Minister: Blackout waiting to happen
Faulty design of NGC bypass system...
Julien Neaves email@example.com
THE NATIONWIDE blackout last Friday was “waiting to happen” because of inadequate infrastructure at the Phoenix Park Gas Processors Ltd (PPGPL) facility at Point Lisas and in the overall power generation system.
This was stated yesterday by Energy Minister Kevin Ramnarine in a statement to the Senate on the blackout, at Tower D, International Waterfront Centre, Port of Spain.
Ramnarine explained that the PPGPL plant, through which all natural gas passes and is processed for downstream users, has a bypass system in the event that it is down, which comprises three lines with associated valves, two operated by the National Gas Company (NGC) and one within PPGPL.
At 12.22 a.m. on March 29, the PPGPL emergency shutdown system was activated, resulting in the stoppage of gas flow through the plant. The bypass valve at PPGPL and both NGC valves opened, but “unusually high pressures” caused the PPGPL bypass valve to shut in, stopping the flow of gas through the PPGPL bypass line.
He explained that the NGC automatic bypass system consists of four bypass valves— “A, B, C and D”. A and B were installed with the first phase of PPGPL in 1991 and C and D with the second phase in 1998. In 2009, PPGPL completed its third expansion, “however, this time, there was concomitant expansion of the NGC automatic bypass facility”.
He said this was the “root of the problem we experienced on Good Friday. It was simply waiting to happen”.
He continued: “I can now tell the Senate and the public that this deficiency in the design of the NGC bypass system will be rectified.”
According to Ramnarine, with the sudden loss of gas flow, the supply pressure to downstream users at Point Lisas “plummeted within minutes”. He further explained that the low pressure then caused the PowerGen plant at Point Lisas, which requires gas to be supplied to it at a certain level, to trip out of service.
The drop in pressure, he continued, also resulted in PowerGen Penal, PowerGen Wrightson Road and Trinity Power in Couva all tripping. He noted, however, that at no time was there a cessation of natural gas supply to the Trinidad Generation Unlimited (TGU) power plant at the Union Industrial Estate, La Brea, “but it did suffer the loss of its auxiliaries and experienced a total shutdown”.
He explained that the loss of power in Trinidad caused the loss of four megawatts of power from the submarine cable supplying Tobago. He noted that in an attempt to pick up the loss of supply, three generating units at the Trinidad and Tobago Electricity Commission (T&TEC) plant at Cove Estate was shut down due to operator error, which resulted in a total loss of power in Tobago at 1.29 a.m., and the country was in a state of “nationwide blackout”.
The error at Cove was currently under investigation by T&TEC, Ramnarine said.
He noted the natural gas system at NGC was normalised and an all-clear given to restart power generation facilities at 1.15 a.m. in Trinidad; the PowerGen Penal station was able to restart its number seven unit and, consequently, there was recovery of power throughout the country. By 7.15 p.m., T&TEC’s restrictions to industrial customers were lifted, he said.
He said while the Point Lisas Industrial Estate was disrupted for 24 hours, all plants were back online with the exception of one. He noted the blackout also impacted operations of Petrotrin’s refinery, and it was currently in the process of getting back to its maximum throughput of 160,000 barrels of oil per day.
Ramnarine said on the instruction of Prime Minister Kamla Persad-Bissessar, a report is being prepared for Cabinet consideration and a preliminary version will be submitted tomorrow. He noted the companies involved have already submitted their reports, and they were being collated by his ministry and the Public Utilities Ministry.
to strengthen the
natural gas power electricity system
According to Energy Minister
1. Installation of dual fuel capacity at selected stations, so liquid fuel such as diesel would be in storage in event the natural gas supply is compromised.
2. Installation of requisite infrastructure to evacuate all the power that can be generated by Trinidad Generation Unlimited (TGU) and bring the power to national grid. TGU has a capacity of 720 megawatts and currently supplying below 300 megawatts to T&TEC because of infrastructural constraints, according to Ramnarine. The infrastructure required is two 220 kilovolt lines from La Brea and a new substation in Gandhi Village, Debe, he said.
3. Ensure every power plant in Trinidad and Tobago has a reliable “black-start” capability— this a system that allows a power plant to self-start.
4. National Gas Company (NGC) to install additional bypass capacity so it will become “fully independent” of the PPGPL bypass system.