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Puerto Rico’s utility calls for making the island into eight minigrids

  • 5 months ago (2019-02-06)
  • David Flin
Distribution 43 Latin America 25 Transmission 67

The Puerto Rico Electric Power Authority (PREPA) has issued a draft integrated resource plan (IRP) that calls for segmenting the island’s electrical grid into eight minigrids, along with myriad microgrids, and installing more energy storage than is currently available in the USA. PREPA plans to submit the plan to regulators on 12 February. The IRP was prepared for PREPA by Siemens Power Technology.

The IRP focuses on reshaping the island’s grid to decentralise power production and deliver it through independent blocks, in order to help avoid the massive power outages caused by Hurricane Maria in 2017. The eight connected minigrids would be able to operate independently when required. The minigrids would be sited to support clusters of critical transmission and distribution voltage loads, downstream of distribution and transmission vulnerabilities.

The IRP also calls for smaller microgrids within the minigrids. Microgrids would also be built in remote areas of Puerto Rico not easily reached by transmission lines or suitable for a minigrid. Several microgrids have already been built on the island by private companies and government since the hurricane.

In addition, under the plan, Puerto Rico would add 750-1200 MW of solar power. PREPA would issue competitive solicitations in 250 MW blocks. PREPA would also install 500-1100 MW of battery energy storage over four years.

In preparation for the high level of distributed energy added to the system, PREPA would reinforce and upgrade its distribution system to enable two-way flow of energy and provide voltage regulation and flicker control.

The plan also includes 17-18 small natural gas-fired generators each of about 23 MW. PREPA said that these are necessary to maintain the minigrids should a hurricane force the minigrids to operate independently for a month or more. The island would retire most of its fossil fuel plants by 2025, but would keep operating two combined cycle gas-fired plants in San Juan and Aguirre and gas turbines in Mayagüez and Cambalache. The island would also build two LNG terminals.