BSSE Transmission Line


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Frequently Asked Questions

Helicopter construction

What are the steps in the line stringing process?

  • Because conductor is too heavy for a helicopter to lift, the helicopter first carries a rope from the ground to the top of the structure.
  • Hovering between 30 and 80 feet from the structure, the helicopter sets the rope into the traveler, which looks like a pulley. The traveler has a trap door to allow the rope in but to prevent it from falling out, securing it in place.
  • The helicopter continues on to the next structure, pulling the rope as it goes.
  • After the helicopter installs the rope, crews connect the rope to the conductor. Crews then use a machine on the ground to pull the rope and set the conductor.


What is the schedule for stringing?

The helicopters will work their way west toward Aberdeen, South Dakota, then northwest toward Ellendale, North Dakota. The project team expects to complete stringing in October 2018.


Why use helicopters?

Transmission line projects have used helicopters to string transmission lines for more than 40 years. Using helicopters is more efficient and economical and safer than other options and minimizes ground impacts.


Is safety a concern?

We carefully take into account the weather, visibility, and other conditions that could interfere with working conditions. It’s simple. If conditions aren’t safe, we don’t work.

We encourage motorists who notice the helicopters at work to:

  • Focus on the road.
  • Maintain a safe speed.
  • Refrain from taking photos.
  • Stay a safe distance from crews.
Activity near transmission lines

May I hunt near the transmission line?

Yes, but be aware of the transmission line before aiming or firing a gun. Intentionally shooting a transmission line is illegal. Shooting insulators or conductors can break a wire or cause hazards such as an electrical discharge or arc flash.


Can I build a bonfire, burn leaves, or build another type of fire under the transmission line?

No. Never start a fire under the transmission line or within the right-of-way. Smoke and hot gases from fires can create a conductive path for electricity. A fire could damage the poles or wires and result in an outage. It’s possible that the transmission line could flash to the ground through hot air and smoke.


Can I ride my snowmobile under or near transmission lines?

As a landowner, you have the right to allow and restrict access to your land for snowmobiling. We don’t recommend that the transmission line right-of-way be used for snowmobiling and encourage snowmobilers to watch for utility poles, guy wires, fencing, and underground cable junction boxes. Remember that these dangers aren’t easily seen from a speeding snowmobile, especially in the dark.

Agriculture and land use

What farming practices are prohibited within the right-of-way?

We will not permit installation of structures, planting of tall-growing vegetation, and stock piling of crops under the transmission line.


Will I be able to farm around the structures?

Farming activities can occur within the right-of-way and adjacent to the structure pursuant to the easement. Additionally, our proposed offset from field lines for the portions of the route that are adjacent to roadways allows most landowners to use their largest equipment between the transmission structures and the road right-of-way. Most agricultural uses will have no impact.


Is it safe for livestock to graze under the transmission line?

Yes. Current scientific research shows no safety concerns or effects on production for livestock grazing under a high-voltage transmission line.


What impacts will the transmission line have to aerial sprayers?

Crop dusters are able to spray fields with transmission structures within or adjacent to them.  We will work with the Federal Aviation Administration (FAA) to meet requirements for airports and runways.


Will the new transmission line interfere with GPS auto-steering reception?

A GPS unit in farming equipment should work properly with a high degree of accuracy underneath the transmission line. GPS devices continually pull signals from a number of satellites, not just one. A signal may be blocked temporarily if the transmission structure is between the receiver and a weak satellite signal, but it will return as the farm equipment moves past the structure. It is also common for GPS receivers to drop and pick up signals even in the absence of transmission lines and structures. We can provide the transmission structures’ GPS points to landowners to help farm equipment navigate around structures.


What will happen to trees or buildings located within the right-of-way?

We will remove trees and buildings within the 150-foot-wide right-of-way to ensure safety. We also will trim or remove danger trees, or trees outside the right-of-way that lean toward the right-of-way or are tall enough to pose danger to the line, to reduce potential damage caused by falling limbs or trees. We’ll follow all federal and state regulation requirements. If you’re considering planting a tree near the right-of-way or already have trees on your property near the right-of-way, remember these safety tips:

  • Call one of the transmission line owners shown on the inside cover before planting any trees or shrubs near right-of-way.
  • Don’t plant trees or shrubs within the right-of-way.
  • Teach your children always to look up for the transmission line and explain why they shouldn’t climb trees near it.
  • If trees come in contact with the transmission line, immediately contact one of the transmission line owners shown on the inside cover or emergency personnel to safely remove them.
  • Call a professional to trim or remove trees that could come in contact with the transmission line.
  • Remember that even if trees look like they have adequate line clearance other factors change every day, like the weather causing the transmission line to stretch and sag.
  • The erection of any type of structure must be approved by the transmission line owners to ensure it’s compatible with the line.


May I construct a building or other structure beneath the transmission line?

Not without prior written approval from the transmission line owners. To avoid situations that create unsafe conditions for you and/or utility workers, buildings and other structures generally are not permitted within the right-of-way. Metal buildings near the line may need to be grounded.


I own a building near the transmission line. How might it be affected?

Large buildings or metallic objects near the right-of way could have an induced voltage due to EMF. The charge typically will drain through plumbing, building electrical service, framing, etc. If the charge doesn’t drain, it may result in nuisance shock. You can mitigate this by grounding the building or metallic object.Contact one of the transmission line owners with any shock-related problems or questions about grounding buildings or objects.


Can I safely refuel my machinery near the transmission line?

Keep a minimum distance of 100 feet from the line for refueling. If you must fuel a vehicle under a transmission line, as with any situation in which a portable fuel tank is used, use a fuel tank with a flame arrester. Both the vehicle and the fuel container should be grounded while fueling to reduce the risk of sparks.


What precautions should I take when irrigating near the transmission line?

If you irrigate near the transmission line it’s important to remember: • Never let a solid stream of water contact the transmission line.

  • Make sure your irrigation system is well grounded.
  • When unloading irrigation pipes, stay at least 50 feet from the transmission line to avoid raising them too close to the wires.
  • Install long lengths of metal pipe at right angles to the transmission line, if possible, to reduce risk of the pipes building up an induced voltage.
  • Take extra precautions when using fertilizers and pesticides because they increase water conductivity.

If you’re questioning whether your irrigation system is adequately grounded or you’re planning to install a new irrigation system, contact one of the transmission line owners.


How will the line impact center-pivot Irrigation systems?

A transmission line near a center-pivot irrigation system typically will span the outer arc of the center pivot arm to provide clearance at the end of the pivot arm to limit interference with irrigation operation.

Several factors determine the ability of the transmission line to span the outer arc of center-pivot irrigation system including the proximity and orientation of the pivot to the transmission line, the length and height of the center-pivot, and the terrain of the property.

We will work with landowners where center pivots exist to minimize impacts to center-pivot irrigation systems. If you plan to install a new center-pivot irrigation system, please contact one of the transmission line owners to discuss the location.


Will having this transmission line on my land preclude me from having wind turbines?

Having a transmission line on your parcel will not automatically preclude that land from wind development. This project will increase capacity for wind energy in North Dakota, South Dakota, and the region. Often, within a wind farm, there are parcels that contain both wind turbines and transmission lines that connect to the wind farm’s interconnection point.  Turbine placement depends on many factors, including setback distances from homes, structures and roads, as well as environmental and engineering siting considerations.  While a turbine would not typically be placed within the immediate vicinity (i.e. fall down distance) of a high-voltage transmission line, this setback is similar to or less than setbacks from many other features.

Engineering, construction, and maintenance

Will the new transmission line interfere with radio, television, cell phone, and GPS reception?

TV interference is unlikely but may occur if a transmission structure is between your receiver and a weak distant signal. Most reception is now digital, allowing for multiple paths to a signal.

Tansmission structures near satellite-based GPS farm equipment may block or reflect GPS signals like a building, but the presence of multiple GPS satellites usually prevents this from being a significant issue.

Transmission structures also can impact ground-based GPS, such as Real Time Kinematic (RTK) GPS, but this issue can be overcome by relocating the base station or using repeater stations.

Electric-field corona from a transmission line can produce radio frequency emissions, but these emissions generally are at a lower frequency than the frequencies used for GPS systems.


How will you keep the transmission line safe?

We’ll build and maintain the transmission line to meet or exceed safety standards specified by the National Electrical Safety Code (NESC) and the North American Electric Reliability Corporation (NERC). To keep the line safe, we don’t recommend refueling equipment under the transmission line and won’t permit new construction within the right-of-way. We designed the transmission line and line infrastructure to withstand extreme weather conditions.

Protective devices at line terminals stop the electricity flow under abnormal operating circumstances. Refer to the contact information on your easement agreement for activities we allow near the transmission line.


What is sag? And what is the height of the lowest sag?

Sag is the vertical drop from the structure attachment point to the lowest point of the wire curvature. The amount of sag varies with the wire tension, temperature, and distance between structures. The height above ground at the lowest point of the sag is determined through engineering analysis and may vary throughout the project. The minimum ground clearance will be about 30 feet above ground to the lowest point of the sag.



How will you maintain the right-of-way?

We anticipate very little maintenance for most of the transmission line. Landowners retain ownership of the property and can continue to use the right-of-way for agricultural purposes or other purposes that do not impact the safety of the transmission line system. We will inspect the line by air, with occasional visits by ground crews as needed.


How will you handle construction damage on my property?

During the construction phase, inspectors retained for the project will monitor and record damages when they occur. We will review each case and determine a course of repair. The responsibility and cost for any repairs belong to us.

>>View the construction/maintenance damage compenstation factsheet.


How will you deal with damage to roads?

During the construction phase, inspectors retained for the project will monitor and record damages when they occur. Likewise, the inspectors will monitor and record damages on public roadways. We will review each case and work with local authorities to determine a course of repair. The responsibility and cost for any repairs belong to us.

General project information

What is the Big Stone South to Ellendale project?

Big Stone South to Ellendale (BSSE) is a 160-170 mile transmission line project from the Big Stone South Substation near Big Stone City, South Dakota, to the Ellendale Substation near Ellendale, North Dakota. Otter Tail Power Company and Montana-Dakota Utilities Co. jointly own this project. Otter Tail Power Company is the project lead.


What are the BSSE project benefits?

Benefits to building BSSE include:

  • Increased system of the regional power system.
  • Increased transmission system capacity to address the growth of regional demand.
  • Support public policy by enabling renewable energy to be integrated in the system. 
  • Boost regional economies by creating jobs and supporting local businesses.


Who determined that the BSSE project was needed, and what was the process?

The Midcontinent Independent System Operator, Inc. (MISO) conducts transmission planning to ensure reliability across its footprint. The studies through this planning process result in recommendations for transmission upgrades. Several studies have been conducted including the Regional Generator Outlet Study, which started in 2008 and ended in late 2010. This study led to additional analysis to identify the projects that could provide benefits beyond meeting local energy and reliability needs.

These projects are called multi-value projects (MVPs) and will allow the grid to deliver reliability, public policy and economic benefits across the system. BSSE was approved as an MVP by the MISO Board of Directors in December 2011. The MVP projects will provide regional economic benefits by displacing higher-cost generation, reducing transmission losses and supporting regional wind integration while enabling access to low-cost energy in the MISO footprint.

>> View our MISO MVP factsheet


What is the BSSE timeline?

The BSSE transission line is anticipated to be in service by the end of 2019. A three-year construction process would begin in 2016. 

Health and safety

Should I be concerned about safety near a high-voltage transmission line?

No. BSSE will meet or exceed all National Electric Safety Code Standards. Additionally, Montana-Dakota Utilities Co. and Otter Tail Power Company will conduct studies for electric and magnetic fields (EMF) levels for the project. Several scientific organizations, including the American Medical Association, American Cancer Society, American Physical Society, and National Academy of Sciences, have stated that the body of EMF evidence, particularly magnetic fields, indicates that exposure to these fields does not present a human health hazard.

>> View our EMF factsheet


Will the substation or transmission line attract lightning?

Because they’re one of the tallest objects in the general vicinity, substations and transmission lines may attract lightning. However, a shield wire along the top of the structures provides protection from lightning strikes.


How do I stay safe if the transmission line falls during a storm?

If the transmission line falls, don’t touch anything in contact with it, stay far away, and immediately contact one of the transmission line owners shown on the inside cover or your local fire or police department. And if you’re in your house, unplug any appliances that may still be running.


What is EMF and is it harmful?

EMF stands for electric and magnetic fields. These fields are present wherever electricity is generated, transmitted, and used. These fields are found in nature. For example, the earth has a magnetic field that causes a compass to point north, and storms produce extremely high electric fields resulting in lightning. Electric and magnetic fields also are used by devices such as cell phones to transmit signals over long distances.

Electric fields are produced by the separation of opposing charge and magnetic fields are produced by the flow of charge (electric current).

Several scientific organizations, including the American Medical Association, American Cancer Society, American Physical Society, and National Academy of Sciences, state that EMF exposure does not present a human health hazard.


What is stray voltage? And does it pose a health threat?

Stray voltage is a situation in which voltage (or electric current) is present where not intended due to non-ideal operating conditions on the connected distribution system.

Stray voltage can pose a health threat to humans or animals if severe. However, transmission lines don’t create stray voltage because they don’t connect directly to businesses or residences. Stray voltage may be an issue from distribution lines because of the direct connection to the system to which it delivers power. We don’t expect stray voltage issues, however, we’ll take appropriate measures to address concerns on a case-by-case basis.


Will the transmission line impact pacemakers?

Transmission lines are only one of a number of sources of electromagnetic interference (EMI) that could interfere with a pacemaker. EMI is a disturbance in the operation of an electrical circuit due to electromagnetic fields emitted from an external source.

Medical research studies show a wide range of responses for the threshold at which pacemakers and other implanted devices responded to an external EMI source.

The exposure to EMF and, therefore, the potential for EMI directly beneath a 345-kV transmission line is no greater than that from some common household appliances. The main risk factors for medical devices include device sensitivity, distance from the source, and field strength and orientation.

Individuals with pacemakers should consult their physicians or implant manufacturers to determine whether their implants may be susceptible to electrical interference. If a person with a pacemaker is in an electrical environment and the pacemaker begins to produce a regularly spaced pulse that is not related to a normal heartbeat, the person should leave the environment and consult a physician.


What safety precautions should I take when using farm machinery and equipment near the transmission line?

When using farm machinery and equipment, always be aware of transmission line wires and guy wires. And although transmission line clearance is designed to accommodate most farm machinery and equipment, always remember:

  • Physical contact, including equipment, with a transmission line can be hazardous and may cause a lethal shock.
  • Don’t lift, elevate, build, or pass under a transmission line any object, tool, or vehicle that may contact wires.
  • To help prevent arc flash or electric shock, keep equipment, antennas, and people at least


Will nonelectric fencing pose a safety hazard near the transmission line?

Nonelectric fencing made of barbed wire or similar materials directly attached to steel posts are adequately grounded and will not collect an electric charge. Nonelectric metallic fencing installed on insulating posts such as wooden poles could have induced voltages if the fence is parallel to the transmission line.

An induced voltage occurs when electric charge accumulates on an otherwise neutral object due to electric and magnetic fields from a nearby energized object, such as a transmission line.

If you are planning to install a wire fence parallel to and near the transmission line, contact one of the transmission line owners shown on the inside cover to determine the distance required between grounding posts.

If you own a fence that is within 100 feet of the right-of-way, contact one of the transmission line owners shown on the inside cover to address possible mitigation of induced voltage.


Can electric fencing build up an electrical charge?

Although electric fencing is insulated from the ground, it still can pick up a charge from the transmission line. In most cases the charge will drain off when the DC charger unit is connected to the fence. However, a small shock may occur when the DC charger is disconnected for maintenance or when the fence is being built.

Some of the factors attributed to electrical charges in fencing include: • The length of fence paralleling the line.

  • The distance between the line and the fence.
  • The amount of moisture in the fence posts and the ground.
  • The presence of grounding devices such as metal fence posts or weeds growing next to the fence.

Follow these steps to mitigate electric fencing shock: • Short out one or more of the fence insulators to the ground with a wire when the charger is disconnected.

  • Install an electric filter to ground charges induced from the transmission line while allowing the DC charger to be effective.
  • Contact one of the transmission line owners if you have a problem or concern regarding induced voltage to fencing or other structures within 100 feet of the edge of the transmission line right-of-way.
Landowner easements and compensation

What is an easement?

An easement is the granting of the right for another person or party to use a specific portion of ones property for a specific purpose while retaining legal title to that property. For the BSSE project, an easement is acquired for a specific 150-foot right-of-way to build and maintain a transmission line.


What is the difference between standard and overhang easements?

Standard easements are used for property on which one or more structures will be installed within the easement. 

Overhang easements are used for property on which a portion of the 150’-wide easement would fall but on which structures will not be installed. The term overhang easement is used because a portion of the structure (cross-arms, insulators, conductors) may hang above a portion of the property.

Easement Image


How did the project determine land values for easement payment?

The project’s easement payments are based on land values determined by data gathered from recent sales within the routing area, as well as land values compiled for use by the National Agricultural Statistical Service.


Is the project offering a different payment for a standard easement versus an overhang easement?

Yes. A standard easement payment is more because a structure will be installed on the property. An overhang easement is less because a structure will not be installed on the property.


How is a project easement payment determined?

Each easement payment is calculated by multiplying the land value for land-use type(s) present within the easement footprint by the easement acreage, and again by the percentage paid for the type of easement being acquired. Land-use types are classified as crop land, pasture land or hay land.

The standard easement will be paid at 80% of the land value, whereas the overhang easement will be paid at 40% of the land value.

Easement Calculation


How are affected landowners compensated?

Right-of-way agents will prepare a specific estimate for each landowner based on a consistent payment formula. Total compensation for each easement varies, depending on factors such as the local market value of land, the calculated acreage for the right-of-way, current land use, and whether poles will be located in the easement.


Why do landowners receive a one-time payment instead of annual payments?

We will offer landowners a single payment to cover the cost of the easement footprint, structures on the property, and impact to agricultural operations. This approach follows the established compensation process for transmission lines within the region. Annual payments are traditionally associated with generation projects on private land. These assets generate a commodity that is marketed to the public. For example, wind farms usually make annual payments to landowners because they sell the energy generated on the landowner’s property. Often the payments fluctuate with the amount of energy being produced.

In comparison to generation projects, transmission lines are generally low impact to land use, with the greatest disturbance occurring during construction. During operation of the transmission line, the structures themselves will take approximately 0.01 acres per mile out of production.


How will I be compensated for crop damage during construction?

We will compensate landowners for crop damages that occur during construction. The damage payment for standing crops will be determined by the following formula: acres x yield x price per bushel. During the year construction is completed, project representatives and the landowner will jointly determine the acres of crop affected by construction. Reimbursement will be based on the average yield of the adjoining crops and prevailing price per bushel being paid by a comparison of values from local elevators or current contractual arrangement.

For the three consecutive years following construction, the project will make an additional payment for the potential of loss in crop yield based on this schedule:

  • Year 1 - 50% of the value of the crop damage payment agreed to during the construction season; 
  • Year 2 and Year 3 – 25% of the value of the crop damage payment agreed to during the construction season.
Project costs

How much will the BSSE project cost?

The project will cost about $293 million to $370 million.


Who will pay for BSSE?

BSSE will benefit the upper Midwest region. As a regional project, the cost will be allocated to MISO transmission customers. Otter Tail Power Company and Montana-Dakota Utilities Co. customers will pay about one percent of the cost.

Project owner and facilitator information

What is MISO?


The Midcontinent Independent System Operator, Inc. (MISO) is a non-profit, member-based organization that provides reliable, cost-effective electric systems and operations; dependable and transparent prices; open access to markets; and planning for long-term efficiency. It covers all or parts of 11 states and the Canadian province of Manitoba.

The transmission operator has developed a plan to expand the system to meet the needs of new generation and to open up transmission bottlenecks throughout areas of the MISO footprint. Otter Tail Power Company and Montana-Dakota Utilities Co. are members of MISO. MISO identified the need for the BSSE project and Otter Tail Power Company and Montana-Dakota Utilities Co. serve the majority of customers within the MISO project area, making these two companies well suited to develop, own, and operate the new transmission line.


Who are Montana-Dakota Utilities Co. and Otter Tail Power Company?


Otter Tail Power Company provides electricity and energy services to about 130,000 customers in a 70,000 swuare-mile area of northeastern South Dakota, eastern North Dakota, and west central Minnesota. Otter Tail Power Company is a subsidiary of Otter Tail Corporation.



Montana-Dakota Utilities Co. distributes natural gas, generates, transmits and distributes electricity, and provides related services in the northern Great Plains. The company serves approximately 130,000 electric customers and 245,000 natural gas customers in 262 communities in North Dakota, South Dakota, Montana and Wyoming. Montana-Dakota is a division of MDU Resources Group, Inc.


Regulatory process

How did you determine where the transmission line will be located?

The project team identified the preferred route using input gathered from the public at routing meetings along with agency input and environmental and engineering considerations. For more information, please refer to the summary outreach document located on the Routing page.


How far will your transmission line be from homes?

No homes will be located within our right-of-way, which is 150 feet wide. This means the minimum distance a home could be from the centerline of our project is 75 feet. In addition, we adopted a goal to minimize the number of homes within 500 feet of the project centerline.


What permits and approvals are required before BSSE can be constructed?

Otter Tail Power Company and Montana-Dakota Utilities Co. will file necessary applications with the appropriate regulatory commissions when a preferred route is determined

BSSE will need additional permits/approvals from other state and federal agencies after a route is established. These agencies include the U.S. Army Corps of Engineers (particularly for river crossings and impacts to jurisdictional waters) and the South Dakota Department of Environment and Natural Resources and North Dakota Department of Health for National Pollution Discharge Elimination System permitting. The project will also coordinate construction activities with counties and cities.

Soybean Cyst Nematode (SCN)

For detailed information about SCN, we encourage you to read this 2013 report published by South Dakota State University (SDSU)’s Department of Plant Science.

We worked with SDSU’s Department of Plant Science to develop a sampling methodology, to test soil samples for SCN, and to identify techniques to reduce the spread of SCN during survey work and construction.

What is SCN?

SCN was first found in South Dakota in 1995. SCN damages soybeans and reduces yields by robbing the plants of nutrients, stunting or dwarfing the plant roots, reducing the number and efficiency of nitrogen fixing nodules, and providing wounds for other pathogens to enter roots.

I’m a landowner on the route:

When did you test my land for SCN? How will you use the results?

In fall 2014 and spring 2015 we sampled and tested soil samples for SCN as a condition in the South Dakota Public Utilities Commission’s permit for the project. We’ll use the results to identify parcels of land that have SCN present and, therefore, will guide techniques to minimize the spread of SCN during the line’s survey work and construction.

Our testing was limited to the project’s right-of-way. If your results are negative, SCN was not detected in the locations that we sampled—but SCN may be present in other areas of your parcel. If your results are positive, SCN may be present in different quantities in other areas of your parcel.

Will construction of the line spread SCN on my land?

Farm practices, flood water, and wildlife such as migrating birds, can spread SCN. Because of these other methods by which SCN can spread, the techniques we use during construction will only reasonably minimize—not stop—the spread of SCN.

My land tested positive for SCN. What management practices can I do to mitigate the spread of SCN?

These management suggestions are outlined in your results letter and discussed in more detail in the SDSU report mentioned above.

Someone rents and farms land that I own. Do I need to share the SCN results?

We encourage you to share these results with your tenant; however, it is your choice. We will not share results directly with your tenant.

I rent land on the route:

How do I obtain test results?

We sent SCN results to landowners. You must contact the landowner to view the results.

Public Meeting Materials

Project Overview Factsheet (Nov 2016)

View detailed project maps

June 2014 SD PUC Evidentiary Hearing

October 2013 South Dakota Public Input Hearings:

The following materials from the South Dakota Public Utilities Commission Hearing are available for review on the PUC website.

  • Public Hearing Presentation
  • Recording of Public Input Hearing - Aberdeen
  • Recording of Public Input Hearing - Milbank

February 2013 public meetings:

October 2012 public meetings:


©2017 Otter Tail Power Company and Montana-Dakota Utilities Co.