How to Manage Renewable Energy Grid Interconnection to Avoid Project Delays

By connecting a solar installation to the utility grid, you can meet your energy demand needs and earn rebates on excess energy production. However, the local utility company must first assess your project for electrical safety and its overall impact on grid stability. This process is commonly known as grid interconnection.

Every utility has a unique grid interconnection application. In order to keep a project on schedule, it is crucial to understand and effectively manage this process.  What does it take to get the green light from the utility for a grid-connected solar power system, which may include battery energy storage, EV charging and other clean energy systems?

Our Experts Kathi Czahar and Dan Hicks Explain Grid Interconnection

To better understand what’s involved for grid interconnection, we’ve turned to our project interconnection experts Kathi Czahar and Dan Hicks to take the mystery out of the interconnection process and help you understand how it impacts project success. Kathi and Dan work with utilities across the United States every day to help REC Solar – a Duke Energy Renewables company – commercial customers secure approval and keep projects on schedule.

southern california edison nem interconnection

Source: Southern California Edison (SCE)

What’s Involved in Renewable Energy Grid Interconnection?

Just as every electric utility has unique distribution and transmission systems,they also have unique policies and processes that dictate how distributed energy resources (like solar) can connect to the grid. That said, the grid interconnection process is similar across U.S. utilities in two primary ways:  

  1.     The application for interconnection at the outset of a renewables project
  2.     Installation inspection to gain final permission to operate

southern california edison utility online interconnection application review process

Every utility publishes specific (and often complex) interconnection requirements and timelines. However, interpretation of approvals can vary. The interconnection application process can be overwhelming, and often necessitates deep technical expertise. The application will need to provide detailed information about the project site and installation needs, including specifics on the intended system size, capacity limits, equipment and system ratings, energy production estimates and more. An electrical one- or three-line diagram that illustrates the project and grid interconnection also needs to be submitted alongside all the other project data. All this information needs to be supplied to the local utility exactly as specified in their published requirements.

sample interconnection line drawing

Sample of three line diagram or drawing required for interconnection with Hawaiin Electric Company (HECO).

The utility will not only look at your proposed system during the application process, but also its own infrastructure to ensure that your project can be adequately supported by the local grid. Any grid upgrades that need to occur, such as service transformer replacements and bi-directional switches, will be planned early on and built into the utility’s schedule.

The utility will also calculate an interconnection fee dependent on overall system size, anticipated generation and required utility upgrades.

Once application is conditionally approved and the interconnect fee is paid, grid upgrades are complete, and the PV project is complete with all approvals, the final step of the process is an on-site system inspection. This part of the process often involves scheduling an on-site visit by a utility representative who confirms that equipment ratings, point of interconnection and overall system design comply with information provided at the outset of the project. 

How Long Does the Solar Interconnection Process Typically Take?

The amount of time it takes to close out a project and receive utility Permission to Operate (PTO) will vary by utility, region, project size, grid updates required – and ultimately, by — the effectiveness of your vendors and project management teams. Some utilities publish a timeline for interconnection. However, it is important to have knowledgeable experts to prepare your interconnection applications. If an application is incomplete, it can cause significant delays in completing the process.

The best time to apply for utility
interconnection is in the spring and fall.

From start to finish, this process can take anywhere from three to 18 months depending on required system upgrades. In all cases, online processing is much faster than manual processing.

If the utility needs to make upgrades to its own grid infrastructure, this work can extend project schedules further.

What Does it Take to Simplify Grid Interconnection?

The key to navigating solar interconnection is to work with experts who help:

  1. Start the process early (sometimes even before contracts are complete!)
  2. Set realistic expectations based on experience with utility-driven timelines.
  3. Leverage established relationships and familiarity with your utility/utilities.
  4. Maintain clear, proactive and transparent communications among your project management teams, utility and project owner to keep everyone informed along the way.

Starting the process early is crucial, especially in states like California and Hawaii where solar growth has increased exponentially. The increasing popularity of renewables and the demand for decarbonized electricity and transportation require more resources to keep up with interconnection requests. Furthermore, if you anticipate your solar or other clean energy project will be large enough to require utility upgrades, you should start the interconnection request far in advance of breaking ground to give your electric utility time to make any necessary upgrades to the grid.

The timing of your application can also impact project delays. The best time to apply for utility interconnection is in the spring and fall; weather delays in the winter or during storm season can set back project schedules.

process for pv permitting and application review

Although the grid interconnection process may seem daunting, making an investment in renewable, resilient energy should be an exciting process – not a headache. By working with a commercial energy integration solutions team that offers in-house services for everything from project finance and management to expert design, construction, operations, maintenance, monitoring and analysis, you can better manage your organization’s expectations while lowering the cost and complexity of critical stages like grid interconnection and beyond.

About REC Solar

Kathi and Dan bring over a decade of combined solar interconnection and renewable energy experience to REC Solar, a Duke Energy Renewables company. For more than 20 years, REC Solar has helped its commercial clients finance, build, integrate, operate and maintain renewable energy solutions. Today, we are one of the nation’s leading onsite commercial energy solution providers building solar generation, energy storage, microgrids and EV charging for nearly 800 installations across the US. To learn more, go to or find us @recsolar on Facebook, LinkedIn and Twitter.

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