HAGÅTÑA (The Guam Daily Post) — The Guam Power Authority has a plan to address the current generation capacity shortfall on Guam over the next six to nine months. This includes reducing customer demand through an interruptible load program; increasing capacity by repairing generators; pursuing temporary power if it is feasible and can be fast-tracked; and pursuing energy storage systems so solar power or conventional energy can be stored during the day and be used during peak demand times in the evening.
Guam residents recently have been experiencing rotating outages due to load shedding, which is how the power utility attempts to maintain grid stability and services when the demand for energy exceeds the capacity to generate power.
Not only have generators gone offline for periods of time due to emergency issues, but the 20-megawatt Yigo Combustion Turbine will remain unavailable for some months as it undergoes repairs after incurring damage by Typhoon Mawar.
The Cabras 1 and 2 baseload units were both down late last week, and GPA released a notice Sunday informing customers of potential rotating outages lasting up to Wednesday. Cabras 2 is expected to come back online sometime this week.
Cabras 1 was back by around 2 a.m. Monday, and that served to limit load shedding to only three feeders for about 30 minutes Monday night, according to the power utility. However, as recent weeks have shown, the situation for the island’s energy capacity can change quickly.
Ukudu timeline
As baseload units, Cabras 1 and 2 serve as two of the main generators that power Guam. But the units are now decades old, experience various issues and are set to be decommissioned. Before that can happen, the new 198-megawatt power plant being built at Ukudu needs to come online, as there isn’t enough generation capacity on Guam to retire the Cabras units until then, GPA has reported. Unfortunately, the completion of the Ukudu project will be delayed because of damage to storage tanks sustained during the typhoon.
Before Mawar, the Ukudu plant was set to be commissioned by April 2024.
At a Tuesday work session with the Consolidated Commission on Utilities, GPA General Manager John Benavente said Ukudu power plant officials have shifted their timeline to January 2026.
“We are going to have some discussions on how, first of all, whether we agree with that schedule; and secondly, how we can expedite that schedule,” Benavente said. “I hope maybe by the September meeting I will have some more information on that.”The delay places more emphasis on maintaining Cabras 1 and 2, as well as other existing units, in the meantime. Currently, if one baseload generator goes down, generation capacity falls to about 10 megawatts short of peak demand. Two baseload generators down would leave the island 53 megawatts short, GPA has said.
Yigo CT is expected to remain down until November or December, according to discussions Tuesday. Once it does come back, one baseload generator down would still leave 23 megawatts of reserve capacity. But two baseloads going down would leave Guam 20 megawatts short of the anticipated peak.
GPA also is hoping to increase capacity output for other units, although the utility is experiencing some procurement protests on this issue.
Interruptible load program, other options
In the more immediate term, the power utility also hopes to expand participation in the interruptible load program. Under this program, power customers utilize their own generators to mitigate demand on the grid in exchange for credits.
GPA currently has three interruptible load partners: the Guam International Airport Authority, the Port Authority of Guam, and Guam Regional Medical City. These entities represent nearly 4 megawatts that can be subtracted from the island’s energy demand, or power for nearly 2,000 residential customers, based on 500 residential customers for each megawatt, according to discussions Tuesday.
About 6.6 megawatts can be taken out of the demand by shifting Guam Waterworks Authority assets to generator power.
The power utility sent out invitation letters Monday to about 187 large power customers, requesting participation in the program. GPA also is requesting capacity and interruptible load support from the military.
GPA is preparing to launch an outreach program asking customers to help reduce load shedding with actionable energy conservation measures, such as shutting off water heaters during peak hours and shutting off more air conditioners during emergency load shedding periods; and for government entities to place their air-conditioner thermostats at 75 degrees Fahrenheit or higher, and to turn off air conditioners when possible.
For temporary or long-term reserve capacity, adding 40 megawatts of new generation capacity to Guam would cost upward of $80 million, which GPA does not have. The utility is looking at pursuing funding from federal agencies or other entities, as well as looking into how much it will cost to lease temporary power for up to five years, assuming it is feasible and can be fast-tracked.
GPA is working to pursue a 45-MW energy storage system, but it would take up to 18 months to bring the system online, according to Benavente.
General Manager John Benavente of the Guam Power Authority gives a report to the Consolidated Commission on Utilities during a work session Tuesday, Aug. 22, 2023, at the Gloria B. Nelson Public Service Building in Mangilao.
