A synched Unit 6 at Costa Sur adds 410 MW of generation capacity to grid
By The Star Staff
Puerto Rico Electric Power Authority (PREPA) Executive Director Josué Colón Ortiz announced the startup and synchronization process of Unit 6 at the Central Costa Sur power plant on Thursday morning.
“It should be noted that Unit 6 had a major breakdown this year and that same year it was repaired and put into service,” the official said in a written statement. “Unit 6 of Costa Sur contributes about 410 MW [megawatts] of capacity to the energy system, and to the extent that PREPA’s most efficient and cost-effective units have been repaired and brought into service, the more stable the cost of electricity will be while the transition is made to safe and reliable renewable energy and cleaner fuels such as natural gas.”
Colón Ortiz referred to the startup process of Unit 6 as a gradual and complex one, since the process begins with the pressurization of the boiler, where various components of the thermodynamic cycle are verified, so that all the factors meet the turbine break-in requirement. Once the boiler was pressurized, he said, the break-in process began, verifying the operational parameters of the turbine.
With the turbine rotating at speed to synchronize, the parameters of the thermodynamic cycle continue to be monitored, such as pressures and temperatures at different points in the cycle. As soon as the unit parameters are appropriate, it can be safely and reliably interconnected or synchronized with the electrical system, the official said.
Once the unit has been synchronized with the island’s electrical system, in coordination with the Energy Control Center operated by the transmission and distribution system manager LUMA Energy, the goal is to reach 20 percent of the unit’s load, which in the case of Unit 6 is 100 MW.
The repaired rotor of the Unit 6 turbine arrived in Puerto Rico on Dec. 8, after the environmental maintenance of the boiler and its auxiliary equipment was carried out as part of a mutual agreement with the U.S. Environmental Protection Agency. That work included maintenance and repairs to the boiler, air preheaters, funnel, ducts, induced draft fans and forced draft fans, and all auxiliary equipment such as turbine-driven feed pumps, condenser circulation pumps, pump boiler circulation, and boiler and turbine valves.
The approximate cost of the work done at Unit 6 along with the repair of the low-pressure rotor is $5 million.