Exploring the Benefits of Distributed Solar in Rhode Island

The electric utility industry is in the midst of a fundamental transformation as it prepares for a distributed energy future. Key to unlocking this future is a better understanding of the costs and benefits of distributed generation and its ability to reduce peak loads on the electric distribution system. To this end, the Rhode Island Office of Energy Resources (RI OER) developed a pilot project to explore how distributed solar could provide value to Rhode Island’s electric grid. The pilot project, initiated in 2014, has successfully mobilized the local community to adopt solar PV beyond initial expectations, helped to defer traditional utility capital investments, and provided important lessons for the consideration of “non-wires alternatives” in distribution system planning. Preliminary estimates indicate that solar resources that were geo-targeted by the project could provide enough peak load reduction to defer the construction of an expensive new sub-station feeder by two to four years.

Using Distributed Generation to Address Electric Load Constraints

For several years, National Grid, Rhode Island’s major electric utility, used an initiative called DemandLinkTM to geo-target customer adoption of energy efficiency and demand response to address a localized electric load constraint during late summer afternoons in the towns of Tiverton and Little Compton. In order to understand how solar might also help contribute to meeting the distribution need, RI OER proposed using an additional non-wires alternative: geo-targeted solar PV deployment. The System Reliability Procurement Solar Distributed Generation (SRP DG) Pilot Project aimed to use solar adoption to help defer the construction of a new substation feeder in the Tiverton-Little Compton area. It employed two key solar-adoption strategies: (1) an open solicitation for competitive proposals from solar developers and (2) a locally based Solarize campaign.

Solar Solicitation

RI OER designed the pilot project’s solar solicitation to fully integrate with and complement the state’s Renewable Energy Growth (REG) Program, which helps Rhode Island customers develop and benefit from renewable energy projects by using fixed-price, long-term, performance-based incentives. RI OER offered a competitive grant opportunity to REG Program participants based on the incremental costs that might be incurred to maximize a solar installation’s benefit to the distribution system. One developer submitted a proposal for a single-axis tracking system. The solar tracking system design helps maximize value to the distribution grid by providing increased electric generation during the late afternoon load peak when the area’s load constraint is most acute.

Solarize with a Twist

Solarize initiatives use community engagement techniques and competitive tiered pricing to promote targeted adoption of solar while driving down costs for all participants by leveraging economies of scale. The Solarize Rhode Island component of the SRP DG project brought together multiple collaborators, including the Renewable Energy Fund at Commerce RI, SmartPower, a non-profit marketing company, and RI OER. RI OER added a new twist to the traditional Solarize tiered pricing model for the Tiverton and Little Compton campaigns: a sliding-scale of incentives for westward-facing solar projects, which were based on the solar project’s incremental value to the distribution system during the local summer peak periods. Recognizing that solar panels facing west and southwest would generate electricity during the critical time of peak demand when the value to the grid is highest, the Solarize campaigns in Tiverton and Little Compton offered extra monetary incentives to homeowners who oriented their solar systems westward, to offset their lower overall solar production. Sixty-seven Rhode Island customers signed contracts for solar during the course of the Tiverton and Little Compton Solarize campaigns. Many received the added incentive for westward-facing solar installations.

Leadership, Lessons, and Legacy

The RI OER’s SRP DG project represents a successful geo-targeted effort to promote customer adoption of solar. Collectively, the project enrolled 735 kW of solar DG, exceeding its original goal of 520 kW. Not only did the project result in substantial new installed solar capacity, but it also achieved cost savings for residents of Tiverton and Little Compton, as well as for statewide rate-payers. The addition of solar is anticipated to contribute to the deferral of a proposed new substation feeder. National Grid estimates that the solar enrolled through the project will contribute 362 kW of projected peak load reduction. Beyond the immediate savings and increased solar penetration achieved, the project offers a real-world demonstration of the strategic integration of distributed solar deployment with electric distribution planning. The project provides an example of a successful partnership between a state energy office and an electric distribution company, and the use of geo-targeted solar as a viable “non-wires solution” to address localized electric load constraints. It provides a replicable model that other states can use to strengthen cooperative planning with utilities on distributed generation.

PROGRAM HIGHLIGHTS

• The System Reliability Procurement Solar Distributed Generation Pilot Project demonstrated how distributed solar PV can provide value to RI’s electric gird.

• National Grid estimates that the project will contribute 362 kW of projected peak load reduction, demonstrating a viable “non-wires alternative” in distribution system planning, and potentially deferring a new substation feeder by an estimated two to four years.

• The project was a constructive collaboration between a utility, state agencies, and key energy stakeholders to advance knowledge of solar distributed generation through a real-world demonstration of its strategic integration with the electric grid.

Rhode Island’s System Reliability Procurement Solar Distributed Generation Pilot Project was a recipient of a 2016 “State Leadership in Clean Energy Award,” presented by the Clean Energy States Alliance (CESA).

CESA hosted a webinar highlighting Rhode Island’s System Reliability Procurement Solar Distributed Generation Pilot Project on July 13, 2016.

This blog post was also published in Renewable Energy World.