Cross-Border Clearing System Coordination Rules

Detailed Explanation With Case Laws

1. Introduction

Cross-Border Clearing System Coordination Rules are legal and regulatory rules that coordinate the settlement of financial and energy transactions between different countries. In electricity markets, clearing and settlement are important because electricity can be traded across borders while the actual physical flow is managed by interconnected transmission systems.

The basic process is:

Cross-border electricity trade → Clearing → Settlement → Payment → Imbalance adjustment

The main purpose is to ensure that market participants, transmission system operators (TSOs) and other parties know who must pay, who receives payment, how prices are calculated and how cross-border imbalances are settled.

2. Meaning of Clearing and Settlement

Clearing is the process of determining the financial obligations arising from market transactions.

Settlement is the actual process through which those financial obligations are paid.

For example:

Supplier in Country A

→ buys electricity from

Market participant in Country B

↓

Transaction is cleared

↓

Amount payable is calculated

↓

Settlement takes place.

Cross-border transactions require common rules because the parties may be governed by different national legal systems.

3. Importance in Electricity Markets

Electricity cannot normally be stored easily in large quantities. Therefore, generation and consumption must remain balanced.

If a market participant produces or consumes more or less electricity than scheduled, an imbalance arises.

EU Regulation 2017/2195 on electricity balancing provides rules for imbalance settlement and requires TSOs to settle calculated imbalances with balance-responsible parties against the applicable imbalance price. (Eur-Lex)

This makes clearing and settlement an important part of electricity-market governance.

4. Cross-Border Coordination

Cross-border coordination is necessary because electricity markets are interconnected.

For example:

Country A

↓

Interconnector

↓

Country B

↓

Balancing and settlement systems

If the two countries use completely different settlement rules, cross-border trading becomes complicated.

Therefore, coordination may cover:

transaction confirmation;

capacity allocation;

balancing;

imbalance settlement;

payment arrangements;

collateral;

data exchange;

invoicing; and

dispute resolution.

5. EU Electricity Balancing Framework

The main EU framework includes Commission Regulation (EU) 2017/2195, known as the Electricity Balancing Guideline.

It establishes rules for cooperation between TSOs and for European platforms dealing with balancing energy.

The Regulation provides for common settlement arrangements and coordinated mechanisms between TSOs, including rules concerning unintended exchanges of energy. (Eur-Lex)

This creates a more integrated approach to cross-border electricity balancing.

6. Imbalance Settlement

An important part of the system is imbalance settlement.

Suppose a supplier schedules:

100 MW

but actually consumes:

110 MW

The difference is:

10 MW imbalance

The applicable imbalance price determines the financial amount payable.

EU rules seek to ensure that imbalance settlement creates appropriate incentives for market participants to remain balanced. (Eur-Lex)

7. Cross-Border Balancing Platforms

European electricity markets use common platforms for exchanging balancing energy.

Important platforms include:

mFRR platform — manually activated frequency restoration reserves;

aFRR platform — automatically activated frequency restoration reserves; and

imbalance netting platforms.

These platforms allow TSOs in different countries to coordinate balancing resources.

This reduces the need for every country to solve balancing shortages independently.

8. Cross-Zonal Capacity

Cross-border clearing also depends on cross-zonal transmission capacity.

If Country A wants to purchase balancing energy from Country B, sufficient transmission capacity must be available.

Therefore:

Balancing requirement

↓

Available cross-zonal capacity

↓

Balancing energy activated

↓

Financial clearing and settlement

The Court of Justice specifically considered this relationship in Polskie Sieci Elektroenergetyczne v ACER.

9. Case Law: Polskie Sieci Elektroenergetyczne v ACER

In Joined Cases C-281/23 P and C-282/23 P, Polskie Sieci Elektroenergetyczne S.A. and Others v ACER, the Court of Justice delivered judgment on 23 October 2025.

The case concerned European platforms for exchanging balancing energy, the functions required to operate those platforms, and the use of cross-zonal capacity for balancing energy. (Eur-Lex)

Relevance

The case demonstrates that cross-border electricity clearing cannot be separated from:

balancing;

TSO cooperation;

European balancing platforms; and

cross-zonal transmission capacity.

It also confirms the important regulatory role of ACER.

10. Case Law: Austrian Power Grid v ACER

In Austrian Power Grid and Others v ACER, Case T-606/20, the General Court considered ACER's competence concerning the European platform for the exchange of automatically activated balancing energy (aFRR).

The case concerned the rejection of a joint proposal submitted by TSOs and issues including ACER's competence, reasoning and procedural rights. (InfoCuria)

Relevance

The case shows that cross-border clearing and balancing arrangements require legally valid common methodologies and regulatory decisions.

11. Case Law: Austrian Power Grid v ACER

A related case, Case T-607/20, concerned the European platform for the exchange of balancing energy from manually activated frequency restoration reserves (mFRR).

The General Court examined issues concerning the procedure for adopting common terms, conditions and methodologies and ACER's competence. (InfoCuria)

Relevance

The case demonstrates the importance of coordinated regulatory frameworks when several TSOs operate across national borders.

12. Case Law: Swissgrid v ACER

In Swissgrid v ACER, Case T-556/23, the General Court considered the European platform for the imbalance netting process and Swissgrid's non-participation in that platform.

The judgment of 8 October 2025 dealt with questions concerning ACER's decision, the implementation framework and the conditions for bringing an appeal before ACER's Board of Appeal. (Eur-Lex)

Relevance

The case shows that cross-border coordination can become legally difficult where a neighbouring country's TSO does not participate in a European platform.

13. Common Settlement Rules

Effective cross-border systems need common rules concerning:

calculation of obligations;

payment deadlines;

imbalance prices;

currency;

invoices;

collateral;

default;

corrections; and

reconciliation.

Without such rules, disputes can arise between TSOs and market participants.

Regulation 2017/2195 specifically requires coordinated mechanisms for settlement adjustments between TSOs. (Eur-Lex)

14. Data and Information Exchange

Clearing requires accurate information.

Market operators and TSOs may need to exchange:

scheduled electricity volumes;

actual metered volumes;

imbalance information;

prices;

transaction records; and

settlement data.

Errors in data can result in incorrect payments, so legal rules concerning data quality and correction are important.

15. Financial Security

Cross-border clearing systems may also require:

collateral;

guarantees;

credit limits;

payment security; and

default arrangements.

These measures protect the market if a participant fails to pay its financial obligations.

This is especially important because cross-border markets may involve parties subject to different insolvency and financial laws.

16. Dispute Resolution

A coordination framework should provide mechanisms for resolving disputes concerning:

settlement calculations;

imbalance prices;

metering;

capacity;

payment;

collateral;

platform participation; and

regulatory decisions.

Disputes may involve TSOs, market operators, regulators or ACER.

17. Importance for Renewable Energy

Cross-border clearing coordination is increasingly important because renewable generation is variable.

For example:

Unexpected wind increase

↓

Generation exceeds forecast

↓

System imbalance

↓

Balancing energy required

↓

Cross-border balancing platform activated

↓

Financial settlement between participants and TSOs

Thus, coordinated clearing systems support the integration of wind and solar generation.

18. Conclusion

Cross-Border Clearing System Coordination Rules provide the legal framework for coordinating the financial clearing and settlement of electricity transactions and balancing activities across national borders.

The EU system demonstrates how TSOs, market participants, balancing platforms and ACER can operate within a common regulatory structure. Regulation 2017/2195 is particularly important because it establishes common rules for electricity balancing and imbalance settlement. (Eur-Lex)

Cases such as Polskie Sieci Elektroenergetyczne v ACER, Austrian Power Grid v ACER, and Swissgrid v ACER show the legal importance of common balancing platforms, ACER's regulatory powers, cross-zonal capacity and coordinated methodologies. (Eur-Lex)

Overall, effective cross-border clearing requires common settlement rules, accurate data, coordinated balancing, secure payments, transparent methodologies and effective regulatory supervision. Such coordination is essential for a reliable and integrated international electricity market.