Blog Post

Market coupling does not lower prices!

Market coupling is one of the key-policies for achieving the EU single electricity market. The EU Commission praises the price-lowering effects of market integration in the first draft of the Internal Market Communication of August 30th: “wholesale electricity prices in the EU have risen much less thanks to competition facilitated by increasing cross-border trading and […]

By: Date: September 28, 2012 Topic: Innovation & Competition Policy

Market coupling is one of the key-policies for achieving the EU single electricity market. The EU Commission praises the price-lowering effects of market integration in the first draft of the Internal Market Communication of August 30th: “wholesale electricity prices in the EU have risen much less thanks to competition facilitated by increasing cross-border trading and market integration”.

And common sense would indeed suggest that in competitive markets the average price of two market zones will be equal or lower when they are coupled than when they are separate. In fact, coupling should lead to lower average prices for typical electricity markets (increasing marginal cost on the supply side and price-inelastic demand). The intuitive reason is that the most expensive MWh in the expensive country might be replaced by switching on one additional MWh in the cheaper country. As marginal cost is increasing the switched-off MWh will be disproportionally more expensive than the switched on MWh. In our example (see Figure 1) in the first market 10 MWh with marginal cost of 158-176 EUR are switched on while 10 MWh with marginal cost of 176-239 EUR are switched off.

Figure 1: Market coupling with well behaving cost functions under perfect competition

Market 1:

Marginal Cost = Volume(1.1)

Demand = 100

Market 2:

Marginal Cost = Volume(1.4)

Demand = 50

In a Cournot competition setting this effect is amplified by the increase in the number of players in the joint market. This increased competition in the joint setting will drive down prices compared to the separate market setting. In our example (see Figure 2) coupling two monopolistic markets (with similar cost curves) to one duopolistic market drives down the average price by 7 percent.

Figure 2: Market coupling with well behaving cost functions under imperfect competition

Market 1:

Cost = ½*Volume2

Demand = 300-Volume

Market 2:

Cost = ½*Volume2

Demand = 300-2xVolume

The above illustrated supply curve smoothing and competition enhancing  effect of market coupling would suggest, everything else being equal, that consumers in two markets in total face lower electricity bills when the markets are coupled, then when they are not.

We now move on to test this important proposition empirically using European spot electricity prices. The hypothesis is that at a given total demand in the two markets, average prices are typically lower when the markets are coupled than if they are decoupled. In Figure 3 the relation between load-weighted average prices (in €/MWh) in the Franco-German market and total volume (in GWh) in the Franco-German market is depicted (green dots). Thereby, the upper subplot only plots the instances were electricity prices in both countries are close to equal (price difference less than 5%) while the lower subplot restricts the sample to hours where the prices were differing by more than 5%. To make the subplots comparable the polynomial approximation to the volume-price relation has been depicted in both cases as a line.

Figure 3: Weighted average Franco-German price for coupled and decoupled hours in 2010

In Figure 4 the prices in both cases are compared. Based on the flattening supply curve and the competition effect one would expect that the red line that represents the average price when markets are decoupled is systematically higher than the blue line that represents the average price when markets are coupled (the lines are polynomial approximations to the price/volume curve). The surprising result is that price equalization (coupling) does only lead to a slightly lower average price at very high levels of electricity demand for the depicted Franco-German case.

Figure 4: Comparison of the weighted average Franco-German price for coupled and decoupled hours in 2010


 

This finding can be reproduced for many years and country combinations (see Figure 5). The only exception from this rule was the Germany-Nordic market combination in 2008 that featured significantly lower prices when the markets were coupled, than when they were not. Results are also not sensitive to the difference threshold. The figures for the 1% and 10% threshold for all 12 cases are suggesting no systematically higher price in case of decoupling like the here reported 5% threshold results.

Figure 5: Comparison of the weighted average prices for coupled and decoupled hours in various European markets

The presented findings are still very preliminary. If they can be confirmed more generally they would point to the conclusion that market coupling is much less beneficial for final customers than one might have expected. In this case, identifying the reasons why market coupling does not drive down prices is required to be able to reap the full benefits of market integration for consumers.

One possible explanation could be the sometimes unusual shapes of electricity cost curves (compared to microeconomic textbook cost curves). When moving to a cost function with a long flat left that become very steep at the right end the above outlined proposition that market coupling leads to lower average prices (due to the flattening supply curve and the competition effect) does not need to hold anymore. As illustrated in the below example (see Figure 6) the price might converge to the higher price when the more sizable low price zone is forced to accept higher prices due to coupling. More research on under which conditions to expect rising/falling prices from market coupling is necessary. This possibly needs to involve supply function equilibria to address the effects of oligopolistic competition in market integration.

Figure 6: Market coupling with non-linear cost functions under perfect competition

Just to be clear, the presented findings do not challenge the view that coupling markets is welfare enhancing. In all presented simulations, total welfare after coupling is larger or equal than in the uncoupled case. The results do also not allow deductions on additional benefits of market coupling such as potentially reduced volatility. So the sole finding I would like to put up for discussion is that market coupling might not have reduced average wholesale prices and hence did not increase consumer rents. I would encourage all readers to enlighten me on what might have caused this finding that was completely contrary to my prior expectation.

———————————————————————————————————————————————————————–

PS

Figure 7

Figure 8


Republishing and referencing

Bruegel considers itself a public good and takes no institutional standpoint. Anyone is free to republish and/or quote this post without prior consent. Please provide a full reference, clearly stating Bruegel and the relevant author as the source, and include a prominent hyperlink to the original post.

View comments
Read article More on this topic More by this author

Blog Post

Do AI markets create competition policy concerns?

AI markets are young and their structure is yet to crystallise. Is European competition law ready for what happens next?

By: Julia Anderson Topic: Innovation & Competition Policy Date: January 23, 2020
Read about event

Upcoming Event

Jan
28
09:30

A post-Brexit agreement for research and innovation

What is the future of EU's and UK's relationship on research and innovation?

Speakers: Adrian Hayday, Philippe Lamberts, Michael Leigh, Clare Moody, Martin Muller, Joe Owen, Jaroslaw Pietras, Uta Staiger, André Sapir, Beth Thompson and Guntram B. Wolff Topic: European Macroeconomics & Governance, Innovation & Competition Policy Location: Bruegel, Rue de la Charité 33, 1210 Brussels
Read about event

Past Event

Past Event

The state of health in the EU and the digitalisation of health promotion

The panellists at this event reviewed the general state of health as well as the digitalisation in the industry.

Speakers: Stefania Boccia, Caroline Costongs, Katarzyna Czabanowska, Zsolt Darvas, Guillaume Dedet, Martin Dorazil, Josep Figueras, Joanna Kokot, Martin Seychell and Michael Strübin Topic: European Macroeconomics & Governance, Innovation & Competition Policy Location: Bruegel, Rue de la Charité 33, 1210 Brussels Date: January 22, 2020
Read about event More on this topic

Past Event

Past Event

The European AI policy: writing the first lines of the code

At this closed-door event, an open discussion with Margrethe Vestager will contribute to her work on artificial intelligence. The aim of these discussions is to set out a policy and regulatory approach in the form of a white paper, including the human and ethical implications of AI.

Speakers: Margrethe Vestager and Guntram B. Wolff Topic: Innovation & Competition Policy Location: Bruegel, Rue de la Charité 33, 1210 Brussels Date: January 21, 2020
Read article More on this topic More by this author

Podcast

Podcast

AI in Europe: a conversation with Google's CEO

It seems almost inevitable that Google will be big part of Europe's future. And Europe will be a huge part of Google's too. This week, Alphabet, Google's parent company, hit $1 trillion market cap for the first time. Can Google's AI be socially beneficial? Are big tech companies intrinsically bad? This week, Guntram Wolff talked to Google and Alphabet's CEO, Sundar Pichai.

By: The Sound of Economics Topic: Innovation & Competition Policy Date: January 20, 2020
Read about event More on this topic

Upcoming Event

Feb
5
12:00

The quality and quantity of work in the age of AI

At this event, the panelists will discuss the implications of Artificial Intelligence on the labour market and the future of work in general.

Speakers: Robert Atkinson, Anna Byhovskaya, Maria Demertzis, Carl Frey and Daniel Samaan Topic: Innovation & Competition Policy Location: Bruegel, Rue de la Charité 33, 1210 Brussels
Read about event More on this topic

Past Event

Past Event

Partnering with Europe on responsible AI: a conversation with Sundar Pichai, CEO Google and Alphabet

At this event, Google's and Alphabet's CEO Sundar Pichai will elaborate on his views on Artificial Intelligence.

Speakers: Sundar Pichai and Guntram B. Wolff Topic: Innovation & Competition Policy Location: SQUARE, Mont des Arts, 1000 Brussels Date: January 20, 2020
Read about event More on this topic

Upcoming Event

Mar
9
10:30

Modernising European Competition Policy

The event addresses the need for modernising European competition policy due to structural changes in the economy caused by shifting global economic landscapes on the one hand and ongoing digitization of the economy on the other.

Speakers: Alicia García-Herrero, Georgios Petropoulos, Eddy de Smijter, Philipp Steinberg, Achim Wambach and Guntram B. Wolff Topic: Innovation & Competition Policy Location: Bruegel, Rue de la Charité 33, 1210 Brussels
Read article More on this topic More by this author

Opinion

Could the U.S. economy be experiencing a hidden tech-driven productivity revolution?

In the last decade, most advanced economies have grown more slowly than before. Slower growth has frequently been seen as a legacy of financial crises, especially that of 2007–2009.

By: Marek Dabrowski Topic: Innovation & Competition Policy Date: January 6, 2020
Read article More on this topic More by this author

Blog Post

AI and the Productivity Paradox

In this blog post, I review the main explanations for this paradox and I briefly discuss relevant policy options in order to increase the contribution of AI on productivity

By: Georgios Petropoulos Topic: Innovation & Competition Policy Date: December 24, 2019
Read article More by this author

Blog Post

2019 on #econtwitter, in a million tweets

What did academic economists talk about in 2019? I collected one million tweets from popular academic economists over the year, and analysed the topics discussed.

By: Enrico Bergamini Topic: Energy & Climate, European Macroeconomics & Governance, Finance & Financial Regulation, Global Economics & Governance, Innovation & Competition Policy Date: December 19, 2019
Read article Download PDF More on this topic More by this author

Policy Contribution

Bridging the divide: new evidence about firms and digitalisation

Small European firms are falling behind in the race to digitalise, but so are their American counterparts.

By: Reinhilde Veugelers Topic: Innovation & Competition Policy Date: December 11, 2019
Load more posts