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Get a Free QuoteHow long does your utility take to approve solar? Interconnection timelines for 22 utilities across 9 states, with process steps, common bottlenecks, and tips to avoid delays.
Quick Answer
Solar interconnection takes 12-40 business days depending on your utility. The fastest are NH Electric Co-op and Burlington Electric at 18 days average. The slowest are PSE&G and National Grid (MA) at 30 days average. The process involves application review, engineering study, inspection, meter swap, and PTO issuance. Transformer capacity studies (triggered when multiple homes on the same line have solar) can add 2-12 weeks.
18
Fastest (Avg Days)
NH Electric Co-op
30
Slowest (Avg Days)
PSE&G
22
Utilities Tracked
9 states
5
Process Steps (avg)
Application to PTO
Average business days from interconnection application submission to Permission to Operate (PTO). Sorted by fastest average. Range reflects typical best-case to worst-case for standard residential systems under 25 kW.
| Utility | State | Avg Days | Range | Portal | Main Bottleneck |
|---|---|---|---|---|---|
| NH Electric Co-op | NH | 18 | 12-22 days | Seasonal demand spikes (spring) | |
| Burlington Electric (BED) | VT | 18 | 12-22 days | Dense downtown infrastructure | |
| Austin Energy | TX | 18 | 12-22 days | Online | None — municipal utility with streamlined process |
| Eversource (NH) | NH | 20 | 15-25 days | Online | Rural line capacity in northern territories |
| Liberty Utilities | NH | 20 | 15-25 days | Small interconnection team | |
| Central Maine Power | ME | 20 | 15-25 days | Online | NEB (net energy billing) application processing |
| Oncor | TX | 20 | 15-28 days | Online | DFW metro volume spikes in spring |
| CPS Energy | TX | 20 | 15-25 days | Online | SolarHost program enrollment backlog |
| Unitil (MA/NH) | MA | 22 | 15-28 days | Small team — vacation periods create delays | |
| Versant Power | ME | 22 | 15-28 days | Rural infrastructure — single-phase line constraints | |
| Green Mountain Power | VT | 22 | 15-28 days | Online | Act 250 crossover for larger systems |
| PPL Electric | PA | 22 | 15-28 days | Online | Rural line capacity studies |
| Duquesne Light | PA | 22 | 15-28 days | Online | Small service territory — limited staff |
| Eversource (CT) | CT | 25 | 18-32 days | Online | Inspection scheduling in Fairfield County |
| United Illuminating | CT | 25 | 18-30 days | Online | Infrastructure age in Bridgeport/New Haven territories |
| Atlantic City Electric | NJ | 25 | 18-32 days | Online | Shore zone inspection scheduling |
| PECO Energy | PA | 25 | 18-32 days | Online | Philadelphia metro volume |
| CenterPoint Energy | TX | 25 | 18-35 days | Online | Houston metro infrastructure age |
| Eversource (MA) | MA | 28 | 20-35 days | Online | Net metering application review backlog |
| JCP&L | NJ | 28 | 20-35 days | Online | Meter swap scheduling delays |
| National Grid (MA) | MA | 30 | 22-40 days | Online | Meter exchange scheduling backlog |
| PSE&G | NJ | 30 | 22-40 days | Online | High volume — largest NJ utility, massive backlog |
Business days (Mon-Fri). Data from NuWatt project records and utility reporting, Q4 2025 through Q1 2026. Systems >25 kW or requiring line upgrades may take significantly longer.
Every utility follows a similar process, though the number of steps and time per step varies. Here is what happens after your solar panels are installed and your municipal electrical inspection passes.
Installer submits interconnection application with system design, single-line diagram, and equipment spec sheets to the utility.
Utility engineers review system design for code compliance, conductor sizing, and grid impact. May trigger a capacity study if the transformer is near saturation.
Utility issues conditional approval and orders a bi-directional net meter (if not already installed). Meter availability can cause delays.
Municipal electrical inspection must pass first. Then utility may perform its own inspection or accept the municipal inspection certificate.
Utility installs the net meter and activates the interconnection agreement. You receive Permission to Operate (PTO) and can begin exporting to the grid.
Serves ~12% of NH (rural areas, Lakes Region). Cooperative model — member-owned. Fewer bureaucratic layers means faster approval. Limited online tools.
Bottleneck: Seasonal demand spikes (spring)
Municipal utility — 100% renewable. Smallest in our dataset but fastest. In-house review process with no external queue. Burlington-only.
Bottleneck: Dense downtown infrastructure
Municipal utility. In-house generation, transmission, and distribution. Fastest interconnection in TX. Value of Solar tariff replaces traditional net metering.
Bottleneck: None — municipal utility with streamlined process
Covers ~70% of NH. NEM 2.0 applications are straightforward. Fastest Eversource division for interconnection.
Bottleneck: Rural line capacity in northern territories
Covers ~6% of NH (Salem, Derry, Londonderry area). Small but responsive team. Email-based process is less convenient but faster for simple residential systems.
Bottleneck: Small interconnection team
Covers ~75% of ME. Avangrid-owned (same parent as UI in CT). NEB applications are straightforward for rooftop solar. Community solar projects face longer queues.
Bottleneck: NEB (net energy billing) application processing
Largest TX delivery utility (DFW, Waco, Tyler). Deregulated — Oncor handles delivery/interconnection only, not billing. Online portal is efficient but high volume in spring.
Bottleneck: DFW metro volume spikes in spring
San Antonio municipal utility. Fast interconnection but SolarHost incentive program has its own review timeline. System inspection is combined with interconnection.
Bottleneck: SolarHost program enrollment backlog
Small utility (~105K customers). Personalized service but limited staff. Holiday seasons can add 1-2 weeks. Covers Fitchburg MA and Concord/Hampton NH.
Bottleneck: Small team — vacation periods create delays
Covers northern and eastern ME (~25% of state). Lower solar penetration means fewer upgrade issues. Email-based process but responsive staff.
Bottleneck: Rural infrastructure — single-phase line constraints
Covers ~75% of VT. Very solar-friendly utility with Powerwall leasing program. Systems under 15 kW are fast-tracked. Larger systems may trigger Act 250 review.
Bottleneck: Act 250 crossover for larger systems
Covers central and eastern PA (Lehigh Valley, Lancaster, Harrisburg). Rural areas occasionally need line capacity studies. Urban areas are fast.
Bottleneck: Rural line capacity studies
Covers Pittsburgh metro only (~600K customers). Smaller team but lower volume than PECO. Generally efficient process.
Bottleneck: Small service territory — limited staff
Separate from Eversource MA/NH — different interconnection team and portal. CT Green Bank involvement does not slow interconnection.
Bottleneck: Inspection scheduling in Fairfield County
Covers Greater New Haven and Bridgeport areas. Aging grid infrastructure means more frequent transformer studies. Avangrid-owned.
Bottleneck: Infrastructure age in Bridgeport/New Haven territories
Exelon subsidiary. Covers southern NJ. Shore communities (Atlantic City, Cape May) have flood zone requirements that add inspection steps.
Bottleneck: Shore zone inspection scheduling
Exelon subsidiary. Covers southeast PA including Philadelphia metro. Online portal is modern and well-maintained. SREC registration is separate from interconnection.
Bottleneck: Philadelphia metro volume
Covers Houston metro. Older grid infrastructure means more frequent studies. Hurricane hardening requirements can add review steps for coastal-adjacent areas.
Bottleneck: Houston metro infrastructure age
Largest MA utility. SMART program enrollment does not delay interconnection. High-solar neighborhoods may trigger transformer study (adds 2-4 weeks).
Bottleneck: Net metering application review backlog
FirstEnergy subsidiary. Covers central/northern NJ. Infrastructure is older than PSE&G territory — more frequent transformer studies.
Bottleneck: Meter swap scheduling delays
Covers central and southeast MA. Meter swap can take 1-2 weeks after inspection passes. Net metering cap tracking sometimes causes delays.
Bottleneck: Meter exchange scheduling backlog
Covers north/central NJ. Highest solar penetration of any NJ utility creates persistent backlog. ADI (SuSI) enrollment does not delay interconnection but adds a parallel process.
Bottleneck: High volume — largest NJ utility, massive backlog
Solar panels are on your roof and the inverter is connected, but the system is not producing power. Most modern inverters have anti-islanding protection that prevents operation without utility authorization.
The utility replaces your old meter with a bi-directional net meter that can measure both power consumption and export. In some territories, a smart meter is already installed and just needs reprogramming.
Permission to Operate is issued via email or mail. Your installer activates the inverter, and your system begins producing power. Net metering credits start accruing from this date forward.
Experienced installers know the interconnection team, understand the application requirements, and submit complete applications the first time. Rejected applications restart the queue.
Ask your installer to check if your neighborhood transformer has capacity. If 3+ homes on your circuit already have solar, a capacity study is likely — this adds 2-12 weeks.
Spring and summer are peak solar installation seasons. Utility interconnection queues are shortest in October-February. A winter install often means faster PTO.
Utilities will not begin interconnection review until the municipal electrical inspection passes. A failed inspection adds 1-2 weeks for re-inspection scheduling.
If your electrical panel needs upgrading (100A to 200A), schedule it before installation day. Panel upgrades that happen after installation delay the inspection and interconnection.
Log into the utility portal (or have your installer check) weekly. Applications occasionally get stuck in review queues and a status inquiry can unstick them.
Eversource interconnection takes 20-35 business days in Massachusetts, 18-32 days in Connecticut, and 15-25 days in New Hampshire. The MA territory is slowest due to higher solar penetration and net metering backlog. The NH territory is fastest. All three use online portals.
Interconnection requires utility engineering review, meter procurement, and coordination with the municipal inspection. Unlike building permits (which are controlled by the municipality), interconnection depends on the utility's internal queue, staffing, and meter inventory. The homeowner and installer have limited ability to expedite it.
No. Operating solar panels without Permission to Operate (PTO) violates your interconnection agreement and may violate state electrical codes. Exporting power to the grid without utility knowledge creates safety hazards for line workers. Most modern inverters will not produce power without utility authorization (anti-islanding protection).
When multiple homes on the same distribution transformer install solar, the combined export can exceed the transformer's capacity. The utility performs a capacity study (2-4 weeks) and may require a transformer upgrade (4-12 weeks). This is more common in neighborhoods with high solar adoption and is the single biggest potential delay.
Most large utilities (Eversource, National Grid, PSE&G, PECO, Oncor) have online portals where you can track application status. For smaller utilities (Unitil, Liberty, NHEC, BED) that use email-based processes, your installer should be checking status weekly and can usually get a direct update from the interconnection team.
For residential systems under 25 kW, interconnection fees are $0 in most states — utilities are required to provide standard interconnection at no cost. The main exception is if a transformer or line upgrade is required. In that case, the utility may charge the homeowner for the upgrade ($2,000-$15,000) or split the cost among all customers on that circuit.
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