition

Cross-border connections can reduce the market power of dominant generators by increasing the number of potential sources of electricity.

E. Consumer protection

Regulators must ensure that the benefits of interconnection are not undermined by excessive transmission charges, discriminatory access or unreliable service.

F. Environmental objectives

Interconnectors may facilitate decarbonisation but can themselves have environmental impacts, particularly submarine cables, overhead lines and associated converter stations.

4. Licensing and Authorisation

A central element of interconnector regulation is governmental or regulatory authorisation.

Depending on the jurisdiction, an interconnector may require:

• transmission licences;
• construction approval;
• electricity-market approval;
• land acquisition or easements;
• environmental clearance;
• marine and coastal permissions;
• planning consent;
• grid-connection approval;
• cross-border infrastructure approval; and
• national-security clearance.

For example, a cross-border electricity line may be legally treated as both a transmission facility and an international infrastructure project.

The regulator must therefore coordinate different legal regimes.

5. Ownership and Unbundling

Interconnectors raise important questions regarding ownership.

An interconnector may be owned by:

• a transmission system operator;
• two transmission operators jointly;
• private investors;
• a consortium;
• a government-owned entity; or
• a special-purpose infrastructure company.

Modern electricity regulation often requires some degree of functional or ownership separation between transmission activities and competitive generation or supply.

The underlying principle is that the owner of an essential transmission facility should not use its control over the interconnector to discriminate against competitors.

This connects interconnector regulation with competition law and network unbundling rules.

6. Third-Party Access

One of the most important legal principles is non-discriminatory third-party access.

Where an interconnector constitutes essential transmission infrastructure, electricity traders and market participants should ordinarily have access according to transparent and objectively defined rules.

A regulatory framework may specify:

• available transmission capacity;
• allocation procedures;
• priority rules;
• congestion-management procedures;
• nomination requirements;
• balancing obligations;
• emergency restrictions; and
• access charges.

The basic legal concern is preventing the interconnector owner from reserving capacity for itself or preferred market participants without lawful justification.

7. Congestion Management

Interconnector capacity is limited. At certain times, more electricity may be seeking to cross the interconnector than the available physical capacity permits.

This creates congestion.

Legal rules therefore determine how scarce capacity is allocated.

Common mechanisms include:

• explicit auctions;
• implicit auctions;
• market coupling;
• capacity allocation platforms;
• long-term transmission rights; and
• short-term capacity markets.

The regulatory objective is generally to allocate scarce capacity transparently while preserving system security.

8. Tariff Regulation

Another major issue is determining who pays for an interconnector.

Potential approaches include:

Cost-based regulation

Charges reflect the costs of constructing, operating and maintaining the infrastructure.

Market-based pricing

Capacity is allocated through market mechanisms, with prices reflecting scarcity.

Regulated network tariffs

A regulator determines or approves the transmission tariff.

Cross-border cost allocation

Where an interconnector benefits several jurisdictions, the participating countries or regulatory authorities may establish mechanisms for allocating investment and operating costs.

This is particularly important for major submarine and offshore interconnectors.

9. Regulatory Independence

Because interconnectors can have significant economic value, regulatory independence is essential.

A regulator should be able to determine:

• access conditions;
• tariffs;
• technical standards;
• congestion arrangements;
• exemptions;
• market rules; and
• enforcement measures

without improper interference from network owners or market participants.

This principle is reflected strongly in European electricity regulation and is also relevant to electricity regulators in other jurisdictions.

10. Competition Law and Interconnectors

Interconnectors can create both pro-competitive and anti-competitive effects.

They can increase competition by connecting previously separated markets. However, control over scarce interconnector capacity can also create market power.

Competition authorities may therefore examine:

• capacity reservations;
• discriminatory access;
• refusal to provide access;
• exclusive agreements;
• abuse of dominance;
• market sharing; and
• infrastructure investment arrangements.

A particularly important legal question is whether an interconnector constitutes an essential facility.

11. Essential Facilities Doctrine

The essential-facilities principle becomes relevant where an infrastructure facility is indispensable for competitors to operate in a market and cannot reasonably be duplicated.

The leading European case is:

Bronner v Mediaprint, Case C-7/97 (1998)

The Court of Justice of the European Union established a demanding test for compulsory access to infrastructure under competition law. Refusal of access is not automatically unlawful merely because infrastructure is important.

The case is relevant by analogy to electricity interconnectors because regulators must balance:

• infrastructure owners' property and investment interests; and
• competitors' need for access.

Electricity-specific regulation may, however, impose access obligations independently of general competition law.

12. Important Electricity Case Law

A. Commission v Belgium — C-543/08

In Commission v Belgium, the CJEU considered aspects of national rules concerning electricity infrastructure and cross-border electricity arrangements.

The broader significance of EU electricity jurisprudence is that national measures affecting cross-border electricity infrastructure must comply with European internal-market principles.

This illustrates an important principle:

National control over electricity infrastructure cannot be exercised entirely independently of supranational market obligations where cross-border trade is legally protected.

B. Federutility and Others v Autorità per l'energia elettrica e il gas — C-265/08

In Federutility v AEEG (2010), the CJEU examined state intervention in energy pricing.

Although the dispute concerned gas rather than an electricity interconnector, the judgment is important for energy regulation because it established that state intervention in energy markets must satisfy principles of:

• public-interest justification;
• proportionality;
• clearly defined objectives; and
• temporal and regulatory necessity.

These principles are relevant when governments impose restrictions affecting cross-border electricity flows.

C. ENEL Produzione SpA v Autorità per l'energia elettrica e il gas — C-242/10

The CJEU examined regulatory measures affecting electricity generation and market operation.

The case illustrates the broader European principle that regulatory interventions in electricity markets must respect the structure of the internal electricity market while allowing legitimate measures for system security.

13. European Union Regulation

The European Union provides one of the most developed legal frameworks for electricity interconnectors.

Important legislation includes:

• Regulation (EU) 2019/943 on the internal market for electricity;
• Directive (EU) 2019/944 concerning common rules for the internal market for electricity; and
• Regulation (EU) 2022/869 concerning guidelines for trans-European energy infrastructure.

The EU framework addresses:

• cross-border electricity trading;
• transmission-system operation;
• congestion management;
• capacity allocation;
• network development;
• interconnector investment;
• infrastructure planning; and
• market integration.

The EU's ENTSO-E framework also plays a significant role in technical and operational coordination.

14. Cross-Border Electricity and EU Market Integration

Interconnectors are fundamental to the EU concept of an integrated electricity market.

A simplified model is:

Country A → Interconnector → Country B

If Country A has surplus low-cost electricity and Country B has a shortage, electricity can flow from A to B.

Legal market-coupling mechanisms attempt to ensure that this capacity is used efficiently rather than being allocated through discriminatory bilateral arrangements.

15. Exemptions for New Interconnectors

A significant legal issue concerns whether a newly constructed interconnector should immediately be subject to all ordinary regulated-access requirements.

Some legal regimes allow exemptions where the project:

• increases competition;
• involves significant investment risk;
• enhances security of supply;
• would not otherwise be constructed; and
• does not undermine the functioning of the electricity market.

The exemption must normally be carefully limited because excessive exemption can allow private infrastructure owners to acquire excessive market power.

16. Case Law on Cross-Border Electricity Regulation

ATEL Austria v Commission, T-159/11

The European regulatory framework has also generated litigation concerning cross-border electricity capacity and the allocation of transmission rights.

The case illustrates the legal complexity surrounding:

• cross-border capacity;
• regulatory competence;
• network access; and
• institutional decision-making.

The broader lesson is that cross-border electricity infrastructure requires clearly defined allocation of powers between national regulators and regional institutions.

17. Indian Legal Framework

India does not operate an EU-style international electricity market, but interconnector regulation is increasingly important because India's electricity system includes:

• inter-state transmission;
• regional grids;
• cross-border electricity trade;
• international connections with neighbouring countries; and
• renewable-energy integration.

The primary legislation is the Electricity Act, 2003.

Important institutions include:

• Central Electricity Regulatory Commission (CERC);
• Central Electricity Authority (CEA);
• transmission licensees;
• Grid Controller of India Limited; and
• Ministry of Power.

18. Electricity Act, 2003

The Electricity Act provides the legal foundation for transmission regulation in India.

The Act establishes licensing and regulatory mechanisms for transmission and provides powers concerning:

• inter-State transmission;
• transmission licences;
• open access;
• tariff determination;
• grid standards;
• system operation; and
• electricity trading.

The statutory framework is particularly important because electricity is a concurrent legislative subject and inter-State electricity infrastructure requires coordination between national and State institutions.

19. CERC and Inter-State Transmission

The CERC has a central role in regulating inter-State transmission.

Its functions include determining or regulating:

• transmission tariffs;
• access;
• transmission charges;
• grid-related matters;
• inter-State electricity trading; and
• disputes involving regulated entities within its statutory jurisdiction.

The legal framework therefore treats transmission infrastructure not merely as private property but as infrastructure subject to public regulatory obligations.

20. Cross-Border Electricity Trade in India

India has developed regulatory arrangements for electricity trade with neighbouring countries including:

• Bhutan;
• Nepal;
• Bangladesh; and
• Myanmar.

Cross-border electricity trade creates additional legal questions concerning:

• sovereignty;
• transmission ownership;
• commercial contracts;
• scheduling;
• grid security;
• currency and payment risks;
• dispute resolution; and
• emergency electricity flows.

CERC regulations and governmental guidelines therefore play an important role.

21. Indian Case Law

Energy Watchdog v CERC, (2017) 14 SCC 80

This is one of the most important modern Indian electricity-law decisions.

The Supreme Court considered regulatory and contractual issues arising from electricity-generation projects and Power Purchase Agreements.

The judgment is important to interconnector regulation because it demonstrates the Supreme Court's approach to:

• the Electricity Act's regulatory structure;
• contractual allocation of risk;
• regulatory jurisdiction; and
• the relationship between contractual rights and electricity regulation.

The Court recognised the importance of the statutory regulatory framework in determining disputes concerning electricity supply and generation.

PTC India Ltd. v Central Electricity Regulatory Commission, (2010) 4 SCC 603

This is a foundational Indian electricity-regulation case.

The Supreme Court examined the relationship between:

• regulations made by CERC;
• statutory powers;
• tariff determination; and
• appellate review.

The decision is highly relevant to interconnectors because cross-border and inter-State transmission requires detailed regulatory rules concerning capacity, tariffs, access and system operation.

It establishes the importance of properly exercised delegated regulatory power under the Electricity Act.

Gujarat Urja Vikas Nigam Ltd. v Essar Power Ltd., (2008) 4 SCC 755

The Supreme Court considered the statutory powers of electricity regulators in relation to electricity-sector disputes.

The case reinforces the principle that electricity commissions possess specialised regulatory authority under the Electricity Act.

This is relevant to interconnector disputes because questions regarding transmission arrangements and electricity-market obligations may fall within specialised regulatory jurisdiction rather than ordinary civil litigation.

22. Environmental Regulation

Interconnectors can have substantial environmental impacts.

Overhead lines

They may require:

• land acquisition;
• forest permissions;
• wildlife approvals; and
• environmental assessment.

Submarine cables

They can affect:

• marine ecosystems;
• fisheries;
• seabed environments;
• navigation; and
• coastal communities.

Consequently, an interconnector project may require multiple environmental and planning approvals.

23. International Law

International electricity interconnectors may implicate principles of international law concerning:

• territorial sovereignty;
• maritime boundaries;
• jurisdiction;
• transit;
• investment protection;
• environmental obligations; and
• dispute settlement.

Submarine interconnectors crossing maritime zones may additionally engage the United Nations Convention on the Law of the Sea (UNCLOS).

24. Security of Supply

Interconnectors create significant advantages during electricity emergencies.

If one country experiences:

• generation failure;
• extreme weather;
• fuel shortages; or
• unexpected demand,

electricity may be imported from a neighbouring system.

However, dependence on an interconnector can also create vulnerabilities. An interconnector may fail because of:

• technical faults;
• cyberattacks;
• physical attacks;
• storms;
• submarine cable damage; or
• deliberate disconnection.

Therefore, modern regulation increasingly treats interconnectors as critical infrastructure.

25. Cybersecurity Regulation

Digitalisation has transformed interconnector operation.

Modern interconnectors use:

• SCADA systems;
• digital protection systems;
• automated control;
• telecommunications;
• real-time market platforms; and
• remote monitoring.

Cybersecurity regulations therefore need to address:

• access controls;
• incident reporting;
• resilience;
• system redundancy;
• data security;
• supply-chain security; and
• emergency response.

Cybersecurity is increasingly part of electricity-infrastructure regulation rather than merely an IT issue.

26. Interconnectors and Renewable Energy

Interconnectors are especially important for renewable-energy integration.

For example:

Solar-rich region → Interconnector → High-demand region

or

Wind-rich country → HVDC cable → neighbouring electricity market

The legal framework must therefore coordinate:

• renewable-energy subsidies;
• transmission access;
• cross-border trading;
• grid balancing;
• guarantees of origin;
• congestion management; and
• environmental requirements.

27. Offshore Energy Hubs and Future Interconnectors

Future interconnectors may become more sophisticated.

An offshore wind farm may simultaneously function as:

• a renewable-energy generation facility;
• an interconnector;
• an electricity market interface; and
• a regional transmission hub.

This creates a new legal category sometimes described as hybrid interconnectors.

Regulators must determine:

• who owns the asset;
• whether it is treated as generation or transmission;
• how costs are allocated;
• who receives transmission revenues;
• how offshore capacity is auctioned; and
• which country has regulatory jurisdiction.

28. Dispute Resolution

Interconnector agreements can generate disputes involving:

• construction delays;
• transmission capacity;
• outages;
• payment obligations;
• congestion revenues;
• force majeure;
• technical standards;
• regulatory change; and
• termination.

Contracts may provide for:

• regulatory adjudication;
• arbitration;
• domestic courts;
• international commercial arbitration; or
• specialised regional dispute mechanisms.

The choice of forum is particularly important where the infrastructure crosses multiple jurisdictions.

29. Key Legal Principles

The legal regulation of electricity interconnectors can therefore be organised around several fundamental principles:

30. Major Legal Challenges

Future interconnector regulation faces several challenges.

1. Multiple jurisdictions

A single cable may cross several legal territories.

2. Regulatory fragmentation

Different countries may have different licensing and market rules.

3. Investment uncertainty

Large interconnectors require substantial capital and long payback periods.

4. Congestion

Limited capacity can produce significant market disputes.

5. Cybersecurity

Digitised interconnectors create new security vulnerabilities.

6. Climate change

Extreme weather can threaten transmission infrastructure.

7. Offshore development

Hybrid offshore projects challenge traditional distinctions between generation and transmission.

8. Energy sovereignty

States may seek to preserve control over strategic electricity infrastructure while simultaneously benefiting from international electricity trade.

31. Conclusion

The legal regulation of electricity interconnectors is fundamentally concerned with balancing three interests: efficient cross-border electricity exchange, protection of electricity-system security, and legitimate national/regulatory control over critical infrastructure.

The most important legal principles are open and non-discriminatory access, transparent capacity allocation, appropriate tariff regulation, independent regulatory supervision, competition protection, environmental safeguards and security of supply.

In India, the Electricity Act, 2003, CERC's regulatory framework, CEA's technical standards and governmental cross-border electricity-trade policies provide the principal legal foundations. Cases such as PTC India Ltd. v. CERC, Energy Watchdog v. CERC, and Gujarat Urja Vikas Nigam Ltd. v. Essar Power Ltd. demonstrate the Supreme Court's broader approach to specialised electricity regulation and statutory regulatory authority.

Internationally, the European Union provides a particularly developed model through its internal electricity-market legislation and cross-border transmission rules. Cases such as Bronner v Mediaprint and the CJEU's energy-market jurisprudence demonstrate how infrastructure access, competition, proportionality and regulatory intervention interact.

Ultimately, interconnectors should not be regarded merely as physical transmission lines. They are legally regulated gateways between electricity systems and markets. Their regulation determines who can use cross-border capacity, how infrastructure costs and revenues are distributed, how electricity markets interact, and how national energy security is reconciled with regional and international electricity cooperation.