Solar Utility Interconnection Design and Application Support

Utility interconnection is where solar projects most often stall. Every US utility has its own single-line diagram format, its own application forms, its own technical review requirements, and its own timelines. Getting interconnection right requires familiarity with each utility's specific conventions and technical staff. RIH Engineering delivers solar interconnection design and application support as an outsourced interconnection engineering partner for US solar EPCs, installers, and developers operating across multiple utility service territories.

What you get

• Single-line diagrams (SLDs) formatted per specific utility conventions (PG&E, ConEd, PSE&G, LADWP, SDG&E, APS, SRP, Xcel, Eversource, National Grid, ComEd, Duke, FPL, Georgia Power, and every other major US utility)
• Three-line diagrams where required by the utility
• Interconnection application preparation and completion
• PG&E interconnection application support, ConEd application support, and equivalent for every major utility
• System impact study support for larger commercial and utility-scale projects
• Feasibility study support where required
• Metering configuration design (net metering, virtual net metering, aggregate net metering)
• Interconnection queue position tracking and utility correspondence
• Response drafting for utility technical review comments

What we handle for you

Utility interconnection is fundamentally paperwork-heavy specialty work. Every utility has different forms, different SLD conventions, different timelines, and different review processes. A solar company operating across 5 to 10 utility territories needs to maintain expertise in 5 to 10 different interconnection workflows. Doing this in-house means dedicating specialist time to something that's pure overhead outside your customer-facing work.

We take interconnection design and application preparation off your plate. You send us the project details and utility. We come back with utility-formatted SLDs, completed interconnection applications, and any required supporting documentation, ready for submission to the utility portal.

The cost of doing this in-house

Interconnection delays are one of the top three causes of solar project schedule slippage in the US. Applications rejected for wrong SLD format, incomplete documentation, or missing supporting studies push project timelines out by weeks or months. Utility interconnection queues in some territories (California, New Jersey, New York) already stretch 6 to 18 months for larger commercial projects. Every application rejection resets your position.

Companies that submit clean, utility-formatted interconnection applications on first attempt clear the process meaningfully faster. Companies with high rejection rates fall further behind, both on individual projects and on utility staff relationships that matter across every project.

Why RIH Engineering is safe to try

Send us one project needing interconnection support. We deliver utility-formatted SLDs and completed application in 3 to 7 days. You submit to the utility. If it comes back with technical review comments, we handle response drafting at no additional cost until interconnection acceptance.

Our team maintains utility-specific templates and current knowledge of application requirements for every major US utility. We update templates as utilities revise their standards and stay current on interconnection policy changes at the state PUC level.

Our process

1. You send us project details, equipment selection, and utility
2. Our engineer verifies utility-specific SLD format and current application requirements
3. SLD drafted per utility conventions
4. Three-line diagram prepared where required
5. Interconnection application completed with all required project data
6. Supporting documentation compiled (equipment specifications, PVRSS listings, metering configuration)
7. System impact study or feasibility study support prepared for larger projects where required
8. Complete interconnection package delivered, typically within 3 to 7 days
9. Ongoing support during utility technical review including response drafting for review comments

Tools and standards

Our interconnection design team works in AutoCAD, utility-specific SLD templates, and utility portals for every major US investor-owned utility, municipal utility, and rural electric cooperative. We maintain current templates for PG&E, ConEd, PSE&G, LADWP, SDG&E, APS, SRP, Xcel, Eversource, National Grid, ComEd, Duke Energy, FPL, Georgia Power, and hundreds of others.

Client-preferred tools: Our team can be trained to use the tool preferred by the client. If your workflow depends on a specific platform, template, or drafting standard, we adapt to it rather than force you into ours.