The Rhode Island Public Utilities Commission on Jan. 2 said that it will accept comments through 4 p.m., on Jan. 30 on its “Investigation into the Treatment of Storage as an Electric Distribution System Resource.”
The docket (Docket No. 5000) will include these topics, the commission said:
- Identification of the costs and value streams of distributed energy resources under each of the programs in which renewable energy distributed energy resources can currently participate
- Identification of the costs and value streams of distributed energy resources paired with storage under each of the programs in which renewable energy distributed energy resources can currently participate
- Understanding whether and how the design and purpose of a paired system changes the costs and value streams
- Identification of a definition of inappropriate market activity
- Understanding of concerns with time-of-use rates and implications on the previously identified costs and value streams
- Ownership of capacity and ancillary services values
The commission said that commenters should list each proposed topic together with an explanation of any problem that currently exists that needs to be solved, whether the proposed topic is a short-term or long-term priority, and whether there are any related dockets or issues that would be affected by the proposed topic. If the proposed topic has been addressed by any other New England regulatory body or legislature, or by the New York State Public Service Commission, then the commenter should also advise the commission and provide any relevant citations.
The commission added that it will finalize the scope of the docket and the appropriate process after a review and consideration of proposals received in response to the Jan. 2 notice.
As noted in a Dec. 23, 2019, order, the Episcopal Diocese of Rhode Island — referred to as the petitioner — in October 2019 filed with the commission a petition for declaratory judgment seeking a declaration that renewable energy generating systems paired with storage on systems in excess of 25 kW alternating current (AC), where the battery storage charges only from the renewable power generation system, where the customer/host does not take electric supply under a time-varying or time-of-use rate, and where the generator does not claim the right to capacity payments or the value of ancillary services, are eligible net metering systems.
The petitioner also requested that the commission open a separate proceeding to address net-metering eligibility and treatment of systems under different system configurations, use-cases, sizes, and rate structures, as well as to include consideration of capacity and ancillary service values and ownership.
The petitioner noted that in Docket No. 4743, the commission declared that “Solar power generating systems no greater than 25 kW AC, and paired with battery storage, where the battery is only charged from the solar power generation system, and the host is not on time-of-use rates, falls within the definition of an eligible net metering system.”
The commission added that the petitioner asserted that regardless of the size of the system, a solar-paired-with-storage system is a net metering facility. The petitioner noted that newer inverter technology on solar facilities disables battery charging from the grid and allows charging to occur only when there is power available from the energy generating facility. The commission added that the petitioner recognized that that configuration would be necessary to allow the combined system to fit within the definition of eligible net metering system. Thus, the petitioner reiterated its request that the commission find renewable generating systems paired with storage that only charge from the renewable energy generation resource and discharge to the grid eligible for net metering as long as they have control measures in place to prevent charging from the electric grid.
Comments were received from Narragansett Electric Company d/b/a National Grid, the state Division of Public Utilities and Carriers (Division), and the state Office of Energy Resources, the commission said, adding that the Division, for instance, recommended approving the petition with certain conditions, including that the solar power generating system is greater than 25 kW and that the battery storage system only charges from the solar generating system.
The commission noted that at a Dec. 17, 2019, open meeting, it reviewed the filings, as well as the relevant law, and declared that a renewable energy power generating system paired with battery storage falls within the definition of an eligible net metering system when:
- The battery is only charged from the solar power generation system
- The host is not on time-of-use rates
- The generator/customer does not claim the right to capacity payments or the value of ancillary services markets
- The entire system — renewable energy power generating system + storage — is paired on the customer side of the retail meter
The commission said that it also provided that National Grid is to have the right to inspect the paired system to ensure that it is configured to allow no charging of the storage unit from the electric grid.
The commission noted that it also opened its investigation, which will focus first on distributed generation paired with storage and later consider standalone storage.
Among other things, the commission said that Docket No. 5000 is intended to be a deliberative investigation to ensure that implementation of state energy policy goals are achieved in a least-cost manner consistent with certain goals, principles, and cost-benefit framework.