Iberdrola's EUR 25 million hydro withholding fine, later annulled
CNMC found that Iberdrola Generación progressively raised the offer prices of its Duero, Sil and Tajo hydro units from 30 November to 23 December 2013, cutting their day-ahead dispatch while prices were historically high so that dearer combined-cycle plants set a higher price. It fined the company EUR 25,000,000 under the former Electricity Sector Law; the ACER register lists the decision as annulled.
On this page
The decision
- Authority
- National Commission on Markets and Competition (CNMC), Spain
- Decided
- 24 November 2015
- Participants
- Iberdrola Generación S.A.U.
- Commodity
- Electricity
- Market
- Spanish wholesale electricity market (MIBEL)
- Conduct period
- 30 November to 23 December 2013
- REMIT
- Article 5 (Market manipulation)
- Type of conduct
- Economic withholding
- Penalty
- EUR 25,000,000, annulled
- Status
- Annulled (ACER register, 2026-10-14)
What CNMC found
In resolution SNC/DE/0046/14 of 24 November 2015, CNMC found that Iberdrola Generación progressively increased offer prices for its Duero, Sil and Tajo hydro units from 30 November to 23 December 2013, reducing their day-ahead dispatch. It found that this displaced hydro generation so that dearer combined-cycle plants set a higher price.
CNMC compared the offers with November: the average energy offered below EUR 70/MWh fell from 78 GWh to 13 GWh a day, while energy above EUR 90/MWh rose from 41 GWh to 105 GWh. It recorded day-ahead averages around EUR 80-90/MWh between 12 and 21 December, while Iberdrola's dispatch fell from 51 GWh on 29 November to under 20 GWh.
CNMC found no hydrological justification: reservoirs were above December 2011 levels and twice those of December 2012, yet output was lower than in both comparison periods. It also examined forward prices. First-quarter 2014 quotations had remained below spot, reaching about EUR 64/MWh; even applying a 1.25 factor, CNMC held that the resulting water value should have allowed more hydro dispatch.
What the decision turned on
Iberdrola argued that increasing offer prices was lawful, it was conserving water for later peak periods and its net purchasing position gave it no incentive to raise prices. It supplied expert reports and pointed to other generators' offer increases. CNMC rejected those explanations, finding that the company had not produced its own forecast supporting prices above the forward market.
On position, CNMC excluded indexed contracts, last-resort supply and domestic coal, and found Iberdrola a net seller on all but four days. It held the strategy fraudulent because capacity was offered on terms intended to prevent dispatch, giving a decision not to generate an appearance of legality. It also cited REMIT Article 5 and ACER's withholding guidance. The conduct was sanctioned under the former Spanish Electricity Sector Law.
The penalty and later status
CNMC applied Article 60.a)15 of Law 54/1997 as more favourable than the replacement law. It weighed the duration of more than three weeks, the already high demand and prices, and the scale of the affected hydro units: 50% of installed hydro capacity and 86% of Iberdrola's. It estimated an approximately EUR 7/MWh price increase, EUR 21.5 million benefit to Iberdrola and EUR 105 million cost to demand. The fine was EUR 25,000,000.
ACER's register, transcribed on 14 October 2026, lists this decision as annulled. The findings above describe CNMC's original reasoning rather than an upheld determination. The judgment explaining the annulment was not available in the sources reviewed, so its grounds are not attributed here.
For a surveillance function
CNMC's original analysis compared offer changes with the same plants' history, reservoirs, forward prices and the company's position. It tested the contemporaneous economic explanation for conserving water, rather than treating low hydro output alone as evidence of withholding. The recorded annulment remains essential context when reading that analysis.
Sources
- CNMC, resolution SNC/DE/0046/14 (Iberdrola Generación), 24 November 2015 (Decision, in Spanish)
- CNMC, press release, 30 November 2015 (Press release, in Spanish)
- ACER, overview of REMIT sanction decisions (ACER register)
Sources read on 27 October 2026. This page restates what the authority published and adds no finding of its own. A decision under appeal is not final, and its status may have changed since: check the source before relying on it.