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Municipal utilitySeattle City Light interconnection application
Seattle City Light is a municipal utility serving 472,309 residential customers in Washington (EIA-861, 2025). Applications: Own online portal (City Light online Electric Service Application). Gridpol files Seattle City Light interconnection applications for licensed installers – solar, storage and EV chargers – with single-line diagram and site plan, unlimited for $500 a month.
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Process verified from Seattle City Light’s official sources (see below). Fee amounts and review timelines not published on the page; check DER Interconnection Handbook on first project.
Seattle City Light at a glance
City of Seattle
TypeMunicipal utility
EIA utility ID16868
Residential customers472,309 (EIA-861, 2025)
Net-metered residential customers8,695 (EIA-861, 2025)
Service territory1 county in Washington
How to applyOwn online portal – City Light online Electric Service Application · official link
Who submitsSolar installer or customer submits the Electric Service Application; customer signs the Interconnection Agreement (Adobe Sign) and the Commissioning and Testing Attestation; PTO letter goes to the Primary Contact on the application.
Export compensationNEM – Net metering (Washington RCW 80.60)
No export credit before PTO date. Not available in network areas.
Documents Seattle City Light asks for
- Interconnection application formOnline Electric Service Application (separate application for extra service work) Gridpol prepares this.
- Single-line diagram (one-line)One-line and riser diagrams Gridpol prepares this.
- PV module spec sheetManufacturer data sheet of the modules.
- Inverter spec sheetUL/IEEE compliant
- Site plan / site layoutDrawn by us from your roof sketch or photos: array, inverter, battery, disconnect, meter and main panel locations. Gridpol prepares this.
- Interconnection agreementLevel 1-2 or Level 3-4 Interconnection Agreement; may be submitted unsigned with application, signed by customer via Adobe Sign after approval
- Final inspection sign-offProof of passed AHJ final inspection emailed to SCL_SolarRequest@seattle.gov
- Other utility-specific documentCommissioning and Testing Attestation form (provided by ESR/ESE); customer-owned production meter optional with phenolic label, outside meter working area
How the Seattle City Light process runs
- Review DER Interconnection Handbook
- Submit online application with one-line/riser diagrams, specs, site plan (optionally unsigned IA)
- Engineering review if >12 kW AC, battery backup, network area or upgrades
- Sign Interconnection Agreement via Adobe Sign
- Permission to Construct (PTC) letter; do not install before
- Receive and sign Commissioning and Testing Attestation form
- AHJ permit and final inspection; email proof + attestation
- City Light utility inspection
- Pay billed fees
- Permission to Operate (PTO) letter
Fees
| Fee | Applies to | Note |
|---|---|---|
| Applicable fees billed | Party responsible for construction charges | No fixed amount published; customer pays any upgrades required solely for the solar installation |
Utility fees are paid by the installer or customer; they are not part of the Gridpol plan.
Size levels and limits
| Level | Up to | Note |
|---|---|---|
| No engineering review | 12 kW | AC, outside network areas, no battery backup |
| Level 1-2 / Level 3-4 agreements | Per DER Interconnection Handbook | |
| Net metering cap | 100 kW |
Net metering not available (no export) in network areas: most of Downtown, parts of First Hill, South Lake Union, University District. Advanced-meter opt-out customers cannot interconnect.
Storage, EV and stamps
Battery storage
Systems with battery backup may require engineering review. DER Interconnection Handbook covers solar, battery storage and other systems.
Common issues the utility lists
- Interconnection meter socket location not meeting RESC access/placement (1554.33)
- Advanced meter opt-out
- Export proposed in network area
Gridpol’s pre-submission check covers these before we file.
Sources
- Seattle City Light - Installing a Solar Array: https://www.seattle.gov/city-light/construction-services/apply-for-new-or-upgraded-service/solar-installation (retrieved 2026-11-13)
Other utilities in Washington
- Puget Sound Energy (PSE)1,104,338
- Snohomish County PUD349,905
- Avista Utilities247,159
- Clark Public Utilities223,119
- Tacoma Power (Tacoma Public Utilities)177,554
- Rocky Mountain Power (UT, ID, WY) / Pacific Power (OR, WA, CA)114,998
- PUD No 1 of Benton County50,835
- PUD No 1 of Cowlitz County48,849
- PUD No 2 of Grant County43,160
- PUD No 1 of Chelan County42,571
$500 / month
Unlimited interconnection applications. 12-month agreement, signed online. The agreement starts the day you sign; first invoice right away, then monthly.
- Unlimited interconnection applications
- Single-line diagram and site plan for every application
- Pre-submission check against the utility’s requirements
- Homeowner e-signature link for the authorization
- Filing in your utility portal accounts or by the utility’s method
- Utility questions, corrections and resubmissions
- Follow-up through approval, inspection and PTO
- Customer list, exports, API and webhooks
Applications are typically submitted within 2 business days after complete documents. Utility review times are set by each utility.