In February 2011, the DPU opened up a docket to examine net metering and interconnection of distributed generation. While the intent is to make changes to net metering, issues relating to interconnection will be addressed. For more information about that docket, please visit the DPU Docket system, Docket 11-11. In addition, DPU Docket 11-75 is an ongoing investigation on distributed generational interconnection.
Massachusetts's interconnection standards apply to all forms of distributed generation (DG), including renewables, and to all customers of the state's four investor-owned utilities (Unitil, NSTAR, National Grid, and Western Massachusetts Electric Company).
The Model Interconnection Tariff (most recently amended in March 2013) includes provisions for three basic paths for interconnection.
- The Simplified interconnection process applies to IEEE 1547.1-certified, inverter-based facilities with either 1) a power rating of 15 kW for single-phase systems located on radial EPSs under certain conditions; 2) a power rating of 25 kW or less for three-phase systems (depending on system configuration), located on radial EPSs under certain conditions; 3) a power rating of less than 1/15 of the customer's minimum load and located on a spot network EPS; or 4) a power rating of less than 1/15 of the customer's minimum load and 15 kW or less and located on an areas network EPS with a rating of less than 1/15 of the customer's minimum load and 15 kW or less. There are no fees associated with the simplified process.*
- The Expedited interconnection process is for IEEE 1547.1-certified facilities that pass certain pre-specified screens on a radial EPS. Application fees are based on the size of the system.*
- The Standard process is for all other facilities that do not meet the specifications of the Simplified or Expedited process for systems on radial and spot network EPSs, and for all facilities on area network EPSs. Application fees are based on the size of the system.*
The issue of interconnection to network systems is particularly important in Massachusetts because network systems are commonly used in dense urban areas, such as Boston. Order 11-75-E implemented a more transparent Supplemental Review screen process for projects that fail the initial Simplified and Expedited Screens. If a project fails the Simplified and Expedited screens, it must pass three supplemental review screens, otherwise it must go through the full standard review process. Massachusetts uses a 100% of minimum load penetration screen in the supplemental review process. If the generating capacity is less than 100% of minimum load, it may not require a detailed study. In addition to these different paths, all systems 500 kW or greater, facility owners must request and receive a pre-application report from the utility. The pre-application report is optional for facilities less than 500 kW; no fee is charged for this report.
For the simplified and expedited interconnection paths, technical requirements are based on the IEEE 1547 and UL 1741 standards. A manual external disconnect switch may be required at the discretion of the utility (project-specific, not required in the tariffs). Utilities must collect and track information on the interconnection process. This information will be used in revising and updating the standards.
In August 2011, the Department of Energy Resources (DOER) submitted the Massachusetts Distributed Generation Interconnection Report to the DPU outlining its recommendations for improved interconnection policies and processes based on its research, which included an extensive stakeholder survey, conducted in April 2011. In September 2012, the Massachusetts Distributed Generation Interconnection Working Group submitted its final report recommending changes to the state's interconnection standards. DPU incorporated changes from comments submitted in Docket 11-75, and adopted the report those changes in March 2013.
*As part of Order 11-75-E (March 2013), the Department of Public Utilities called for an investigation of fees associated with interconnection. The application fees may change as a result of this investigation.