NREL Helps Puerto Rico Plan for 100% Renewable Energy

By Christian Roselund

The U.S. Department of Energy’s National Renewable Energy Laboratories (NREL) has produced its second progress report in a 2-year effort to analyze pathways for the island territory to meet 100% of its electricity demand from renewable sources. The PR100 One-Year Progress Summary report reflects the mandate set in Puerto Rico’s Energy Policy Public Act that the territory reach 100% renewables in its electricity supply by 2050, with interim goals of 40% by 2025 and 60% by 2040.

A major theme in the report is the split between distributed and utility-scale solar. NREL’s modeling shows that if agricultural land, buildings, urban areas, rivers, and conservation areas are excluded, Puerto Rico does not have enough land to meet its targets with utility-scale solar and land-based wind. This means that some combination of the use of PV on brownfields and/or agricultural land, floating PV, and/or distributed rooftop solar is necessary.

Distributed rooftop solar is already popular in Puerto Rico, largely as a means to increase the resilience and reliability of electricity, particularly in the aftermath of hurricanes. In the report, NREL models deployment of between 3 and 7 gigawatts of distributed solar in four different scenarios. These range from the “economic” scenario in which distributed energy is deployed based on financial savings to building owners to the “maximum” scenario in which distributed solar is deployed on every suitable rooftop. The report finds that even in the economic scenario distributed solar increases 6x by 2050. Notably, the report does not look at the grid upgrades needed to support this massive expansion of rooftop PV, or external challenges that could limit deployment such as supply
chain issues.

The report also makes an important resilience argument for expanded deployment of distributed solar, finding that the modeled future system with smaller renewable energy projects spread across the bulk electric grid tends to recover power faster than the current system. NREL also found that the deployment of advanced inverters with black-start capability to accompany this distributed energy can reduce recover time following hurricane-driven outages by up to 3x.

NREL has now begun year 2 of the study. For this phase the organization is looking at issues including the impact of the modeled scenarios on the transmission system, the impact of adding high levels of distributed energy to the distribution grid, and the use of microgrids for enhanced resilience. It will also look at potential impact on electricity rates.

Source: Puerto Rico Grid Resilience and Transitions to 100% Renewable Energy Study
(PR100) (DOE)