Case Study: Rooftop Solar Potential Analysis for Orlando Utilities Commission

NREL analysts customized the Distributed Generation Market Demand (dGen™) Model for the Orlando Utilities Commission (OUC), helping to better understand the city's rooftop solar potential.

Problem: Rooftop Solar Adoption Has Been Slow in Orlando

Orlando, Florida, has committed to 100% clean energy by 2050, but adoption of rooftop solar adoption has been slow compared with early adopters such as California.

Deployment of customer-adopted solar and energy storage technologies could contribute significantly to reaching the city's goal. Orlando energy planners want to understand the potential for customer-owned solar to meet energy goals and plan future power systems.

Solution: Customized Demand Forecasting

NREL and the OUC partnered to customize the model in a novel way. They individually simulated solar adoption potential for every building in the OUC service territory through the year 2050.

An agent was designated for each building and fell into three categories: those who do not find it economic to adopt solar, those who can adopt a system that offsets some of their consumption, and those who can adopt solar that offsets 100% of their annual consumption. The agents also included socio-demographic attributes of the building occupants and factored in decision-making peer effects, or the influence of solar adoption by neighbors.

dGen then individually modeled agents in scenarios with different costs of solar and tariff structures through the year 2050 to see if they would choose to adopt solar. The resulting adoption potential was mapped to distribution feeders.

Impact: Improved Understanding of Rooftop Solar's Role in Future Orlando Energy Systems

dGen shows substantial potential for rooftop solar photovoltaic (PV) adoption in single-family homes in the OUC service territory—248 megawatts (MW) projected by 2030 and 370 MW by 2050. Renter-occupied and multifamily homes, which traditionally have lower adoption rates, also have substantial potential and could increase the overall projection to 355 MW by 2030 and 585 MW in 2050 if they were to adopt at levels similar to owner-occupied buildings.

Twenty-five percent of all projected adoption through 2050 is concentrated on just 5% of distribution feeders and 88% of projected adoption on 50% of feeders—the highest-resolution solar projections to date for the OUC.

The payback period for the rooftop solar PV systems varies, according to model results, but is largely driven by solar costs and changes to solar valuation by OUC as well as the expiration of the Federal Investment Tax Credit. By 2030, most residential systems are profitable after 8 years.

Across all scenarios, much of the growth in rooftop solar adoption is projected to occur by 2035, and adoption is sensitive to both rate reform and lower PV costs. Although a lower cost of PV significantly increases the amount of adoption by 2030 and 2050, adoption also decreases by a similar degree with tariff reform that replaces net metering with net billing and introduces residential time-of-use rates.

With dGen detailed insights, Orlando energy planners now know where exactly to focus grid infrastructure efforts.