HAGÅTÑA (The Guam Daily Post) — The Guam Power Authority has been experiencing difficulty maintaining generation capacity, leading to load shedding and rotating outages for residents. GPA issued a precautionary notice this week for potential one-hour rotating outages through Sunday due to limited capacity. It’s intended to help residents plan for outages, although the outage won’t necessarily occur.
A main generator, Cabras 2, tripped offline July 28 due to a boiler tube leak, and repair work is expected to be completed this week. Meanwhile, another major generator, the Yigo Combustion Turbine, remains offline for repairs and is expected to remain offline for a few months.
Utility scale solar power plants help power the island during the day, but it’s at night, from around 6 to 10, when demand peaks.
“Utility scale solar plus conventional units has allowed us to continue services through the daytime, has allowed us to service other units in the daytime. But when it comes to peak … we don’t have the adequate reserve, most especially these past several days,” GPA General Manager John Benavente said during an oversight hearing Tuesday, which included discussions on load shedding.
The island experienced some substantial load shedding Monday night when GPA’s capacity went down to 189 megawatts as two combustion turbine units failed and were in need of repair, according to Benavente. Around peak time, Guam was short nearly 30 MW from demand. The turbines came back online before 11 p.m. Monday.
By Tuesday, about 211 MW of capacity was available. When Cabras 2 comes back online, the island’s generation capacity will go up another 35 MW. With some additional capacity gained from a couple of other generators, the island’s total capacity is targeted to be around 261 MW by Saturday.
“As you can see, when we have 261 MW we really don’t have the load shedding. Unless we start losing more base load (generators) and most especially when we lose two units for whatever reason,” Benavente said Tuesday.
GPA is also working to restore about 64 MW of capacity among various generators by Oct. 31. That includes bringing back the 20-MW Yigo CT.
The power utility also needs to find ways to boost or maintain capacity with the expected delay in the commissioning of the Ukudu power plant, the 198-MW facility that will serve as a main power source for Guam. Typhoon Mawar damaged storage tanks at the plant site, and the project may not be completed until the end of 2025.
Benavente is anticipating that Guam’s peak demand will grow to about 275 MW between 2024 and 2025.
“This shows the most critical period of time is between now and when Ukudu (power plant) is completed,” Benavente said.
The head of GPA anticipates providing definitive recommendations for effectively increasing capacity in time for the August meeting of the Consolidated Commission on Utilities, the governing board for the power and water utilities.
GPA wants to award a program management contract for the 40-MW Yigo diesel plant, which is currently capable of only eight MW, and for other power plants to increase their capacity as well. The utility is working with Sens. William Parkinson and Sabina Perez to improve the procurement and appeals process in favor of critical government projects, according to Benavente, who has spoken about how protests have hurt the utility’s efforts to meet generation goals.
Benavente said he will also ask large load customers, such as hotels and large businesses, to participate in an interruptible load program. In this program, large power consumers would use their own generators during peak times.
However, Benavente said, there were very few takers last year because those customers had issues with their generator systems. Efforts for the interruptible load program would also include engaging government entities and the military.
GPA may also seek to bring in temporary power for a three-year period.
“We’re trying to figure out the cost of this, where it might be, what is the capacity range. And I hope we can make a decision on this and bring it to the August (CCU) meeting. Again, all of this is going to cost some funding, so I’m going to figure that out as to how we’re going to do this,” Benavente said Tuesday.
GPA is also looking at the possibility of utilizing energy storage batteries so that stored solar energy can be used during peak hours at night.
“We already have been working on a utility sized energy storage system to allow us to shave peak and to shift, catch that energy in the daytime and not require thousands of batteries on the island. Let GPA be the battery of the island. … It’s in the works but something that we have to see whether we can expedite,” Benavente said, adding that issues will keep recurring unless solutions can be found to bring up the island’s reserve capacity.
Guam Power Authority General Manager John Benavente addresses the Consolidated Commission on Utilities board of trustees Wednesday, April 26, 2023.
