«The alternator was making a slightly abnormal noise. At first I didn’t give it any thought. Then he went off the rails.” In the words of a witness, elements arrive that can bring us closer to the truth about the explosion at the Bargi power plant on Lake Suviana. Enel Green Power employee Emanuele Santi was there when the massacre of the seven operators occurred. And he too, like others, talks about the alternator and the “strange noise” before the explosion. And he could also explain why some corpses had wounds on their backs: “They died while running away.” Meanwhile, the acquisition of the plant’s black box could give a turning point to the investigations. Which for now focus on three hypotheses to explain the explosion. That is, the mechanical failure, the electrical problem and the human error.”
«Away, everyone, out!»
Emanuele tells his truth to Corriere della Sera. He explains that when he arrived at the Suviana power plant the 15 workers of the maintenance team which included workers from Siemens, Abb and Voith were already at work. «I have the habit of going down to greet them all. Sometimes I also bring coffee,” he says. «So I came down while they were doing the testing. I heard the alternator making this slightly abnormal noise. At the beginning I didn’t give it too much weight”, he adds. Not to mention strange smells coming from the system. Those heard by middle school students on a trip to the area. And in the meantime they were denied by one of their professors. Santi, on the other hand, speaks of an “absurd” noise, as if someone was “shaking” the car. And of an “overrevving” that “became stronger and stronger, it never stopped”. Then, the drama: «When I understood I started shouting: “Come away, everyone, get out!”. And I ran up.”
The -8 floor
At that point, he recalls, everything exploded. All the workers who were near the site of the explosion died. Same fate for those who were near the turbine. The others, injured, burned and intoxicated. They managed to reach the exit and save themselves. Meanwhile Franco Cespa, head of the works at the Bargi power plant, tells The print that the part of the machine that broke was never touched by their work. «No one intervened on the generator. The only work done was the replacement of the cooling pipes. And some more protection has been added. Since it was born, the car has remained as it is. Except for periodic revisions.”
Short circuit
Cespa explains that before the explosion «colleagues told me they heard a loud noise, then explosions and flames. I think there was a short circuit inside the machine. It may be that a shaft bearing has cracked and the poles have touched the generator coils, causing a short circuit. The tests were between 120 and 130 megawatts. This caused a significant detonation.” Other elements could arrive from the so-called black box of the plant. That is, the Scada supervision and control system. The prosecutor’s office will now order a computer assessment. While in the next few days the seizure of documents relating to contracts and subcontracts will arrive. In total, there are six companies involved in Bargi. For checks on compliance with safety protocols.
Three hypotheses
Meanwhile, there are three hypotheses that could explain what happened to the Suviana power plant. The first is that of mechanical failure. A faulty component could have caused the misalignment between the alternator and turbine. Causing a cascade of electrical problems. Or the opposite could have happened. That is, a fault in the electrical system caused a mechanical failure. Finally there is the hypothesis of human error. One could be the failure to activate safety systems that were disconnected during the works. While the acrid smell smelled by some witnesses may have been caused by the cooling oil catching fire. Or from the friction between the mechanical parts.
The turbine and the lubricating oil
From this perspective, he explains The messenger, it could have been the turbine that overheated the oils. The machine is located on floor -9. The alternator was at -8. To allow the rotational movement of the turbine there are bearings that contain lubricating oil. Each bearing contains approximately three thousand litres. And that very material could have been the trigger. The turbine overspeeds, the oil overheats, the turbine falls apart and causes sparks that set the lubricant on fire. «The alternator was generating electricity as happens during operation, these are technical tests that are carried out on various parameters. There were no exceptional conditions, it was a standard test, nothing abnormal. There could be various types of causes at the origin of the accident, we have to think about it, it is difficult to give answers now”, says the CEO of Enel Green Power Salvatore Bernabei.
