(Photo: Repairs to Puerto Rico’s grid under way in January 2018. Credit: Jeff Miller, Western Area Power, Flickr Creative Commons)[/caption]
Puerto Rico Electric Power Authority (PREPA) published a new plan that makes recommendations and analysis for the utility’s energy supply resources over the next 20 years. Prepared by energy strategic and technical consultants from Siemens Power Technologies International, the Integrated Resource Plan centers around electrical islands called MiniGrids.
These “zones of resiliency” can be segregated during and after a major weather event, according to the Integrated Resource Plan (IRP). The plan calls for modernizing the transmission and distribution grid so that it can be segregated into eight largely self-sufficient MiniGrids.
“The recommended MiniGrids are designed to operate in grid-isolated mode following a major storm or other disruptive event,” the report says. “MiniGrids are regions of the system that are interconnected with the rest of the electric power system via lines that may take over a month to recover after a major event, and should be able to operate largely independently, with minimum disruption for the extended period of time that would take to recover full interconnection.”
Besides the eight electrical islands, the IRP says that smaller microgrids will be located within some of the MiniGrids in areas likely to remain isolated for longer stretches of time owing to their geography.
However, as Microgrid Knowledge’s Elisa Wood pointed out this week, PREPA hasn’t embraced the government’s 2018 rules about microgrids intended to boost development, define types of generation, and clarify municipality and utility roles. Nor has PREPA created a microgrid interconnection process, Agustín Carbó, a former chairman of the Puerto Rico Energy Bureau who now works as a senior manager at the Environmental Defense Fund, told the outlet.
For the 20-year study period covered in the IRP, the net present value of all operating costs is $14.1 billion, the report says.
“The business case for transforming the grid architecture is straightforward: it provides the least cost approach to achieve resilience against major hurricanes, meet and exceed compliance with the renewable portfolio standard, engage customers, and lower cost,” the Siemens report said.
Late last year, regulators in Puerto Rico introduced a bill calling for the island to get 100% of its electricity from renewable sources by 2050. PREPA’s plan envisions increased reliance on renewables, including adding 1.38 GW of solar photovoltaic generation as well as 920 MW of battery storage from 2019 to 2022.
“There are many uncertainties in Puerto Rico’s and PREPA’s future which can be change the trajectory of the IRP decisions over time,” the plan said. “What is certain is the urgent need to rebuild the system based on a MiniGrid architecture as soon as possible.”
PREPA filed for bankruptcy in July 2017, before Hurricane Maria hit. Then the nearly Category 5 storm razed Puerto Rico’s infrastructure in September 2017, taking the US territory’s entire electrical grid down.
In April 2018, the island went through another blackout that affected more than 1.4 million PREPA customers when an excavator accidentally downed a transmission line. When July rolled around, many customers were still without power and the utility’s leadership was in flux.
After PREPA provides testimony about their 300-plus-page Integrated Resource Plan today, the Puerto Rico Energy Bureau will rule whether to proceed with it, or ask the utility for more revisions, Wood reported.
