Eversource, United Illuminating urge on-site focus and performance-based storage in PURA successor tariff

Eversource Energy and United Illuminating told the Public Utilities Regulatory Authority at a Sept. 24 technical meeting that successor renewable energy tariffs should remain focused on on‑site generation sized to a customer’s load and use performance‑based mechanisms to encourage energy storage, rather than flat adders that could shift costs to nonparticipating ratepayers.

The recommendation was made during PURA’s technical meeting in docket 250214. Eversource’s director of customer solar programs, Brian Rice, and Katarina Miller, manager of electric supply for United Illuminating, presented joint written comments and an attached analysis showing customers could still realize significant bill reductions under alternative tariff designs that do not provide full retail credit for excess generation.

Rice and Miller said their analysis—shared with PURA and stakeholders in an Excel workbook—showed representative residential customers could save roughly $1,500 to $2,500 per year under some alternative scenarios. Rice reiterated the companies’ view that distinguishing compensation for energy exported to the grid from retail rates would create an incentive for customers to add storage and to manage discharge timing to better align with consumption.

Why it matters: PURA is conducting a successor study for Connecticut’s renewable energy tariff programs as required by the General Assembly. Changes to how exported energy is credited and how paired storage is compensated could shift program costs among participants and nonparticipants and affect adoption of on‑site solar and storage.

Key points from the EDC presentations

- On tariff economics, Rice said the EDCs’ modeling focused on PV-only generation profiles but that weighted average values of on‑site consumption plus differentiated export compensation could still produce values (he cited approximately 18¢/kWh in some scenarios) consistent with some PPA and lease rates. He also offered to supplement the analysis to show paired solar plus storage impacts if PURA requested additional assumptions.

- On low‑income customers, Rice described how current netting tariffs operate for a low‑income discount rate (LIDR) customer in Eversource’s example: the billing example used a retail export credit of 27.7¢/kWh for a billing period that produced a $95 bill credit on 344 kWh of net excess generation; a 50% customer‑charge discount and accounting of remaining credit ($90.63 in the example) were explained. Eversource and UI emphasized they operate several affordability programs—LIDR, a matching payment program for arrears, home energy solutions for income‑eligible customers, and a Shared Clean Energy Facility (SCAF) mechanism that prioritizes eligible customers—and noted that installing on‑site generation may not be the best option for every household.

- On nonresidential paired storage, Miller said paired storage can reduce peak demand and support reliability and recommended enabling dual participation of paired resources across programs (for example, flexible interconnection, non‑wire alternatives, wholesale opportunities under the Wholesale Distribution Access Tariff, and demand‑rate structures) rather than using a simple storage adder. She cautioned that adders that are not closely tied to performance can be inefficient and shift costs to nonparticipants.

- On community solar and shared‑benefit programs, the EDCs told PURA that existing programs (SCAF, virtual net metering channels for multifamily and affordable housing, and other shared‑solar pathways) already prioritize low‑income customers in practice. Eversource reported that, across its portfolio, nearly 90% of the SCF/SCAF participants were low‑income customers, and UI reported 50–70% participation by low‑income customers in its territory.

Questions from PURA staff and stakeholders

- PURA staff (Molly Charles and Chris Arpin) asked whether the EDC analysis could be supplemented to show bill savings with paired solar and storage; Rice said the EDCs could provide that analysis but would need to state assumptions about storage operation. Staff also asked for clarification about whether the value of on‑site solar used by LIDR customers is treated differently between the two utilities; Rice and Miller said the customer bill experience appears similar but that accounting treatments on the back end may differ and that the companies would consider a supplemental filing to clarify any differences and impacts on nonparticipating ratepayers.

- The EDCs acknowledged the need for clear metering guidelines for paired storage, suggested the interconnection working group as the appropriate forum, and described metering configurations used in prior programs (for example, ARES) that allow default front‑of‑meter operation with switching capability to provide backup in outage conditions.

- Stakeholders pressed on storage adders, pointing to Massachusetts’ SMART program experience. Rice and Miller said Massachusetts includes explicit adders for storage in SMART but that the program’s operational requirements and price‑setting mechanisms have proved challenging to ensure adders deliver commensurate system value, and EDCs therefore favor tying compensation to measured performance across programs instead of a broad adder in a renewable tariff.

EDC cautions and operational concerns

Both Eversource and UI urged caution in designs that would treat exported power to the grid as a uniform retail product or that would extend retail‑level compensation to projects that primarily supply wholesale grid power. Rice said those kinds of designs raise cost‑allocation concerns because compensation not tied to customers’ bills can increase program costs for nonparticipants; for projects intended to supply grid power, he suggested competitive solicitation and compensation tied to avoided wholesale costs.

The EDCs also emphasized the importance of flexible interconnection and non‑wire solutions as mechanisms to recognize storage value (for example, reducing interconnection upgrade costs by limiting maximum export) and noted existing programs—Connected Solutions, Energy Storage Solutions, and a Wholesale Distribution Access Tariff (WAT)—that can be used to capture performance‑based value.

What the meeting did not decide

PURA staff and stakeholders sought supplemental information, but no formal policy changes or votes were taken at the technical meeting. The EDCs committed to consider supplying additional analyses on paired solar-plus‑storage and to discuss metering guidance with stakeholder working groups.

Next steps

PURA will continue to develop the record for its statutory report. Staff noted a third set of interrogatories is scheduled and that parties should expect additional data requests; PURA recorded that the next set of interrogatories is due Oct. 29 in docket 250214.