Interconnection Standards (Iowa)

From Open Energy Information

Last modified on February 12, 2015.

Rules Regulations Policies Program

Place Iowa
Name Interconnection Standards
Incentive Type Interconnection
Applicable Sector Agricultural, Commercial, Fed. Government, Industrial, Institutional, Local Government, Nonprofit, Residential, Schools, State Government
Eligible Technologies Anaerobic Digestion, Biomass, CHP/Cogeneration, Geothermal Electric, Hydroelectric, Landfill Gas, Municipal Solid Waste, Photovoltaics, Solar Thermal Electric, Wind
Active Incentive Yes
Implementing Sector State/Territory
Energy Category Renewable Energy Incentive Programs
Applicable Utilities Investor-owned utilities, Linn County REC

External Disconnect Switch Utility's discretion

Insurance Requirements Vary by system size and/or type; levels established by IUB

Net Metering Required No

Standard Agreement Yes
System Capacity Limit 10 MW*

Date added to DSIRE 2003-06-18
Last DSIRE Review 2013-02-04

References DSIRE[1]


Different rules govern the interconnection of distributed generation facilities in Iowa, depending on whether or not the interconnection is with a utility whose rates are regulated by the Iowa Utilities Board (IUB). Rate regulated utilities include only the state's two investor-owned utilities -- MidAmerican Energy and Interstate Power and Light (IPL) -- and Linn County Rural Electric Cooperative. The rates of municipal utilities and other rural electric cooperatives are not regulated by the IUB. In reality, only very limited guidelines are in place for utilities that are not rate-regulated by the IUB and since many details are left to the discretion of the utility, it is debatable whether these minimal provisions can be described as standards. The detailed standards for rate-regulated utilities adopted in May 2010 are described first below, followed by those that apply to both rate regulated and non-rate regulated utilities.

Net metering is also to available customers of investor-owned utilities for renewable energy facilities of up to 500 kW. Click here for information on net metering in Iowa.

Rate-Regulated Utilities Iowa's detailed interconnection standards apply to distributed generation facilities of up to 10 megawatts (MW)* that are not subject to the interconnection requirements of the Federal Energy Regulatory Commission (FERC), the Midwest Independent Transmission System Operator, Inc. (MISO), or the Mid-Continent Area Power Pool (MAPP). The definition of a distributed generation facility includes qualifying facilities (QFs) under the U.S. Public Utilities Regulatory Policy Act (PURPA) and alternative energy production (AEP) facilities as defined by Iowa law. AEP facilities are defined as electricity generation facilities which derive at least 75% of their energy input from solar, wind, waste management, resource recovery, refuse-derived fuel, agricultural crops or residues, or wood burning; as well as dam-based hydroelectric facilities. The rules are contained in IAC § 199-45 adopted by the IUB in May 2010.

Like many recent interconnection regulation adoptions in other states, the Iowa rules set four levels of review for interconnection requests. A project must meet all of the requirements of a given classification in order to be eligible for that level of expedited review. The level of review required is generally based on system capacity, whether system components are certified by a nationally recognized testing laboratory (NRTL), and whether the system is connected to a radial distribution circuit or to an area network. The basic definitions for each tier are as follows (see IAC § 199-45 for further details):

  • Tier 1: Lab-certified, inverter-based systems with a capacity rating of 10 kilowatts (kW) or less.
  • Tier 2: Lab-certified systems with a capacity rating of 2 MW or less, connected to a radial distribution network or a spot network serving one customer.
  • Tier 3: Lab-certified, inverter-based systems with a capacity rating of 50 kW or less which are connected to an area network and which will not export power; or lab-certified, non-exporting systems connected to a radial distribution circuit where the aggregate total of all generator nameplate capacity is no more than 10 MW (including the distributed generator applicant).
  • Tier 4: Systems with a capacity of 10 MW or less that do not meet the criteria for inclusion in a lower tier, including all systems using non-lab-certified components and those that require additional construction by the utility in order accommodate the facility.

The rules adopt IEEE 1547-2003 as the technical standard for evaluating interconnection requests. Systems are considered to be lab-certified if the equipment has been tested successfully in accordance with IEEE 1547.1, or certified as compliant with UL-1741, by a nationally recognized testing laboratory (NRTL). The rules also specify the technical screens which may be applied to applications at each level of review as well as time limits for different stages of the evaluation process. Generally speaking, higher level applications are subject to more intensive screening and longer time limits.

A lockable external disconnect switch (EDS) may be required at the utility's discretion, and the utility is permitted to make reasonable system monitoring and control requirements for systems larger than 1 MW. In addition, systems with a design capacity of 100 kW or less must be equipped with a device that automatically disconnects the system from the electric grid upon a loss of utility-supplied voltage.

The rules require the use of standardized interconnection applications and agreements, which have been developed by the IUB. The Level 1 application and agreement is a simplified version of the documents used for Level 2-4 interconnections. All applicants are required to carry and provide proof of some type of general liability insurance as part of the interconnection agreement. For facilities of less than 1 MW, homeowner's insurance is referred to by the rules as one acceptable form of general liability insurance without any specific minimum amount of coverage. For facilities of 1 MW or larger, the customer must maintain a general liability insurance policy with a limit of at least $2 million per occurrence and at least $4 million in aggregate, which also names the utility as an additional insured party.

Application fees are set at $50 for Level 1 applications; $100 plus $1 per kW for Level 2 applications; $500 plus $2 per kW for Level 3 applications; and $1,000 plus $2 per kW for Level 4 applications. Utilities are required to designate a point of contact for system interconnections and provide contact information on the utility web site.

Rate-Regulated and Non-Rate-Regulated Utilities Until the May 2010 adoption of detailed standards for rate regulated utilities, interconnection rules in Iowa were limited to those contained in IAC § 199-15.10. As with newly adopted Chapter 45, these rules were and are limited to PURPA QFs and AEP facilities. The contents of 15.10 largely address only power quality and safety issues, including: the use IEEE 1547-2003 as the technical standard for interconnection evaluations; allowing utilities discretion to require the installation of an EDS; a requirement that facilities of 100 kW or less have automatic disconnect capability upon the loss of grid voltage; granting utilities site access rights for inspection and testing; and allowing utilities to disconnect facilities in emergency situations. This rule was amended in May 2010 to update certain technical references and standards and harmonize it with new Chapter 45.

Beginning January 1, 2013, all AEP facilities must provide advanced notice of facility construction or installation. Facilities that will be attached directly or indirectly to an electric transmission or distribution line in a public utility's service territory must provide the utility with at least 30 days notice prior to the commencement of construction or installation. Facilities with a power purchase agreement with the utility are exempt from this requirement.

History In July 2006, the IUB began an inquiry into the development of uniform, detailed interconnection standards. A draft version of model interconnection procedures was issued for comment in April 2007, and in December 2008 additional comments were requested on the possibility of adopting interconnection rules similar to those adopted by Illinois. The IUB subsequently opened a formal rule making docket (RMU-2009-0008) in September 2009, using the Illinois rules as a starting point. After a series of further stakeholder consultations, final rules were adopted in May 2010.

*The actual language of the rules states generation capacity in terms of MVA or kVA, as opposed to MW or kW. In addition, while the standard rules only apply to systems up to 10 MW, they state that interconnection of larger facilities should take place using the Level 4 review process and agreement as a starting point, supplemented with mutually agreed upon modifications on the part of the customer and the utility.

Incentive Contact

Contact Name Duane Fournier
Department Iowa Utilities Board
Address 1375 E. Court Avenue
Place Des Moines, Iowa
Zip/Postal Code 50319
Phone (515) 725-7315


Authorities (Please contact the if there are any file problems.)

Authority 1: IAC § 199-15.10

Authority 2: IUB Order, Docket No. RMU-2009-0008
Date Effective 2010-07-21
Date Enacted 2010-05-26

Authority 3: Iowa Code § 476.6A
Date Effective 2013-01-01
Date Enacted 2012-03-29

  • Incentive and policy data are reviewed and approved by the N.C. Solar Center's DSIRE project staff.[1]


  1. 1.0 1.1  "Database of State Incentives for Renewables and Efficiency (DSIRE)"