The Distributed Energy Resource Interconnection Roadmap identifies solutions to interconnection challenges on the distribution and sub-transmission grids. The roadmap was produced by the U.S. Department of Energy (DOE) Interconnection Innovation e-Xchange (i2X), led by the Integrated Energy Systems Office (IESO). It provides stakeholders with strategies to improve interconnection processes to meet growing demand for more generators, storage systems, large loads, and hybrid facilities on distribution networks.
The U.S. electricity system is changing rapidly as homes and commercial buildings electrify, manufacturing hubs expand, and energy-intensive sectors, such as artificial intelligence (AI) and data centers, continue to grow. Distributed energy projects play an important role in this change because they offer faster integration, closer proximity to loads, and flexibility in balancing loads. However, interconnection processes must accommodate a growing volume of interconnection requests and adapt to local markets with specific needs.
The roadmap is organized around four goals, each critical to the overall mission of i2X : to enable a simple, fast, and affordable interconnection while enhancing the reliability and security of our electric grid. Developed through extensive stakeholder engagement, the roadmap outlines specific actions that each stakeholder group can take to improve interconnection. The solutions are categorized by time scale and deployment level to help stakeholders identify those that best meet regional needs.
This roadmap serves as a companion to the DOE Transmission Interconnection Roadmap, published in April 2024, which identifies solutions to address current challenges in transmission system interconnection.
DER Interconnection Roadmap Goals
Interconnection studies benefit from transparent and accessible data sharing and automation. Utilities providing access to grid data must balance these benefits against workforce strains, computing requirements, and data security. Regulators have a key role in providing guidance to utilities managing data related to grid access and interconnection queues.
Solutions
- Establish guidelines for collecting and sharing grid data that consider trade-offs between value created, effort required, and data security
- Expand and standardize reporting of interconnection data, including project attributes and cost estimates
- Standardize and clarify the technical data that developers of large DER systems must provide on interconnection applications to facilitate interconnection studies
- Establish and maintain frequently updated hosting capacity analysis tools that model the impact of multiple types of DER technologies on the grid
- Broaden the use cases for hosting capacity analysis
This goal aims to streamline the process by which new energy systems connect to the electric grid. The current system struggles with a growing number of interconnection requests, leading to delays. Solutions include better managing these request queues, establishing fair and reasonable procedures, and investing in the skilled personnel needed to handle the workload.
Queue Management
Several solutions may help reduce interconnection queue volumes and delays in the near term while enabling utilities to handle larger queue volumes in the future.
Solutions
- Provide pre-application educational materials and self-service options for small energy projects
- Establish and require interconnection applicants of large energy projects to meet clear criteria about commercial readiness and queue dwell-time
- Implement and enforce appropriate interconnection study timelines and consider penalties for delays in completing studies
- Improve automation of the interconnection application process
- Employ automation in interconnection studies whenever possible
- Enable DERs to increase grid planning flexibility and interconnection speed by avoiding or deferring grid upgrades
- Use a group study process to address existing queue backlogs or avoid future backlogs
- Develop and standardize an interconnection process for energy projects connected to new building construction projects
Just and Reasonable Processes
Customers, such as small businesses and Tribal communities, may have insufficient resources to navigate complicated interconnection processes. The roadmap aims to mitigate these burdens and resolve current issues related to fairness and affordability within the interconnection process.
Solutions
- Promote fairness in interconnection through distribution system planning
- Help under-resourced customers navigate the interconnection process through independent dispute resolution, engineering, administrative, and legal services
Human Capital Investment
Interconnection requires technical expertise from many professionals in the energy sector. Providing them with more training opportunities and better compensation will increase retention and boost productivity. Outreach and recruitment efforts can also raise awareness of these careers and ensure that interconnection-related skills and knowledge are included in educational curricula.
Solutions
- Assess the growth of the interconnection workforce needed to handle increasing interconnection requests
- Upskill the interconnection workforce through continuing education
- Enhance retention and recruitment for interconnection-related jobs
- Grow the interconnection workforce via outreach, curriculum development, and partnerships in postsecondary education
This goal advances fair interconnection outcomes that meet market and policy objectives at lower cost to ratepayers. Solutions include better cost allocation, coordination between interconnection and grid planning, and interconnection studies.
Cost Allocation
Interconnection costs can be allocated to improve economic efficiency and fairness. With respect to interconnecting energy projects, it is important to think beyond the traditional “cost-causer-pays” model.
Solutions
- Reform the existing “cost-causer-pays” model, such that the cost of interconnection-triggered upgrades is distributed fairly among those that benefit from the upgraded feeder circuit
- Build a reserve fund by collecting fees from all interconnecting customers and spend the fund on upgrades triggered by subsequent interconnections
- Use a group study process that reduces per-project interconnection upgrade costs by allocating costs among multiple projects based on their contribution to the triggered upgrade
- Proactively upgrade feeder circuits to accommodate forecasted growth and recover costs from future energy project developers who share the upgraded feeder circuits
Coordination Between Interconnection and Grid Planning
Some cost inefficiencies arise because system-level upgrades are triggered through the interconnection process, meaning they often occur in a piecemeal fashion. This piecemeal approach can impose costs on interconnection customers or ratepayers depending on how regulators balance risks.
Solutions
- Coordinate interconnection for energy projects across the distribution, sub-transmission, and transmission systems
- Improve coordination and data sharing between the distributed energy interconnection process and the system planning process to promote synergy between the two
Interconnection Studies
Interconnection study methods should promote safe and reliable DER interconnection while reducing the need for costly and time-intensive system upgrades.
Solutions
- Distinguish between a generator’s nameplate capacity and export capacity in interconnection studies to accurately reflect project impacts
- Account for potential grid benefits and costs due to energy projects in interconnection studies
- Allow flexible interconnection to mitigate system upgrade costs assigned by interconnection studies
This goal encourages the adoption of existing standards and development of new standards for emerging technologies, including cybersecurity, that protect the integrity of the electric grid.
Interconnection Models and Tools
Improvements to interconnection models and tools can facilitate energy projects while maintaining grid reliability.
Solutions
- Develop and implement new energy system-ready protection schemes
- Develop alternatives to address unintentional islanding and provide research-based methods to evaluate their cost-effectiveness
- Optimize development and use of electromagnetic transient (EMT) models for evaluating the dynamic performance of energy projects
- Improve models for analyzing the seam between the transmission and distribution/sub-transmission systems
- Collect data from energy projects to validate models that ensure aggregate compliance with bulk power system (BPS) reliability standards and perform large-scale reliability assessments
Interconnection Standards
To ensure reliable operation of newly interconnected energy projects, comprehensive interconnection standards are necessary.
Solutions
- Accelerate adoption of the Institute of Electrical and Electronics Engineers (IEEE) 1547 interconnection standard via collaboration among regulators, utilities, and researchers
- Develop standards to mitigate the potential impact of inadvertent export
- Use guidance from IEEE Std 1547.3 to address cybersecurity concerns during the interconnection process
- Develop a cybersecurity risk management plan for interconnecting projects
- Develop and adopt standards that address performance from emerging technologies such as grid-forming inverters and vehicle-to-grid systems
- Develop evidence-based interconnection best practices that promote safety and reliability while allowing for local or regional differences
Measurable Targets for Interconnection Reform
This roadmap includes five target metrics for 2030 that can be measured using publicly available data:
- Decreasing median time from distributed energy project interconnection request to interconnection agreement to:
- Less than one day for small systems (< 50 kilowatts (kW))
- Less than 75 days for medium systems (50 kW – 5 megawatts (MW))
- Less than 140 days for large systems (> 5 MW)
- Increasing completion rate from entering the interconnection queue to executing the interconnection agreement to:
- > 99% for small systems (< 50 kW)
- > 90% for medium systems (50 kW – 5 MW)
- > 85% for large systems (> 5 MW)
- Ensuring all 50 U.S. States, Washington, D.C., and all U.S. territories have public, detailed, and current interconnection queue data
- Ensuring zero disturbance events on the bulk power system exacerbated by inaccurate distributed energy project modeling
- Decreasing the time to restore service after a power outage by 25% (measured by the Customer Average Interruption Duration Index (CAIDI))