Interconnection Standards

June 25, 2019


Note: HB 589, signed in July 2017, requires the NCUC to adopt an expedited review process for swine and poultry waste energy projects of 2 MW or less. The NCUC issued an order in June 2019 with revisions to the interconnection standard including provisions for adding energy storage at existing solar PV sites, and expedited study of interconnection standard for small swine and poultry waste facilities. 

The North Carolina Utilities Commission (NCUC) first adopted comprehensive interconnection standards for distributed generation in 2005. The NCUC later updated the interconnection standards in 2008 and 2015. The current NCUC standards, which are similar to the Federal Energy Regulatory Commission’s (FERC) interconnection standards for small generators, govern interconnection to the distribution systems of the state's three investor-owned utilities: Duke Energy Progress, Duke Energy Carolinas, and Dominion North Carolina Power.* The standards apply to all state-jurisdictional interconnections (including interconnection of three-phase generators) regardless of the capacity of the generator, the voltage level of the interconnection, or whether the customer intends to offset electricity consumption or sell electricity.

Size Criteria
The NCUC standards, like the FERC standards, use a three-tiered approach to simplify the interconnection process:

  • Inverter Process: Systems up to 20 kilowatts (kW) 
  • Fast Track Process: Systems larger than 20 kW that meet the eligibility criteria in the table below 
  • Study Process: Systems that fail to qualify for the Fast Track Process

Line Voltage Fast Track Eligible Regardless of Location Fast Track Eligibility on a Mainline and less than 2.5 Electrical Circuit Miles from Substation
Less than 5 kV Less than or equal to 100 kW Less than or equal to 500 kW 
Between 5 kV and 15 kV Less than or equal to 1 MW  Less than or equal to 2 MW 
Between 15 kV and 35 kV Less than or equal to 2 MW  Less than or equal to 2 MW 
Greater than or equal to 35 kV Not eligible Not eligible

Utilities may not require residential customers to carry liability insurance beyond the amount required by a standard homeowner’s policy ($100,000 minimum). Non-residential generators proposing to interconnect a system no larger than 250 kW are required to carry comprehensive general liability insurance in the amount of at least $300,000. Non-residential generators proposing to interconnect a system that is larger than 250 kW are required to carry comprehensive general liability insurance in the amount of at least $1,000,000. Customers that meet certain eligibility requirements are allowed to self-insure. 

External Disconnect Switch
Utilities are authorized to require an external disconnect switch, but must reimburse owners of systems smaller than 10kW for the cost of the switch. Interconnection agreements are not transferrable; new owners must secure an agreement by filing an interconnection request and submitting a fee of $50. (However, the interconnection will not need to be re-studied.) The standards include a provision for mutual indemnification and a weak process for dispute resolution.

The NCUC established a fee structure for interconnection applications: $500 for filing a pre-applicaiton report request;  $100 for generators up to 20 kW; $750 for generators larger than 20 kW but not larger than 100 kW; and $1000 for generators larger than 100 kW but not larger than to 2 MW. The FERC fee structure applies to the interconnection of systems over 2 MW. Additionally, systems in the Study Process must pay a deposit of $20,000, plus $1 per kW-AC, not to exceed $100,000.

Addition of Energy Storage

Existing solar PV systems can be upgraded in the DC system that does not impact the maximum generation capacity, daily production profile, or the proposed AC configuration of the generation facility including- DC optimizers, DC-DC converters, DC charge controllers, power plant controllers, and energy storage devices that the output is delivered during the same periods and with the same profile considered during the System Impact study- will not be considered a material modification and will not need to re-enter the interconnection queue. Other changes to the system might be considered as material modification to the system, and be required to re-enter the interconnection queue.  

Click here for Duke Energy Carolinas' website for interconnection, or here for Duke Energy Progress's, website for interconnection.  

*The NCUC’s interconnection standards do not govern interconnection to municipal utilities or electric cooperatives.


Legislation enacted by North Carolina in August 2007 (S.B. 3) required the NCUC to establish interconnection standards for distributed generation systems up to 10 MW in capacity. The law stated that the commission “shall adopt, if appropriate, federal interconnection standards.” This law also established North Carolina’s Renewable Energy and Energy Efficiency Portfolio Standard (REPS).

Program Overview

Implementing Sector: State
Category: Regulatory Policy
State: North Carolina
Incentive Type: Interconnection
Web Site:
Start Date:
Eligible Renewable/Other Technologies:
  • Solar Thermal Electric
  • Solar Photovoltaics
  • Wind (All)
  • Biomass
  • Municipal Solid Waste
  • Combined Heat & Power
  • Fuel Cells using Non-Renewable Fuels
  • Landfill Gas
  • Wind (Small)
  • Hydroelectric (Small)
  • Anaerobic Digestion
  • Fuel Cells using Renewable Fuels
  • Other Distributed Generation Technologies
  • Microturbines
Applicable Utilities: Investor-owned utilities
System Capacity Limit: No limit specified
Standard Agreement: Yes
Insurance Requirements: Varies by system size and/or type; levels established by NCUC
External Disconnect Switch: Not required for inverter-based systems up to 10 kW; utility's discretion for all other systems
Net Metering Required: No


Name: NCUC Order, Docket No. E-100, Sub 101
Date Enacted: 05/15/2015
Effective Date: 05/15/2015


Name: Consumer Services
Organization: NCUC Public Staff
Raleigh NC
Phone: (866) 380-9816

This information is sourced from DSIRE; the most comprehensive source of information on incentives and policies that support renewables and energy efficiency in the United States. Established in 1995, DSIRE is operated by the N.C. Clean Energy Technology Center at N.C. State University.