Coupling of Wholesale, Balancing, and Retail Markets

Detailed Explanation With Case Laws

1. Introduction

Market coupling means linking different electricity-market segments so that electricity, balancing resources, network capacity and price signals work together. The main segments are the wholesale market, balancing market and retail market.

In a modern electricity system, these markets cannot operate completely separately. Wholesale markets arrange electricity purchases and sales, balancing markets correct differences between expected and actual generation and demand, while retail markets connect suppliers with final consumers.

The European Union provides a useful legal model because its electricity-market rules are designed to integrate national markets and different trading timeframes. ACER explains that EU market rules aim to improve market integration, efficient use of infrastructure, competition, transparency and security of supply. (Acer Europe)

2. Meaning of Wholesale Market Coupling

The wholesale market includes forward, day-ahead and intraday trading.

Market coupling allows electricity bids from different countries or bidding zones to be considered together. Available cross-border transmission capacity is allocated together with electricity trades.

Under the EU Capacity Allocation and Congestion Management (CACM) Regulation, single day-ahead and intraday coupling is used to allocate cross-zonal capacity efficiently. The system collects bids from different bidding zones and seeks to maximise economic surplus. (Acer Europe)

This can reduce unnecessary price differences between connected markets and make better use of interconnectors.

3. Coupling with Balancing Markets

Wholesale trading cannot predict electricity production and consumption perfectly. Wind output, demand, plant failures and weather can create unexpected differences.

The balancing market corrects these differences.

The EU Electricity Balancing Regulation provides common rules for:

procurement of balancing capacity;

exchange of balancing capacity;

activation of balancing energy;

imbalance settlement; and

settlement between transmission system operators (TSOs). (Acer Europe)

European balancing platforms allow balancing bids from different countries to compete. This means that a TSO can potentially obtain balancing energy from resources outside its own national market, subject to network and technical constraints. (Acer Europe)

4. Connection with Retail Markets

The retail market deals directly with consumers and suppliers.

Coupling wholesale and retail markets means that wholesale price signals can increasingly influence retail products. Examples include:

time-of-use tariffs;

dynamic electricity prices;

demand-response programmes;

smart-meter-based consumption;

flexible tariffs; and

consumer participation in balancing services.

A household with a smart meter, for example, may reduce consumption when wholesale or system prices are high. Aggregators can combine many small consumers and offer their flexibility to electricity markets.

Therefore, retail consumers can become not only electricity users but also active market participants.

5. Legal and Regulatory Framework

The EU framework connects the three market levels through several regulations.

The CACM Regulation 2015/1222 governs day-ahead and intraday market coupling.

The Electricity Balancing Regulation 2017/2195 establishes common balancing-market principles.

The Electricity Regulation 2019/943 provides broader rules concerning the internal electricity market, network access, congestion management and system operation. (Acer Europe)

ACER and national regulatory authorities supervise implementation, while TSOs and nominated electricity market operators (NEMOs) perform important operational functions.

6. Benefits of Market Coupling

Market coupling can provide several benefits.

A. Better Use of Interconnectors

Electricity can flow toward areas where it has greater economic value, subject to available network capacity.

B. More Competition

Generators and balancing providers may compete across a larger market.

C. Better Integration of Renewables

Variable renewable generation can participate in wider markets, while balancing resources can be shared across borders.

D. Consumer Benefits

Better integration can contribute to more efficient wholesale prices and provide consumers with greater opportunities to respond to price signals.

ACER identifies efficient infrastructure use, competition, security of supply and cost-reflective price formation among the objectives of integrated electricity markets. (Acer Europe)

7. Relevant Case Laws

VEMW and Others, Case C-17/03

The Court of Justice held that EU electricity-market rules concerning non-discriminatory network access could prevent preferential allocation of cross-border transmission capacity. (curia)

Relevance: The case supports the principle that cross-border electricity markets should operate on transparent and non-discriminatory access rules.

AEM and AEM Torino, Joined Cases C-128/03 and C-129/03

The Court considered electricity transmission-system access charges and the principle of non-discrimination under the earlier electricity-market framework.

Relevance: It demonstrates the importance of equal treatment when designing charges and access arrangements.

Ålands Vindkraft, Case C-573/12

The Court considered a Swedish renewable-energy support scheme and its relationship with the free movement of goods. The judgment illustrates the tension between national energy policies and the development of an integrated European energy market. (InfoCuria)

Prezident Slovenskej republiky, Case C-378/19

The Court examined the independence of national electricity regulators under the EU internal electricity-market framework. (curia)

Relevance: Independent regulation is essential when wholesale, balancing and retail markets are increasingly interconnected.

8. Conclusion

Coupling of wholesale, balancing and retail electricity markets creates a more integrated electricity system. Wholesale markets determine much of the commercial value of electricity, balancing markets correct real-time differences between supply and demand, and retail markets transmit price signals to final consumers.

Effective coupling requires non-discriminatory access, transparent rules, coordinated network operation, independent regulation and reliable information systems. EU market-coupling rules provide an important example of this integrated approach. The long-term objective is to allow generators, suppliers, balancing providers and consumers to participate more efficiently while maintaining system security, competition and consumer protection.