Final IRP Proposal for Puerto Rico Calls for ‘Mini-Grids’ and Rapid Solar and Storage Deployment

The Puerto Rico Electric Power Authority (PREPA) this week filed a final draft of its 2019 to 2038 Integrated Resource Plan (IRP), which calls for big deployments of solar and storage and a system of eight, distributed “mini-grids” to support the island during disasters.

The plan, drafted by Siemens, closely mirrors a draft released in January. While relying heavily on a build-out of clean energy resources, especially in the first four years of the plan, the IRP also includes investments in natural gas infrastructure.

Siemens analyzed nearly 80 pathways for the island’s future energy system, but ultimately settled on a hybrid of two scenarios “deemed both low cost and most practicable,” with a $9 million difference in cost. The Siemens recommendations rely on the “energy modernization scenario” with add-ons from the second scenario. Estimated costs for the energy modernization scenario ring up at about $15.2 billion.

Unlike traditional IRPs, which usually emphasize low-cost and reliability, Siemens noted that PREPA’s plan needed to fulfill five pillars adopted in February of last year. They require that the IRP center the customer, minimize cost, focus on resiliency, incorporate a transition to renewables and bring employment and economic growth to the island.

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Because of the natural gas infrastructure incorporated into the final plan, clean energy advocates won’t be completely satisfied. But renewables boosters did get some of what they asked for.

The plan to divide the island into eight “mini-grids” echoes calls for a more distributed system in cases of future extreme weather. In the plan, Siemens said the grids were designed to operate independently during major storms, allowing service to continue to critical loads.

The system would also add smaller microgrids in areas where the landscape makes repairs difficult. After Hurricane Maria, many areas of the island, especially in its mountainous middle, were without power for months on end. Helicopters were required to do repairs in areas with challenging terrain.

In the first four years of the plan, Siemens also called for the buildout of between 720 and 1,200 megawatts of solar and between 440 and 900 megawatts of energy storage. For reference, California, the country’s largest state solar market, installed 2,168 megawatts of solar between 2014 and 2017, according to data from Wood Mackenzie Power & Renewables. In that same timeframe, the entire U.S. installed just over 545 megawatts of storage.

The IRP also recommended that request for proposals for those resources be combined, so bidders can offer to provide either or both of the technologies.

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Alongside that progressive solar and storage vision, Siemens also recommended a variety of natural gas infrastructure, which is likely to draw ire from clean energy advocates. Ahead of the release of the final plan, environmental group El Puente Enlace Latino de Acción Climática said the document was “full of contradictions” and would “crucify Puerto Rico with natural gas.”

The group also said the proposed plan jeopardized the island’s renewable portfolio standard (RPS) target. Under the final Siemens plan, Puerto Rico would have an RPS of just 24 percent by 2038. The island’s current RPS is 20 percent by 2035 — which it is not on track to meet — but the island’s government is considering a target of 100 percent renewables by 2050.

Siemens recommended the addition of at least three 302-megawatt combined cycle gas turbines and three smaller 38-megawatt combined cycle turbines. The IRP also called for 18 “mobile gas turbine peaking units” at 23 megawatts each to be distributed at five locations around the island. A new liquid natural gas terminal in San Juan plus two ship-based terminals in Yabucoa and Mayagüez would supply the sites.

Though Siemens placed the buildout of solar and storage on an accelerated timeline, it estimated new natural gas infrastructure could be added around 2025.

More than half of renewable energy sources are devoted to producing electricity.

Next up for the plan is an okay from the island’s energy bureau, after a 30-day period in which it will decide whether PREPA’s plan is complete.