April 3, 2019

An Overview of Distributed Energy Resource (DER) Interconnection: Current Practices and Emerging Solutions

This report from the Distributed Generation Interconnection Collaborative (DGIC) was commissioned based on the need—identified through DGIC—for a central document summarizing considerations, practices, and emerging solutions across a broad set of topics related to DER interconnection.

The report is targeted at a high-level, strategic-planning audience at utilities who are seeking an overview of DER interconnection issues and approaches and looking to understand how these may relate to their own situations. The audience includes a broad set of utilities and situations, including investor-owned utilities (IOUs), municipal utilities (munis), and cooperatives (co-ops) with a range of current DER penetration levels.

Although some areas of interconnection have established standards, many are still nascent with no clear or accepted best practice. Additionally, the practice most suitable for a given situation will vary depending on the level of DER penetration; the utility, customer, and developer characteristics and preferences; the attributes of the electrical power system; and other factors. This report does not seek to recommend or dictate practices in any of these areas, but rather provides an overview of the status of different aspects of interconnection, existing standards, and emerging solutions currently being explored that can inform utility planning and decisions. Some of this information may also be useful to regulators, policymakers, and DER developers seeking to understand barriers to interconnection, potential solutions currently being explored, and ways to work with utilities on interconnection policies.