Both executives appeared before a congressional oversight committee to answer lawmakers' questions, days after the National Commission on Markets and Competition (CNMC) launched probes into leading energy firms for alleged "serious infractions" leading to the April 28 outage.
Mario Ruiz-Tagle, head of Iberdrola España, noted that while the regulator observed anomalous behavior at several Iberdrola plants, it did not directly link them to the blackout.
He added that once Iberdrola receives further details from the CNMC, "we will be able to understand the specific allegations and mount a defense."
GRID OPERATOR UNDER SCRUTINY
Endesa CEO José Bogas stated that his company's plants did not fail to meet their voltage control obligations on that day.
Instead, Bogas argued that the system operator, REE, should have brought more synchronous plants online, increased hydraulic capacity, or utilized gas-fired combined-cycle plants.
In Bogas's view, REE reacted too late and was therefore primarily responsible for the event -- though not necessarily at fault -- as it possessed the tools to prevent it.
Ruiz-Tagle echoed this sentiment, asserting that REE should have operated with wider safety margins that day, claiming it failed to respond in time and exacerbated the issue through many of the measures it took to manage voltage.
According to the antitrust watchdog, REE is being investigated for "very serious infractions," which could carry fines of up to 60 million euros (70.7 million dollars). The agency cites "causing a power supply interruption without justified cause or without following protocols, thereby affecting security" as an example of such violations.
REE stated that previous reports concluded the blackout was caused by multiple factors and "provided technical evidence that there was no infraction (on REE's part) that could have been a determining cause."
A report published last month by an expert group from the European association of grid operators, ENTSO-E, did not assign blame to any specific actor. Instead, it concluded the blackout resulted from a combination of factors, including oscillations, deficiencies in voltage and reactive power control, and uneven stabilization capabilities.
Endesa's Bogas claimed the ENTSO-E report contained numerous flaws and failed to address key issues, adding that a conflict of interest existed since REE is a member of the organization.
(1 dollar = 0.8486 euros)
(Reporting by David Latona; editing by Andrei Khalip and Stephen Coates; Spanish editing by Paula Villalba)
