Duquesne Light Solar Interconnection and Net Metering Policy
Duquesne Light Company (DLC) serves approximately 600,000 customers across Allegheny and Beaver counties in southwestern Pennsylvania, making it the primary electric utility for the Pittsburgh metropolitan area. This page covers the interconnection application process, net metering compensation structure, size thresholds, and governing regulatory framework that apply specifically to DLC-territory solar installations. Understanding these utility-specific rules is essential before designing, sizing, or contracting a solar energy system within DLC's service area.
Definition and scope
Duquesne Light Company operates as a regulated electric distribution company (EDC) under the jurisdiction of the Pennsylvania Public Utility Commission (PUC). The PUC administers net metering and interconnection standards for all Pennsylvania EDCs under 52 Pa. Code §§ 75.1–75.20, which implement the requirements of the Pennsylvania Alternative Energy Portfolio Standard Act (Act 213 of 2004) and subsequent amendments.
Within this framework, DLC's interconnection and net metering policy governs:
- Residential, commercial, and agricultural solar photovoltaic (PV) systems
- Systems that are grid-tied and export excess generation to the distribution grid
- Facilities located within DLC's certificated service territory (Allegheny and Beaver counties)
What this page does not cover: Systems located outside DLC's service territory are governed by different utility-specific policies — PECO, PPL, Met-Ed, and other Pennsylvania EDCs each maintain separate tariffs. Off-grid solar installations that have no grid connection fall outside interconnection and net metering scope entirely. Federal-level policies administered by the Federal Energy Regulatory Commission (FERC) under PURPA apply to larger generators above certain capacity thresholds and are distinct from the state PUC framework described here. For a broader map of Pennsylvania electric utility territories and solar jurisdictions, that resource covers the full EDC landscape.
How it works
Solar interconnection with Duquesne Light proceeds through a structured application and review sequence governed by 52 Pa. Code § 75 and DLC's own filed tariff schedules. The process has five discrete phases:
- Pre-application inquiry — The customer or installer submits a pre-application request identifying system size, location, and proposed point of interconnection. DLC uses this to identify whether expedited review or a full study is required.
- Interconnection application submission — A formal application is filed with DLC, accompanied by single-line diagrams, equipment specifications, and the applicable fee. Systems at or below 10 kilowatts (kW) AC qualify for expedited "Level 1" review under the PUC's simplified interconnection rules.
- Technical review and study — DLC engineers evaluate the proposed system for safety, power quality, and grid impact. Systems above 10 kW AC and up to 2 megawatts (MW) AC proceed through a "Level 2" review, which may include a distribution system impact study.
- Interconnection agreement execution — Once technical review is complete, DLC issues an interconnection agreement. The customer signs and returns it, and any required upgrades to metering or protective equipment are scheduled.
- Permission to operate (PTO) — After the installation passes inspection by the local authority having jurisdiction (AHJ) and the utility conducts a final meter check, DLC issues written permission to operate. Generation cannot export to the grid until PTO is received.
Net metering under DLC's tariff credits excess kilowatt-hours (kWh) exported to the grid against the customer's consumption at the full retail rate. Credits accumulate monthly and roll forward. At the end of each 12-month annualization period, any remaining surplus credit is compensated at the utility's avoided-cost rate rather than the full retail rate, consistent with 52 Pa. Code § 75.13.
The system size cap for net metering eligibility is 110% of the customer's prior 12-month average load, with an absolute ceiling of 3 MW AC for non-residential accounts and 50 kW AC for most residential accounts under current PUC rules. For foundational context on how solar energy systems generate and export power, the conceptual overview of Pennsylvania solar energy systems provides the underlying technical grounding.
Safety standards applicable to DLC interconnections include IEEE 1547-2018 (Standard for Interconnection and Interoperability of Distributed Energy Resources) and UL 1741 (Standard for Inverters, Converters, Controllers and Interconnection System Equipment for Use With Distributed Energy Resources). Inverters must carry UL 1741 listing to be eligible for interconnection approval.
Common scenarios
Residential rooftop system (≤10 kW AC): The most common DLC interconnection scenario. Level 1 expedited review applies, DLC targets a 20-business-day review window, and no distribution study is typically required. A bi-directional meter is installed at no charge to the customer under the PUC's net metering rules.
Small commercial system (10–100 kW AC): Level 2 review applies. A distribution impact study may be triggered, adding 45–90 days to the timeline depending on study complexity. The customer bears the cost of any required distribution upgrades identified in the study.
Large commercial or industrial system (100 kW–2 MW AC): A full interconnection study is standard. These accounts may also interact with Pennsylvania's alternative energy portfolio standard and SREC markets, creating compliance considerations beyond the DLC tariff alone.
Battery storage additions: Adding a solar battery storage system to an existing DLC-interconnected installation requires a supplemental interconnection application. IEEE 1547-2018 compliance requirements extend to the combined AC output of the inverter and storage system.
Decision boundaries
The threshold distinctions within DLC's interconnection framework create meaningfully different cost and timeline profiles:
| System Size (AC) | Review Level | Study Required | Typical Timeline |
|---|---|---|---|
| ≤10 kW | Level 1 (Expedited) | No | 20 business days |
| 10 kW–2 MW | Level 2 (Standard) | Possible | 45–120 days |
| >2 MW | FERC/PUC Large Generator | Yes | Case-by-case |
A system sized at, for example, 10.1 kW AC is subject to Level 2 review even though it exceeds the Level 1 threshold by a minimal margin. This boundary is fixed by regulation, not DLC discretion.
Net metering versus non-net-metered interconnection is a similarly hard boundary: systems that exceed the 110% load-matching cap or the absolute size ceiling are eligible for interconnection but not for net metering credits, instead receiving compensation under a separately negotiated power purchase or avoided-cost arrangement.
The regulatory context for Pennsylvania solar energy systems page addresses the full statutory hierarchy — from federal FERC authority through PUC rulemaking down to individual utility tariffs — that frames where DLC's policy authority begins and ends. Permitting at the municipal and county level (electrical permits, building permits, and AHJ inspections) runs parallel to the DLC interconnection process and is not controlled by DLC; those requirements originate with local governments and the Pennsylvania UCC (Uniform Construction Code). A comprehensive guide to Pennsylvania solar energy systems on the home page of this resource covers the statewide policy environment within which DLC operates.
References
- Pennsylvania Public Utility Commission — Net Metering
- 52 Pa. Code Chapter 75 — Net Metering
- Pennsylvania Alternative Energy Portfolio Standard Act (Act 213 of 2004)
- IEEE 1547-2018 — Standard for Interconnection and Interoperability of Distributed Energy Resources
- UL 1741 — Standard for Inverters, Converters, Controllers and Interconnection System Equipment
- Duquesne Light Company — Official Utility Site
- Federal Energy Regulatory Commission (FERC) — Distributed Generation Interconnection