1. Introduction

Interconnection investment approval and regulatory consent refers to the legal and regulatory process through which an electricity interconnector, transmission link, or major grid-connection project receives permission to be planned, financed, constructed, connected, operated and, where relevant, recovered through regulated tariffs.

An interconnection may connect:

two transmission systems;

two countries or bidding zones;

a generator to the transmission or distribution network;

offshore renewable generation to the mainland grid;

two regional electricity networks; or

a new transmission asset to an existing network.

Because such projects involve substantial capital expenditure, network security, land or marine rights, environmental effects, market access and potentially cross-border electricity flows, investment approval and physical/regulatory consent are normally separate but interconnected legal requirements.

The European Union framework expressly treats cross-border interconnection as an element of an integrated electricity market and seeks fair rules for cross-border exchanges and allocation of interconnection capacity. (EUR-Lex)

2. Meaning of Investment Approval

Investment approval is the regulatory decision that a proposed interconnection project is sufficiently justified to proceed from a financial and system-planning perspective.

A regulator or system-planning authority may examine:

System need – whether additional interconnection capacity is required.

Security of supply – whether the project improves system reliability.

Congestion reduction – whether existing transmission constraints will be relieved.

Economic efficiency – whether expected benefits justify costs.

Renewable integration – whether the project facilitates renewable generation.

Cross-border trade – whether it increases electricity-market integration.

Consumer impact – whether costs ultimately imposed on consumers are justified.

Alternative solutions – whether reinforcement, storage, demand response or other measures could achieve the same objective more efficiently.

Investment approval therefore differs from a simple construction permit. It addresses the regulatory justification for committing capital to the network.

3. Meaning of Regulatory Consent

Regulatory consent concerns the legal permissions necessary for the project to be implemented.

Depending on the jurisdiction, these can include:

transmission or interconnector licences;

construction/development consent;

planning permission;

environmental approval;

marine consent for submarine cables;

land acquisition or wayleaves;

grid-connection approval;

tariff or cost-recovery approval;

cross-border regulatory approval;

market-access approval; and

exemptions from regulated third-party access rules.

The UK illustrates this separation. Energy infrastructure projects can require development consent under the Planning Act 2008 framework, while the Electricity Act 1989 provides important electricity-specific consent mechanisms. (GOV.UK)

4. Legal Framework for Interconnection Investment

A. European Union

EU electricity law provides one of the most developed legal frameworks for interconnection.

Regulation (EU) 2019/943 establishes principles for integrated electricity markets and specifically addresses cross-border exchanges and the allocation of available interconnection capacity. (EUR-Lex)

The framework seeks to remove barriers to cross-border electricity flows and requires electricity-market arrangements to facilitate market integration. (EUR-Lex)

A major interconnector may therefore have to satisfy both:

national regulatory requirements + EU cross-border electricity requirements.

B. United Kingdom

In Great Britain, interconnectors are regulated through licensing, electricity-market regulation and planning/development arrangements.

Ofgem regulates electricity interconnectors and publishes consultations and regulatory materials concerning their licensing and regulatory treatment. (Ofgem)

The UK is also developing a more structured framework for future interconnection investment, particularly for offshore hybrid assets and multi-purpose interconnectors. The government has stated that the objective is to create a coordinated and cost-efficient delivery framework while reducing investor risk. (GOV.UK)

C. India

In India, interconnection investment is closely associated with the Electricity Act 2003, central transmission planning, Central Electricity Regulatory Commission (CERC) regulations and the role of transmission utilities/system operators.

For inter-State transmission projects, regulatory approval can determine whether a proposed transmission scheme may proceed and how associated costs are treated.

A useful example is Power Grid Corporation of India Ltd v Karnataka Power Transmission Corporation Ltd, concerning regulatory approval for associated transmission systems intended, among other things, to achieve synchronous interconnection. The case demonstrates the importance of formal regulatory approval for major interconnection-related transmission investments. (CaseMine)

5. Stages of Regulatory Approval

A typical interconnection project may pass through the following stages:

Stage 1: Identification of system need

The system operator or transmission planner identifies a requirement for additional capacity.

For example:

Country A has excess renewable generation while Country B experiences electricity shortages during particular periods.

An interconnector could potentially allow electricity to flow between the two systems.

Stage 2: Technical feasibility

The system operator assesses:

voltage stability;

frequency stability;

short-circuit levels;

thermal limits;

power-flow constraints;

protection systems;

converter technology;

system restoration requirements; and

compatibility between the networks.

This stage is particularly important for HVDC interconnectors and asynchronous systems.

Stage 3: Cost-benefit assessment

The project promoter must demonstrate that expected benefits justify the investment.

Benefits may include:

B=Btrade+Bsecurity+Bcongestion+Brenewables+BreliabilityB = B_{trade}+B_{security}+B_{congestion}+B_{renewables}+B_{reliability}

against:

C=Cconstruction+Coperation+Cmaintenance+CenvironmentalC=C_{construction}+C_{operation}+C_{maintenance}+C_{environmental}

The regulator may consider whether:

B>CB>C

over the project's economic life.

Stage 4: Regulatory investment decision

The competent regulator determines whether the project should receive regulatory approval.

The decision may address:

project necessity;

efficient capital expenditure;

financing structure;

ownership;

allowed return;

cost recovery;

construction timetable;

performance obligations; and

consequences of delay.

Stage 5: Planning and environmental consent

Investment approval does not necessarily give permission to construct.

Separate approvals may be required for:

land;

marine areas;

environmental impacts;

protected habitats;

overhead lines;

substations; and

cable routes.

This separation is legally important because a regulator may consider a project economically justified while another authority may impose conditions concerning environmental or planning impacts.

Stage 6: Connection approval

The interconnector must satisfy the technical requirements of the networks to which it will connect.

The legal principle is generally that connection conditions should be based upon objective and non-discriminatory criteria.

The CJEU has considered precisely this question in Sabatauskas and Others (C-239/07) and subsequent electricity-network litigation. EU law does not necessarily allow users to choose whichever network they prefer; the classification and connection arrangements can depend upon objective regulatory and technical characteristics. (EUR-Lex)

6. Regulatory Consent and Cost Recovery

One of the most important questions is:

Who ultimately pays for the interconnection?

Possible models include:

1. Regulated asset model

The transmission operator invests and recovers efficiently incurred costs through regulated network charges.

2. Merchant interconnector

The private investor assumes greater investment risk and obtains revenue from interconnection capacity or price differences.

3. Hybrid model

Investment costs and market revenues are combined with some degree of regulatory support.

4. Public financing

The project may receive governmental or EU-level financial support because of wider strategic benefits.

The choice of model affects the level of regulatory scrutiny.

7. Congestion Revenue and Investment

Interconnectors can generate congestion revenue when electricity prices differ between connected markets.

EU law has specifically addressed the use of congestion income.

In Bayerische Motoren Werke AG (C-454/18), the Court of Justice examined the treatment of revenues associated with cross-border interconnectors. The Court held that operation and maintenance costs cannot simply be treated as network investments for the purpose of the relevant provision; genuine investment aimed at maintaining or increasing interconnection capacity is treated differently. (EUR-Lex)

This distinction is significant because regulators must prevent congestion revenues from being used in a manner inconsistent with the statutory purpose of the revenue mechanism.

8. Interconnector Exemptions

A particularly important form of regulatory consent concerns exemption from ordinary third-party-access and tariff rules.

EU Regulation 2019/943 permits exemptions for certain new interconnectors where specified conditions are satisfied.

Among the relevant conditions are that:

investment enhances competition or security of supply;

the investment would not occur without the exemption;

the interconnector is legally separate from the relevant system operators;

users are charged;

costs have not already been recovered through network charges; and

the exemption would not undermine competition or the functioning of the regulated system. (EUR-Lex)

Thus, exemption approval is itself a form of regulatory consent linked to investment risk.

9. Important Case Law

Case 1: Aquind Ltd v ACER

The Aquind litigation is particularly important for cross-border interconnector regulation.

Aquind concerned a proposed electricity interconnector between the UK and France and an application for exemption from certain regulatory requirements. The project initially involved regulatory authorities in France and the UK, with ACER becoming involved when the national regulators could not reach agreement. (EUR-Lex)

The litigation demonstrates several principles:

interconnector exemptions require formal regulatory assessment;

national regulators may have shared responsibilities;

ACER can have an important role where EU law gives it jurisdiction;

the legal status of the connected jurisdictions matters.

The later Aquind litigation also demonstrates the significance of Brexit. The General Court held that, following Brexit, the proposed UK-France connection was no longer an interconnector between two EU Member States for the purposes of the relevant EU regulatory provisions, affecting ACER's jurisdiction. (EUR-Lex)

Legal significance: regulatory consent depends not merely upon the physical existence of a cable but upon the applicable jurisdictional and statutory framework.

Case 2: Bayerische Motoren Werke AG (C-454/18)

This case concerned congestion revenues from cross-border interconnection.

The CJEU distinguished between:

ordinary operation and maintenance expenditure; and

genuine network investment intended to maintain or increase interconnection capacity.

The Court concluded that operation and maintenance costs could not simply be classified as network investment for the relevant regulatory purpose. (EUR-Lex)

Legal principle: regulatory approval of expenditure must correspond to the statutory purpose for which the relevant revenue is permitted to be used.

Case 3: Sabatauskas and Others (C-239/07)

The case concerned access to electricity networks and the relationship between transmission and distribution systems.

The CJEU emphasised that users do not necessarily have unrestricted freedom to choose the type of network to which they connect. The classification depends on the applicable legal and technical framework. (EUR-Lex)

Legal significance: interconnection and connection approvals must be consistent with objective network classifications rather than merely the commercial preference of the connecting party.

Case 4: Power Grid Corporation of India Ltd v Karnataka Power Transmission Corporation Ltd

This Indian regulatory proceeding concerned Power Grid's request for regulatory approval for associated transmission systems, including infrastructure associated with synchronous interconnection of the Southern Region with the NEW grid.

The matter illustrates the role of CERC regulatory approval in major inter-State transmission investment decisions. (CaseMine)

Legal significance: large interconnection investments require compliance with the applicable statutory and regulatory approval framework rather than relying solely upon the commercial decision of the transmission utility.

10. Regulatory Principles

Several general principles emerge.

A. Necessity

The project should address a demonstrable electricity-system requirement.

B. Proportionality

The regulatory burden and investment should be proportionate to the anticipated system benefits.

C. Non-discrimination

Connection and access decisions should not arbitrarily favour one market participant over another.

D. Transparency

The criteria for investment approval, connection and cost recovery should be sufficiently transparent to enable investors and network users to understand the regulatory framework.

E. Regulatory independence

Investment decisions should be made by competent authorities independently from commercial interests.

F. Consumer protection

Regulators must consider whether investment costs passed to consumers are justified.

G. Security of supply

Interconnection investment can be justified not only by commercial electricity trading but also by system-resilience and security-of-supply benefits.

H. Environmental compatibility

Economic approval does not remove the need to comply with environmental and planning legislation.

11. Problems in Interconnection Investment Approval

Interconnection projects create several legal challenges.

1. Regulatory uncertainty

Large infrastructure projects can take many years to obtain all necessary approvals.

2. Multiple regulators

Cross-border projects may involve two or more national regulators, system operators, planning authorities and environmental agencies.

3. Stranded-asset risk

Changes in electricity demand, renewable generation or energy policy can reduce the expected utilisation of an interconnector.

4. Cost allocation

A central question is whether costs should be paid by:

the connecting consumers;

all network users;

both participating countries;

project investors; or

some combination.

5. Cross-border jurisdiction

Different national laws may regulate the same physical infrastructure.

6. Market-power concerns

A privately owned interconnector can potentially acquire significant market influence, making competition and access rules important.

12. Relationship Between Investment Approval and Regulatory Consent

The two concepts can be represented as follows:

System need identified
↓
Technical feasibility
↓
Cost-benefit analysis
↓
Investment approval
↓
Planning/environmental consent
↓
Construction authorisation
↓
Grid connection approval
↓
Operational/licensing approval
↓
Market participation and capacity allocation

Investment approval therefore answers:

“Should this investment proceed?”

Regulatory consent answers:

“Under what legal conditions may this project be constructed, connected and operated?”

The two decisions are closely related but should not be legally conflated.

13. Conclusion

Interconnection investment approval and regulatory consent form a central part of modern electricity law. An interconnector is not merely a physical cable; it is a regulated infrastructure asset that can affect electricity markets, network security, consumers, competition and national energy policy.

The EU framework demonstrates how interconnection regulation combines cross-border market integration, investment incentives, congestion management and regulatory oversight. The Aquind litigation illustrates the importance of jurisdiction and exemption decisions, while Bayerische Motoren Werke demonstrates the legal distinction between ordinary operating expenditure and genuine investment in interconnection capacity. (EUR-Lex)

In India, regulatory approval of inter-State transmission and interconnection projects similarly illustrates the principle that major grid investments must operate within statutory and regulatory planning and approval mechanisms. The overall legal objective is to balance investment certainty, system reliability, market integration, environmental requirements and consumer protection.

Thus, effective interconnection regulation requires a coordinated approval architecture in which investment justification, technical connection, planning consent, licensing, environmental approval, cost recovery and market access operate as complementary elements of a single regulatory framework.