States have the ability to drive clean energy deployment, not only through statewide goals for adoption, but also through key policies that determine the cost and process of integrating energy resources on the electric grid. One such policy is a state’s¹ set of rules² on interconnection. 

Interconnection policies specify the processes, timelines, costs, and technical requirements associated with connecting distributed energy resources (DERs)—such as solar and energy storage systems—safely and reliably to the grid. They are effectively “the rules of the road” that must be followed by both interconnection applicants and utilities, and play an essential role in enabling a state’s clean energy transition.

Interconnection procedures for the distribution system (which delivers electricity from the high-voltage transmission system to customers at lower voltages) are approved by state public utility commissions and can be found in state rules or tariffs. 

Because interconnection rules dictate how DER projects get reviewed and approved for operation on the electric grid, they are critical to the fair and efficient processing of interconnection requests. If the rules are designed to promote streamlined review and clarity around timelines and costs, they can help to ensure that solar and other distributed energy resources are interconnected more rapidly. If the rules do not incorporate best practices related to costs, timelines, and review process transparency, the result is often clogged interconnection queues and delays that can stretch for months or years, as well as canceled projects if required grid upgrade costs are too high. 

As a starting point for developing their rules, many states have relied on two resources: the Federal Energy Regulatory Commission’s (FERC) Small Generator Interconnection Procedures (SGIP), and the Interstate Renewable Energy Council’s (IREC) Model Interconnection Procedures (IREC 2023 Model). State interconnection procedures may also include references to technical interconnection standards, such as the Institute of Electric and Electronic Engineers’ 1547-2018 standard (IEEE 1547™-2018), IEEE Standard for Interconnection and Interoperability of Distributed Energy Resources with Associated Electric Power System Interfaces.

The purpose of grading states on their interconnection procedures through Freeing the Grid is to provide states with a resource to measure their rules and see how they compare to other states’, as well as to share guidance on best practices for interconnection. The grading is solely based on whether a provision or practice is explicitly included or referenced in the state’s interconnection rules that apply to all jurisdictional utilities (i.e., the grading does not include interconnection provisions included in non-statewide interconnection rules, such as public utility commission orders that have not been formally adopted in the rules or individual utility technical documents). Though this does not capture how the rules have been implemented, it is important for a state to standardize and codify interconnection practices to provide greater transparency into the process for both utilities and interconnection customers, ensure that interconnection applicants have a process that can be referenced if disputes arise, and ultimately provide utility accountability for any process delays.