The Regulatory Authority has blamed “critical deficiencies” at Belco for an island-wide 2020 blackout in a highly redacted report.

The report found that the main causes of the outage were the failure of an unnamed system and that certain circuit breaker settings were at factory settings instead of recommended settings.

An RA spokeswoman said yesterday: “The extensive technical reviews, which included numerous rounds of assessments and independent reviews between the Belco and RA, identified several critical deficiencies which contributed to the outage.

“Numerous improvements and recommendations have been made to Belco, including a review of the entire new North Power Station commissioning process.”

Asked to explain the large number of redactions in the report, the spokeswoman said: “Typically information is redacted to protect confidential information.

“Additionally, in this case, redactions are in place to protect sensitive critical infrastructure information, which for national security, should not be in the public domain.”

The report said the blackout started at about 10.15am on December 18, 2020 shortly after Belco launched “scheduled maintenance activity” at the North Power Station.

“All of the engines at the recently commissioned North Power Station were shut down following a loss of power to the [redacted],” the report said.

“The sudden loss of generation at the North Power Station resulted in the remaining available generation being insufficient to meet system demand, resulting in the further tripping of the single running engine at the East Power Station and a battery energy storage system, and a total loss of Belco-owned generation on the island.

“Supplies were fully restored at 6.57pm.”

Several root causes were given for the outage, however, each of the listed causes were subject to redactions.

Among the listed causes were a “functional failure” of a bypass function, an installation that had not been carried out to contract specifications, incorrect instructions mounted on a control panel and failure to “conduct commissioning and testing of the [redacted] in accordance with the contract”.

The Belco final report also identified a problem with the engine control system, although the issue was not linked to the outage.

“While it does not appear that this issue had any tangible impact on the outage, it did cause some confusion during the investigation,” the report said.

“Meaningful and correct alarm legends are important in both real time, so that operators are receiving accurate information about system conditions, and also after an event for review purposes.”

A Belco spokesman said the company welcomed the report and said the outage was the result of staff performing a standard operating procedure, which sparked an equipment failure.

“This caused a cascade of built-in safety mechanisms to be triggered that ultimately shut off power to the entire island,” the spokesman said.

“When the fault occurred, the safety mechanisms performed as designed and prevented what could have been serious damage to the generating equipment and grid and further delays for repairs and restoration of power.”

The spokesman added that throughout the incident and the subsequent investigation Belco was in constant communication with BWSC, who built and commissioned the plant, and the RA.

“Belco, in collaboration with BWSC, identified the root cause of the failure and has taken steps to resolve the issue,” the spokesman said. “The Belco investigation found that the outage resulted from a failure of the uninterruptible power supply that supports the North Power Station.

“Working with BWSC, the UPS was modified, tested and commissioned successfully. In addition, Belco commissioned an independent audit performed by a third party to review of the commissioning process of the NPS, which has since been providing reliable power to Bermuda for the last 18 months.”

He added that the company would review the reports and continue to work with the RA to implement all recommendations and actions outlined.