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Studies and Reports > 2015 MN Biennial Report > Transmission Studies

Transmission Projects Report 2015
Chapter 3: Transmission Studies

3.0 Transmission Studies

3.1 Introduction

The Minnesota Public Utilities Commission requires that the utilities include in each Biennial Report a "list of studies that have been completed, are in progress, or are planned that are relevant to each of the inadequacies identified" in the Report.  Minn. Rules part 7848.1300, item F.  Since the 2011 Biennial Report, the utilities have broken this chapter up into several subsections, each addressing different types of studies.  The same arrangement for reporting the studies is continued in this 2015 Report.

Section 3.2 describes a number of studies that have been completed that either address expansion of the transmission network to provide for generation expansion, in particular renewable energy, or address local inadequacy issues (noted with a Tracking Number).  Section 3.3 describes ongoing regional studies that focus on expansion of the bulk electric system to address broad regional reliability issues and support expansion of renewable in the upper Midwest.  Section 3.4 focuses on ongoing load serving studies that are attempting to resolve local inadequacy issues.  Section 3.6 is a new section describing certain studies at the national level that are underway.

The MPUC rules state that the utilities must include in the Biennial Report a copy of "the most recent regional load and capability report of the Mid-Continent Area Power Pool" (MAPP).  Minn. Rule part 7848.1300, item B.  As the utilities reported in the 2011 Report, however, the Midcontinent Independent Transmission Operator (MISO) has taken over most of the planning that occurs in this part of the country.  MAPP has not prepared a Load & Capability Report since May 2009.  MAPP, in fact, discontinued its existence in October 2015. 

3.2 Completed Studies

The following studies were completed since the last Biennial Report was submitted in November 2013.  Previously completed studies can be found in previous Biennial Reports and are not repeated here.  Where specific transmission projects have been identified, a Tracking Number is provided.  The Tracking Number identifies the year the project was first considered for inclusion in a Biennial Report and the zone where the project is located.

Study Title

 Year Completed

Utility Lead


Austin Area Load Serving Study



An Austin Area Transmission Study was conducted to investigate different alternatives for increasing load serving capability in the Austin area.  The study identified two alternatives as the best options for increasing load serving capability and for satisfying reliability requirements. The preferred option is the construction of a new 161/69 kV substation in northwest Austin, MN. Tracking Number 2011-SE-N5.

Magnetation Plant 4 System Impact Study



System impact of Magnetation Plant 4; Canisteo Project (2013-NE-N5)

Polymet System Impact Study



System impact of new Polymet loads; Dunka Road Substation (2011-NE-N5) & Hoyt Lakes Substation Modernization (2013-NE-N19)

Buffalo Transformer Sizing Study



The Buffalo 345 kV transformer is in need of more capacity due to N-1 contingencies in the area and has been approved as part of MTEP project 3481. This study was performed to identify the appropriate transformer size at Buffalo.

Otter Tail Power Ten Year Plan



The Otter Tail Power Ten Year Plan summarizes the limitations to the OTP system within the next ten years and is intended to be refreshed biennially. This study refreshed project need dates and is based from conclusions of past completed group of Long Range Plans and the OTP High Voltage study.

Twin Cities Fault Current Analysis



A study was performed around the Twin Cities metro area to determine fault current levels for existing substations.  Black and Veatch were hired as a consultant to perform the work under NSP Transmission Planning staff supervision.  Several substation deficiencies were identified in the Twin Cities Metro Area.  These issues have identified fixes that will be implemented to reduce the amount of available fault current.

Out-Year Interconnection System Impact Study of MPC01200



Minnkota performed the Out-Year Interconnection System Impact Study of MPC01200. It was completed on December 26, 2014. Minor thermal and voltage upgrades were required to increase the capacity of the interconnection facilities, and one third party transformer upgrade was identified. The System Impact Study report is posted at www.minnkota.com.

Zemple 230 kV Substation Study Update



Evaluate the performance of the MP 115 kV system and the GRE 69 kV system during various outages associated with the new Zemple 230/115 kV Substation; Zemple 230 kV Project (2009-NE-N2)

New Tie Line Loop Flow Impact Study



Study Intended to capture and compare the impact of a new 500 kV Manitoba - United States tie line on the North Dakota - Manitoba loop flow phenomenon; Great Northern Transmission Line (2013-NE-N13)

GNTL Series Compensation and Reactive Resource Optimization



Joint study between MP and Manitoba Hydro intended to identify the recommended location and percentage of the proposed series compensation station as well as the location and size of shunt reactive devices required to control system voltages; Great Northern Transmission Line (2013-NE-N13)

System Impact Study of TSR #81022904



Minnkota performed the System Impact Study of TSR #81022904. It was completed on April 21, 2015. Two Minnkota transmission lines were impacted in the study and must be uprated in order to grant the request Transmission Service, including the Jamestown – Buffalo 345 kV line and the Square Butte – Center 230 kV line. Facilities Studies are underway.  A third party constraint was also identified, but was subsequently dismissed due to an incorrect rating assumption.  The System Impact Study report is posted on Minnkota's OASIS site.

Minnesota Transmission Assessment and Compliance Team 2015 Transmission Assessment (2015 – 2025)



This report is an annual transmission assessment investigating near-term, mid-term, and long-term transmission conditions.  This purpose of this study is to develop an understanding of the transmission system topology, behavior, and operations to determine if existing and planned facility improvements meet NERC Transmission Planning Standards TPL-001 through TPL-004.

Clearbrook Area Transmission Study ("Clearbrook Looped Service Study")



Minnkota participated in a study that evaluated the current load serving capabilities and future transmission needs in the area around Clearbrook, MN. The study was prompted by three things: pending load growth within the area, a neighboring utility's initiative for looped service, and opportunities created by planned transmission lines out of Clearbrook.  A new 230/115 kV substation near Bagley (referred to as Bagley West) and 115 kV transmission line to a location sixteen miles away (referred to as Clearbrook West) was evaluated against some alternatives. It ultimately was the favored option for meeting the stated needs.  Additional details can be found in Forms 1 and 2 or in the study report ("Clearbrook Looped Service Study" written by Otter Tail Power Company).

GNTL Analysis



Joint study between MP and Manitoba Hydro intended to evaluate the steady state and dynamic performance of the GNTL under a variety of system conditions; Great Northern Transmission Line (2013-NE-N13)

Shutdown of Taconite Harbor Generation System Impact Study



System impact of shutting down Taconite Harbor units 1 and 2 and evaluation of transmission solutions for maintaining and improving the reliability of the system should it become necessary or preferable to shut down Taconite Harbor units 1 and 2; the following projects were evaluated (or re-evaluated) as part of the study: Dunka Road Substation (2011-NE-N5); Embarrass Transformer (2013-NE-N8); Hoyt Lakes Substation Modernization (2013-NE-N19); Hat Trick 115 kV Project (2015-NE-N8); Minntac 230 kV Bus Reconfiguration (2015-NE-N10); Forbes 230/115 kV Transformer Addition (2015-NE-N11)

3.3 Regional Studies

While every study that is undertaken adds to the knowledge of the transmission engineers and helps to determine what transmission will be required to address long-term reliability and to transport renewable energy from various parts of the state to the customers, some studies are intentionally designed to take a broader look at overall transmission needs.  Regional studies analyze the limitation of the regional transmission system and develop transmission alternatives that support multiple generation interconnect requests, regional load growth, and the elimination of transmission constraints that adversely affect utilities' ability to deliver energy to the market in a cost effective manner.  Many of these studies are especially important for focusing on transmission needs for complying with upcoming Renewable Energy Standards.

3.3.1 MISO Transmission Expansion Plans

The Midcontinent Independent System Operator (MISO) engages in annual regional transmission planning and documents the results of its planning activities in the MISO Transmission Expansion Plan (MTEP).  The MTEP process is explained in detail in chapter 6 since the latest MTEP reports are being relied on to provide information about the transmission inadequacies identified in this Report.  Earlier MTEP Reports were summarized in past Biennial Reports.  For convenience, the following brief description of the latest MTEP reports is presented here.  The MISO Expansion Plans are available on the MISO webpage. Visit http://www.misoenergy.org and click on "Planning."

MTEP13 Report

The 2013 MISO Transmission Expansion Plan was approved by the MISO Board of Directors in December 2013.  The MTEP13 Report identifies those projects required to maintain reliability for the ten year period through the year 2023 and provides a preliminary evaluation of projects that may be required for economic benefit up to twenty years in the future. 

On the first page in the Executive Summary, MISO states that MTEP13 recommends 317 new projects totaling $1.48 billion of investment in transmission. Since the first MTEP cycle that closed in 2003, transmission investment totaling $17.9 billion has been approved, $6.2 billion of which is associated with projects already in-service.

MTEP14 Report

The 2014 MISO Transmission Expansion Plan was approved by the MISO Board of Directors in December 10, 2014.  The MTEP14 Report identifies those projects required to maintain reliability for the ten year period through the year 2024 and provides a preliminary evaluation of projects that may be required for economic benefit up to twenty years in the future. 

On the first page in the Executive Summary, MISO states that MTEP14 recommends 369 new projects totaling $2.5 billion of investment in transmission. Since the first MTEP cycle that closed in 2003, $7.4 billion of projects have been completed.

The MISO Expansion Plans are available on the MISO webpage. Visit http://www.misoenergy.org and click on "Planning."

MTEP15 Report

The 2015 MTEP report will be the 12th edition of this publication.  The report exists in draft form now but should be formally approved by MISO by the end of the calendar year. 
According to the MTEP15 Executive Summary, the MISO staff is recommending approval of 2.6 billion dollars of new transmission expansion projects through 2024, comprising 357 new projects.  The projects identified in the MTEP15 Report will support both reliability needs and congestion relief of the transmission system throughout the MISO system.

3.3.2 Manitoba Hydro-Electric Board Transmission Service Request

MISO continues to process generation interconnection requests and transmission service requests (TSRs) on the transmission system that they operate.  One group of these TSRs that involves the construction of new transmission in Minnesota consists of an increase in the ability to transfer power from Manitoba to the United States.  The original Manitoba Hydro TSRs requested delivery totaling 1,100 MW from Manitoba Hydro to four TSR customers in the United States (north to south) and 1,100 MW from utilities in the United States to Manitoba Hydro (south to north).  An initial System Impact Study was completed in June 2009 for Firm Point-to-Point Transmission Service between Manitoba Hydro and the TSR customers.  The initial study considered several 500 kV transmission options for increasing the capability of the Manitoba – United States interface by 1,100 MW flowing north or south.  A follow-up System Impact Study completed in April 2010 specifically evaluated the impact of a new 500 kV interconnection from the Winnipeg area to the planned CapX Bison Substation near Fargo, North Dakota.

More recently, MISO conducted a series of sensitivities on the Bison option to evaluate alternative transmission scenarios for achieving 250 MW, 750 MW, or 1,100 MW of increased transfer capability from Manitoba to the United States.  The initial MH-US TSR Sensitivity studies included a "Western Option" extending new 500 kV transmission to the Fargo-Moorhead area in western Minnesota, an "Eastern Option" extending new 500 kV transmission to the Iron Range in northeastern Minnesota, and a "230 kV Option" extending new 230 kV transmission to the Iron Range.  These initial sensitivity studies were completed in July 2013, but no action was taken upon them by the TSR customers at that time.

The final MH-US TSR Sensitivity Analysis evaluated the impact of building new 500 kV transmission from Winnipeg to the Iron Range in order to facilitate up to 883 MW of increased Manitoba to United States transfer capability.  After completion of this study by MISO in May 2014, the remaining TSR customers and MISO executed a Facilities Construction Agreement (FCA) for the "Great Northern Transmission Line," setting forth the ownership and financial responsibilities for the Project, among other terms.  Upon approval of the FCA by the FERC on November 25, 2014 in FERC Docket No. ER14-2950, MISO considered the Project an approved project under the MISO tariff and moved the Great Northern Transmission Line Project to Appendix A of the MISO Transmission Expansion Plan 2014 (MTEP14).  More information about the Great Northern Transmission Line Project can be found in Section 6 under project 2013-NE-N13 (MTEP ID #3831) and in MPUC Docket No. E015/TL-14-21.

3.3.3 MISO Northern Area Study

The Northern Area Study found that large-scale regional transmission expansion in MISO's northern footprint (North Dakota, Minnesota, Northern Wisconsin, Michigan Upper Peninsula, and lower Michigan) is not cost-effective based on production cost savings, under current business as usual conditions.  Economic benefits for MISO from new potential Manitoba Hydro to MISO tie-lines could be realized with minimal incremental transmission investment.  The Northern Area Study identified a Hankinson – Wahpeton 230 kV & Big Stone – Morris 115 kV upgrade as a cost-effective option to mitigate the remaining out-year congestion from wind on the Dakotas – Minnesota border (resultant benefit to cost ratio B/C ratio 3.46 – 14.74 depending on scenario assumption).  The Hankinson – Wahpeton 230 kV & Big Stone – Morris 115 kV option is being further analyzed in the Market Efficiency Planning Study.  The Northern Area Study makes no conclusions regarding the broader multi-value benefits that might be achieved, or the need for future localized reliability upgrades.

For the complete report please use the following link and go to the section called Northern Area Study.


3.3.4 Manitoba Hydro Wind Synergy Study

The variable and non-peak nature of wind creates integration challenges within MISO.  Manitoba Hydro, with its large and flexible system, offers potential solutions for meeting these challenges.  At the prompting of Manitoba Hydro and the potential customers of output from their new hydroelectric dams, MISO conducted the Manitoba Hydro Wind Synergy Study to evaluate whether the cost of expanding the transmission capacity between Manitoba and MISO would enable greater wind participation in the MISO market.  The study, which was done under full MISO stakeholder review, was completed in 2013.  The Manitoba Hydro Wind Synergy Study found significant benefits can be realized from the addition of either an eastern 500 kV line between Winnipeg, Manitoba, and Duluth, Minnesota, or a western 500 kV line between Winnipeg, Manitoba, and Barnesville, Minnesota.  Maps of the two alternative routes for a 500 kV line from Winnipeg are shown below.  The study also found that expanding the External Asynchronous Resource (EAR) structure from unidirectional to bidirectional would provide near-term benefits as well as long-term benefits.  Below is a link to the study:

https://www.misoenergy.org/Library/Pages/Results.aspx?q=manitoba hydro wind synergy

East Option: Dorsey to Blackberry
- 500kV line from Winnipeg to Grand Rapids
- 345kV double circuit line from Grand Rapids to Duluth

West Option: Dorsey to Fargo/Moorhead Area
- 500kV line from Winnipeg to Fargo/Moorhead Area
- 345kV line from Fargo/Moorhead to Monticello

3.3.5 Market Efficiency Planning Study

As described in the 2013 Biennial Report, MISO conducts a Market Efficiency Planning Study (MEPS) as part of its ongoing planning process.  The purpose of the MEPS is to determine whether there are transmission projects that could remove transmission constraints and thus more efficiently use available generation resources.  The MEPS results are reported as part of the annual MTEP report.

During the MEPS process, projected economic and power flow models are developed which, when analyzed, determine the total production costs that are incurred to provide energy to the MISO load. Transmission constraints, which are the transmission elements that limit the amount of power that can be transferred between the unused, lower-cost generation and the load, are identified.

Through a stakeholder discussion, transmission projects are proposed which could mitigate the constraints.  The costs for these proposed transmission projects are determined and compared to the amount of production cost savings that could be realized if those projects were in service.  The resultant benefit to cost (B/C) ratio of the projects indicates whether the proposed solutions should be considered for further evaluation for constructability and reliability analysis.  Stakeholder review and comments are compiled and a decision on whether to recommend a MEPS project be included in the upcoming MTEP report is made.

3.3.6 Minnesota Renewable Energy Integration and Transmission Study (MRITS)

In 2013 the Minnesota Legislature directed MN electric utilities and transmission companies and other load serving entities to "conduct an engineering study of the impacts on reliability and costs of, and to study and develop plans for the transmission network enhancements necessary to support increasing the renewable energy standard established in Minnesota Statutes § 216B.1691, subdivision 2a, to 40 percent by 2030, and to higher proportions thereafter, while maintaining system reliability."  Minn. Laws 2013, chapter 85, article 12, section 4(a).  The Minnesota electric utilities and transmission companies, in coordination with MISO, conducted the engineering study, which came to be called the Renewable Energy Integration and Transmission Study (MRITS).  The Department of Commerce directed the study and appointed and led a Technical Review Committee (TRC).  The final study includes: 1) A conceptual plan for transmission for generation interconnection and delivery and for access to regional geographic diversity and regional supply and demand side flexibility, and 2) Identification and development of potential solutions to any critical issues encountered.  The MRITS Report was submitted to the MPUC by the Minnesota Department of Commerce on November 5, 2014, under Docket Number E999/CI-13-486.  The Report is also available at the following link:


All utilities with Minnesota retail electric sales and all Minnesota transmission companies participated in the study.  Eight Balancing Authorities were represented and over 85% of the Minnesota retail sales were in the four largest Balancing Authorities: Xcel Energy (NSP), Great River Energy, Minnesota Power, and Otter Tail Power.  The study area is within the NERC reliability region Midwest Reliability Organization (MRO).  Nearly all of the Minnesota retail sales are within the Midcontinent Independent System Operator (MISO).  The Balancing Authorities within MISO, including the Minnesota BAs, are functionally consolidated.

The authors of the study describe the Study Objectives at page 1-2 of the Executive Summary as follows:

  1. Evaluate the impacts on reliability and costs associated with increasing Renewable Energy to 40% of Minnesota retail electric energy sales by 2030, and to higher proportions thereafter;
  2. Develop a conceptual plan for transmission necessary for access to regional geographic diversity and regional supply and demand side flexibility;
  3. Identify and develop options to manage the impacts of the renewable energy resources;
  4. Build upon prior wind integration studies and related technical work; coordinate with recent and current regional power system study work;
  5. Produce meaningful, broadly supported results through a technically rigorous, inclusive study process.

The MRITS study, perhaps, provides the most pertinent information about the ability of the existing transmission grid to respond to increased levels of renewable energy and the challenges and costs involved in upgrading the grid going forward.  The authors state "The study is focused on the reliability of increased levels of variable renewables (wind and solar generation) and the associated costs of those impacts."  Executive Summary at p. 1-2.

3.3.7 MISO Clean Power Plan (CPP) Study

The study is designed to provide a robust and reasonably realistic representation of a world in which the EPA's draft Clean Power Plan (CPP) is fully implemented.  Scenarios are derived and implemented to capture a wide range of compliance strategies without leaving the bounds of the draft rule.  Implementation of the draft rule will take the form of capacity additions and retirements coupled with constraints representing the EPA's CO2 rate targets on state, sub-regional and regional levels.  In order to account for the limitations and feedback from the natural gas industry a new gas model has been added to the more traditional electric model.  This novel approach will provide unique insights into how the electric and gas systems will interact with each other under CPP implementation.

The study consists of both reliability analysis, using PSS/E, and production cost analysis, using PLEXOS.  These models were chosen because of MISO's experience with them in past analyses, along with their ability to meet the needs of this study.  The study endeavors to create similar representations of the underlying infrastructure and use similar regulatory and economic assumptions in both models.

There are six scenarios being studied.

  1. Business-as-Usual (BAU)
  2. CPP Constraints (CPP)
  3. Coal-to-Gas Conversions (C2G)
  4. Gas Build-Out (GBO)
  5. Gas, Wind and Solar Build-Out (GWS)
  6. Increased Energy Efficiency with Wind and Solar Build-Out (EWS)

    3.3.8  Eastern Interconnection Planning Collaborative

The Eastern Interconnection Planning Collaborative was described in detail in both the 2011 and the 2013 Biennial Reports.  In December 2011, the EIPC Phase 1 Report was completed.  Phase 1 looked at the creation of a combined grid model for the Eastern Interconnection and the formation of a diverse Stakeholder Steering Committee. 
This Stakeholder Steering Committee chose three future scenarios as the basis for the Phase 2 work.  The three scenarios are:

  1. A Nationally Implemented Federal Carbon Constraint with Increased Energy Efficiency/Demand Response,
  2. A Regionally Implemented Renewable Portfolio Standard; and
  3. Business as Usual

On July 2, 2015, the Phase 2 final report associated with this effort was submitted to the U.S. Department of Energy.  That report is entitled Phase 2 Report:  Interregional Transmission Development and Analysis for Three Stakeholder Selected Scenarios and Gas-Electric System Interface Study.  It consists of 13 volumes.  The following is quoted from Phase 2 Report, Volume 2, at page 1-11.

Phase I of the project focused on developing the stakeholder processes, developing and specifying inputs for eight different futures and an additional seventy-two sensitivities, and identifying the generation resources (location, type and amount) and additional transfers needed to support the futures.  This effort involved stakeholders in direct and detailed conversations developing the futures and sensitivities and the many inputs needed for analysis.  Stakeholders were also directly involved in reviewing results and choosing the final three scenarios.

. . . .

The results of the Gas-Electric System Interface Study provide a comprehensive analysis across the region of the adequacy of the natural gas pipeline delivery system to meet the needs of gas-fired electric generation system under various conditions over a 10-year horizon.  In addition, the study identified constraints on the natural gas pipeline system that may affect the delivery of gas to specific generators following a variety of postulated gas and electric system contingencies.  The study also describes a number of mitigation measures that may be considered by gas and electric system operators to alleviate the impacts on the electric system under such conditions.  The results of this study provide a wealth of information for consideration by the Participating Planning Authorities and regional stakeholders to inform their respective operational and planning analyses. 

The entire Phase 2 Report is available on the Internet at www.eipconline.com.

3.4 Load Serving Studies

Load serving studies focus on addressing load serving needs in a particular area or community.  Since many of the inadequacies in Chapter 6 are load serving situations, many of these studies relate to specific Tracking Numbers.

Study Title

Anticipated completion

Utility lead for Study


Owatonna Area Study



Owatonna Area Study.  This study is to evaluate the need for more voltage support under contingency.  The early results are indicating an additional 161 kV line into the Owatonna area.  This study is still ongoing.

North Shore Loop Comprehensive Plan



Develop a comprehensive plan and staged approach for transmission expansion in the area between Duluth, Taconite Harbor, and Hoyt Lakes in light of future changes in generation and load; Projects TBD

Bear Creek 69/46 kV Transformer Addition



System impact of retiring Sandstone 69/46 kV source and establishing new Bear Creek 69/46 kV source; Bear Creek 69/46 kV Transformer (2015-NE-N13)