What Is Permission to Operate (PTO) for Solar?

The panels are on the roof, the crew has packed up, and the system is sitting there doing nothing. That pause surprises a lot of new solar owners. It's normal, and it ends with one approval from your utility: permission to operate.

This article covers what happens in that last stretch, why it matters, and what changes once you're approved. For the whole project from first quote to power-on, see our guide to going solar, step by step.

What is permission to operate for solar?

Permission to operate, or PTO, is your utility's final approval to turn on your solar system and run it connected to the grid. It is the last step of a home solar project. Utilities don't all use the same name: Eversource in Massachusetts, for example, talks about a system being "authorized to operate." The meaning is the same.

Before the utility gives it, two other things have to happen: your town has to inspect and sign off on the work, and the utility has to get the paperwork and set up your meter. Your installer handles that process and tells you when the approval comes through.

It helps to keep the two approvals straight. The town inspection asks whether the system was built safely and to code. Permission to operate asks whether the utility is ready to have it running on its lines and counting toward your bill. You need both, in that order.

What happens at the solar inspection?

Your town's inspector, from the building or electrical department, checks the installed system against the permits that were approved before the work began. They look at how the racking is attached to the roof and whether the wiring, disconnects and labels meet the electrical code.

Your installer schedules the inspection and is usually there for it. You may need to let the inspector in to see your electrical panel. If something needs to change, the inspector lists it, the installer fixes it, and the inspector comes back. Passing the first time is the fastest route, which is one reason the quality of the original work matters.

What happens after the inspection passes?

Once the town signs off, a certificate of completion goes to your utility. It tells the utility the system was built as approved and passed inspection. From there:

1. The utility reviews the paperwork. It checks the certificate against the interconnection application your installer filed before the work began.
2. The utility may inspect too. Rhode Island Energy, for example, says it may do its own inspection or a witness test before operation, though that isn't commonly required for small residential systems. The town and the utility check different parts of the connection, under different rules.
3. You get a new meter. The utility installs a meter that can count the power you send to the grid as well as the power you use.
4. The utility grants permission to operate. Your installer tells you, and you turn the system on.

How long does it take to get permission to operate?

On a typical Evergreen Solar project, activation takes usually about 3 to 5 weeks after installation. That window covers the inspection, the certificate of completion, the new meter and the utility's approval. It sits at the end of a project that usually runs about 10 to 16 weeks from signing, and our pillar guide shows how the whole schedule adds up.

Timing depends on how quickly your town can schedule an inspector and how busy your utility's team is. A correction from the inspector adds a return visit.

You can help the last stretch go smoothly:

• Answer quickly when your installer calls to set the inspection date.
• Keep a clear path to your electrical panel and your outdoor meter, since the utility needs to reach the meter to swap it.
• Keep dogs inside on inspection and meter days.
• Leave the system off, even if the panels look ready, until your installer says it's approved.

Why can't you turn solar panels on before you have permission?

It's tempting to flip the switch on a sunny day. Wait for the approval anyway, for three reasons:

• The system isn't approved to send power onto the grid yet. The utility controls what connects to its lines. Grid-tied systems are designed to shut off during outages so they don't send power onto lines that crews are repairing, and the utility's review checks that your equipment meets its rules.
• You won't get credit for the power. With Eversource in Massachusetts, net metering credits start only after the system is authorized to operate.
• The meter may not be ready. Until the new meter is in, the power you send back may not be counted the way your net metering bill expects.

Your installer will tell you the moment it's official and walk you through turning the system on.

What happens to net metering credits and incentives after PTO?

Permission to operate is the point when the money side of solar starts. Here's what it unlocks in each state we serve:

Massachusetts. Your installer applies to SMART 3.0 for you before installation. With Eversource, net metering credits show on your bill under "Other Charges or Credits." Our guide to SMART 3.0 covers rates and enrollment.

Connecticut. In Eversource territory, the RRES application is reviewed together with the interconnection application, so the incentive and the approval move as one. The option you picked stays with the house. See our guide to Connecticut's RRES program.

Rhode Island. If you own your system and used the Renewable Energy Fund grant, it had to be approved before installation began. Our guide to the Rhode Island solar grant explains how it works.

What should you do in your first weeks with solar?

Once the system is on, a few small steps help you start off right:

• Set up monitoring. The monitoring app shows what your system produces, what your home uses and the system's health. Check it over the first few sunny days to confirm production looks right, and call your installer if it reads zero on a clear day.
• Read your first full bill. The first bill after approval may cover only part of the month with solar. Look for the net metering credit line, and expect the biggest credits in summer and smaller ones in winter. Our guides to how net metering works and your electric bill with solar walk through it.
• Know your coverage. Every Evergreen Solar package includes a 25-year comprehensive solar warranty and a 25-year power production guarantee. With a lease or PPA, the company that owns the system also handles maintenance and repairs.

If you haven't started yet and want to know what solar would look like on your home, call us at (508) 507-2908 or see the incentives on our pages for Massachusetts, Connecticut and Rhode Island.

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