Following back-to-back hurricanes in 2017, Puerto Rico saw nearly 80% of its power grid destroyed. In 2019, the territory passed Act 17, which committed to achieving 100% renewable energy by 2050. New analysis from the National Renewable Energy Laboratory (NREL) shows that this goal is like attainable.

The Puerto Rico Grid Resilience and Transitions to 100% Renewable Energy Study (PR100) is a two-year study — led by the U.S. Department of Energy’s Grid Deployment Office with funding from the Federal Emergency Management Agency — that leveraged and integrated dozens of models and analyses from researchers across six DOE national laboratories: the National Renewable Energy Laboratory (which led the study), along with Argonne National Laboratory, Lawrence Berkeley National Laboratory, Oak Ridge National Laboratory, Pacific Northwest National Laboratory, and Sandia National Laboratories.

“We live in remarkably challenging times. It is collaborative efforts such as PR100 that show NREL answering those challenges in inspiring ways,” said NREL Director Martin Keller. “What I find exhilarating about the PR100 study is that it validates NREL’s approach to such all-encompassing community visions—it is a result of our extensive dialogue with the people who will bring these ideas to life.”

NREL researchers and the project team worked with an advisory group during the first six months of the study to define scenarios to model based on the stakeholder priorities:

“We needed to know what changes to the transmission and distribution grid infrastructure would be needed to achieve 100% renewable energy, with significant adoption of residential rooftop solar paired with battery energy storage,” said NREL’s Murali Baggu, the study’s co-principal investigator. “So, we explored a mix of solar photovoltaics, battery energy storage, wind energy, other renewable generation and infrastructure evolution options—both at the grid scale and for individual buildings—that is most achievable, cost-effective, and resilient against disruptions.”

Three scenarios

Three possible scenarios were identified by the PR100 team as viable for a future energy system that is resilient for the most remote communities, obliging of land-use interests, and supportive of distributed and local ownership.

“The level of Puerto Rico’s reliance on distributed energy generation will affect policy and investment strategy over the coming years,” said Nate Blair, NREL’s PR100 technical lead. “Exploring the implications of various levels of distributed generation—through scenarios—helps answer questions about trade-offs and possible outcomes.”

Six national laboratory models were used in concert to produce each scenario, including NREL’s dGen and Engage (capacity expansion), PRAS (resource adequacy), and SIENNA (production cost) tools.

Scenario 1 — Economic

Researchers used NREL’s dGen model to calculate the likely adoption of distributed solar and storage based on the financial savings and value of backup power to building owners and prioritized for critical services (circled) through installation and use of distributed energy resources.

Credit: NREL

Scenario 2 — Equitable

Rooftop solar and storage adoption was expanded beyond Scenario 1 to include remote and low- and moderate-income households.

Credit: NREL

Scenario 2 modeled remote municipalities, building on Scenario 1 by expanding the number of rooftop solar and storage systems deployed to very low-income households and households in remote areas. Households earning 0%–30% of area median income were considered to be low-income. Remote areas can be defined by outage duration after a major disruption such as Hurricane Maria, typical outage durations in the absence of a storm or other disruptive event, and other outage metrics.

Credit: NREL

Scenario 3 — Maximum

Rooftop solar and storage is added to all suitable rooftops to meet critical loads. This deploys enough rooftop solar and storage to meet the critical loads for all buildings, resulting in extensive deployment across Puerto Rico, NREL said.

Credit: NREL

For each of these scenarios, four variations were created based on land usage and energy loads, resulting in 12 total scenarios for stakeholder consideration. Two land-use variations — “less land,” and “more land” —were defined to assess developable area for utility-scale solar and wind, based on input that preservation of agricultural land is a high priority. Both variations exclude roadways, water bodies, protected habitats, flood risk areas, slopes greater than 10%, and agricultural reserves from developable area; “less land” also excludes agricultural land defined by the 2015 Puerto Rico Land Use Plan.

Due to the uncertainty around electric load (demand) projections, two electric-load variations were defined: “mid case” and “stress.” The “stress” variation increases over time, capturing uncertainty if loads do not decrease and ensuring decision makers do not under plan.

System upgrades and investments

PR100 contains one main conclusion: While it is technically feasible for Puerto Rico to transition to 100% renewable energy by 2050, significant system upgrades and investments — guided by community participation — are needed.

The current power system is fragile and has been underperforming and under invested, NREL said, and correcting the situation will require infrastructure and operational improvements no matter which path is chosen.

Next steps

PR100 study results show that Puerto Rico has enough renewable energy resource potential to meet its electricity demand, now and through 2050. Reaching 100% renewable energy is possible and can be achieved with mature technologies and all fossil-fueled plants retired. Regardless of scenario, there are concrete factors that utility and grid operators, renewable developers, and energy regulators will face.

There is an immediate need to increase capacity to accommodate renewables, NREL said, and the transmission and distribution grid infrastructure needs system upgrades. Utility-scale solar generation is a necessity to ensure demand can be met reliably, even if every suitable rooftop also has solar generation. Generation and storage resources should be spread across more locations to improve the system’s ability to recover from disruptions. When hurricanes hit the grid, all energy system resources—including distributed and utility-scale renewables and energy storage—should participate in the recovery process.

The team also created an implementation roadmap with considerations for how Puerto Rico can reach its objectives.

Originally published in Renewable Energy World.

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