Coupled markets that did not converge

Market coupling has a simple test. Two coupled zones should clear at the same price whenever the transmission capacity between them is sufficient to move power from the cheaper zone to the dearer one. Prices separate only when that capacity runs out.

So the price spread between coupled zones is not a market curiosity. It is a direct, hourly measurement of how often the link between them is the binding constraint.

What the trading day showed

On the day examined, Albania and Kosovo cleared at an identical price in none of the 24 hours.

The zones were separated across the entire day, with the widest gap in the low tens of euros per megawatt-hour. Both zones followed the same broad shape — falling overnight, rising into the evening — but at persistently different levels.

What separation means, and what it does not

It means the interconnector was binding. Power that would have flowed from the cheaper zone to the dearer one could not, so each zone cleared against its own supply stack. That is the definition of congestion, and it has a price attached.

It does not mean the coupling is failing. Coupling is functioning exactly as designed: it moves as much power as the network allows and prices the remainder separately. A day of full convergence would show the link had spare capacity; a day of full separation shows it did not. Both are the mechanism working.

It does not mean either market is illiquid or immature. Volumes are published alongside prices, and a separation pattern says nothing about depth on its own.

Why this is worth watching over time

A single day is an anecdote. The value is in the ratio measured continuously: what proportion of hours do these two zones clear together?

That figure is one of the cleanest available answers to a question that is otherwise argued qualitatively — does the interconnection between Albania and Kosovo need reinforcement, and how urgently? A link that binds in 10% of hours is behaving normally. A link that binds in most hours is a constraint on both markets, and the congestion rent it generates is a measurable input to the investment case for relieving it.

The same test applies to every coupled border in the region.

A note on sourcing

These prices come from ALPEX itself, the exchange that clears both zones. That matters because the ENTSO-E-derived feeds commonly used for regional price comparison do not expose the Albania or Kosovo bidding zones — an absence which says something about those feeds, and nothing whatever about whether the markets exist. They do, and they publish.