Frequently Asked Questions

If you don’t find the answer to your question below, please do not hesitate to contact us. We would be happy to provide more information.

Has Emera built a project like this before?

Yes. Emera is currently building a new 500-megawatt HVDC transmission system with a 110-mile subsea portion between the Atlantic Canadian provinces of Newfoundland and Labrador and Nova Scotia. The cables were installed in the ocean this summer. Emera and NB Power partnered about 10 years ago to build Northeast Reliability Interconnect (NRI), an 85-mile overhead AC transmission line connecting the province of New Brunswick and the state of Maine. This transmission line required a Presidential Permit in the United States. The line went into service in late 2007.

Is this a safe way to transmit electricity?

Yes. Similar projects have been developed in many parts of the world, providing experience and effective models to draw upon. Emera is currently completing construction of a new 500-megawatt HVDC transmission system with a 110-mile subsea portion between the Atlantic Canadian provinces of Newfoundland and Labrador and Nova Scotia. The subsea cables for Maritime Link were installed this summer. The project is on budget and on schedule for completion in late 2017.

What are the major parts of this project?

The Atlantic Link project involves installing two HVDC (high-voltage direct current) transmission cables—entering the water near an existing electric substation at Coleson Cove, New Brunswick and coming ashore at a site near the Pilgrim nuclear generating station at Plymouth, MA. The two cables will be installed together in the same corridor. The length of the transmission line, which will be almost entirely underwater, will be approximately 375 miles, depending on the final decision regarding cable routing.

The following elements and associated infrastructure will also be built:

  • two converter stations (at Coleson Cove and at Plymouth) and a new substation in Plymouth
  • onshore anchoring sites
  • other infrastructure, as required

What is HVDC?

HVDC (high-voltage direct current) is an established technology with a long track record of reliable and safe operation around the world. HVDC systems use direct current to transmit electricity rather than alternating current (AC). HVDC electricity transmission systems are less expensive and lose less electricity when used for long-distance power transmission.

Is this an underwater power line?

Yes. Virtually the entire length of the route is under water. As proposed, the subsea cable will be about 35% in Canadian waters and about 65% in United States waters (including Canadian and U.S. exclusive economic zones). Subsea routing makes for a simplified construction process, including fewer splices on the HVDC cable, along with greater reliability and lower cost. The routing of the cable, and its installation, is being planned to minimize impact on marine life and habitat. The largely marine routing proposed for the Atlantic Link reduces impacts on landowners. Emera is committed to consultation with those who have an interest in the area where the cable is to be installed. The marine portion of the line will be laid so that it follows natural protective features such as deep sea valleys and ocean contours. Where necessary, it will be buried approximately six feet under the ocean floor - for example, the line will be covered for protection where the ocean floor is too hard to trench. Rock is generally used for this type of cover, although concrete mattresses specifically designed to protect the cable can also be used.

Does this kind of cable affect marine life?

The routing of the cable, and its installation, is being planned to minimize impact on marine life and habitat. The Atlantic Link is subject to review and approval by environmental regulatory bodies in both Canada and the United States. Route development will include input from those who have an interest in areas where we propose to install the cable. Actual cable installation will be planned so it occurs during periods where we are able to avoid or minimize disruption of normal activities, including fishing/harvesting. Where possible, the cable will be buried with minimal disruption to the seabed. The cable will be buried approximately six feet under the ocean floor. Where the ocean floor does not permit burial, the line will be covered for protection. Rock is generally used for this type of protection, although concrete mattresses specifically designed to protect the cable can also be used. More information is available in our fact sheet, Subsea HVDC cables and the marine environment.

How much power is 1,000 megawatts?

One megawatt (MW) of electricity is enough electricity for around 600 homes on days when demand for power is highest, like a hot summer or cold winter day. The 1,000 MW capacity of the Atlantic Link, if fully utilized, could provide electricity to as many as 600,000 homes on that sort of day.

How will this project benefit New England electricity customers?

This project would provide New England electricity customers with cost-effective access to Canadian hydropower and onshore wind farms (likely built in Atlantic Canada). It would be part of an effort to diversify the energy mix in the Commonwealth of Massachusetts and help reduce greenhouse gas (GHG) emissions, contributing to GHG reduction targets established under the Massachusetts Global Warming Solutions Act (2008). This energy is also needed to replace the energy that will be lost with the scheduled closure in mid-2019 of the Pilgrim Nuclear Station.

What kinds of regulatory requirements are there for this project?

This project will require a number of state, federal and provincial regulatory approvals in both Canada and the United States, including a Presidential Permit from the U.S. Department of Energy and an export permit from Canada’s National Energy Board. There are also local zoning approvals required in the Town of Plymouth.

What about electromagnetic fields (EMFs)?

Electric and magnetic fields (EMFs) are produced by natural forces like the earth’s magnetic field or lightning. EMFs are also generated by electricity and other man-made sources like computers and cell phones. Both electric and magnetic field levels decrease rapidly as you move away from the source.

When electricity flows through a power line, it produces both an electric field and a magnetic field. Direct current (DC) is constant, like current from a battery. Its electric and magnetic fields are also constant and are referred to as static fields. Natural and man-made static fields are all around us. If you've ever walked across a carpet and been shocked when you touched a doorknob, you've experienced a static electric field. Static electric and magnetic fields associated with DC transmission lines aren't generally considered to pose a health concern or to have harmful impacts on marine life.

To find out more about EMFs, visit You'll find HVDC-specific information at The U.S. Bureau of Ocean Energy Management (BOEM) has also issued observations regarding EMFs from submarine cables:

What is Horizontal Direction Drilling and how does it work?

Horizontal directional drilling (HDD) is a steerable underground drilling method to install pipes, casings or cables without having to dig a trench. The Atlantic Link project will use HDD technology at both subsea cable landfall sites in Coleson Cove and Plymouth, creating a protected path through the rock to insert the HVDC subsea cable. Using HDD technology will ensure minimal impact, preventing disturbance to shorelines and sensitive intertidal areas. Emera will conduct baseline sound surveys before HDD work begins, and will monitor sound levels at the start-up of drilling operations to confirm it does not exceed predicted levels.

Where will the project come ashore in Massachusetts?

The Massachusetts landing site will be in Plymouth, near the site of the Pilgrim Nuclear Station which is scheduled to retire in mid-2019. Atlantic Link plans to connect to the high-voltage transmission lines that currently move energy from the Pilgrim plant onto the grid that serves customers in Massachusetts. The company that operates the Pilgrim station, Entergy, has agreed to provide Emera an option for an easement on a portion of its adjacent property. The companies have identified a mutually agreeable parcel that is suitable for Atlantic Link and also meets Entergy’s requirement to ensure safe, ongoing plant operations until shutdown, then planned decommissioning.

What is the project planning to build in Plymouth, and when?

Proposed facilities include a landing site for the HVDC cable, a converter station to change the electricity from direct current (DC) to alternating current (AC), and a new substation to enable connection to the high-voltage transmission line that currently is connected to the Pilgrim plant. The underwater cable will come to shore via an underground conduit created using a process known as horizontal directional drilling, to avoid digging a trench across the beach. The actual physical footprint and height of the facilities depends on final design decisions—which will reflect, among many other considerations, Town of Plymouth zoning requirements and feedback from the community. The new facilities will not take up all of the property for which Emera has an agreement with the owners of the Pilgrim nuclear station.

What arrangement does Emera have with Entergy regarding property near the Pilgrim Nuclear Station in Plymouth?

Entergy has agreed to provide Emera an option for an easement on a portion of its property related to the Pilgrim Nuclear Station (which is scheduled to retire in May 2019). The companies identified a mutually agreeable parcel adjacent to Power House Road which is suitable for landing the submarine cable and connecting it to the electrical grid in Massachusetts. The easement is for a total of 52 acres, although the actual facilities when completed will occupy less than half of that. The parcel under the option agreement not only meets the needs of the Atlantic Link project - but also Entergy’s requirement to ensure safe, ongoing plant operations until shutdown, then planned decommissioning.

How close will the proposed Plymouth converter station be to local residents?

The converter station will be more than 1,000 feet from the nearest residence. There will be a temporary pad to enable horizontal direction drilling to create a conduit for bringing the Atlantic Links on to shore. This drill pad will be about 500 feet from the nearest residence.

Will the converter station in Plymouth have floodlights around it?

Emera is mindful of light pollution and will design lighting for the facilities that is consistent with community expectations.

Will payments that the Town of Plymouth receives go up every year?

Emera has proposed paying the Town of Plymouth a consistent annual PILOT (Payment In Lieu Of Taxes) amount for the entire life of the contract awarded under the Massachusetts Clean Energy RFP process, rather than an annual payment that is consistent with the depreciated value of the facilities. The proposed PILOT payment is $2.5 million per year. 

What effect will the new facility in Plymouth have regarding views from the ridge of Pine Hills toward Provincetown?

Emera believes the final chosen location for the converter station, as well as facility design, will accommodate community expectations regarding view planes, and is committed to constructive dialogue with stakeholders on this issue.

How loud will the converter stations be and what will I notice?

Sound produced by the operation of equipment in the converter station can be managed through proper design of a building to enclose the converter station, and maintaining vegetation (i.e. trees) around the facility. A sound study is being conducted so there is baseline information about sound levels prior to any construction of Atlantic Link facilities. A report produced for a hearing before the independent electric system regulator in the Canadian province of Manitoba in 2014 indicated that measureable sound about 1,000 feet away from a converter station without sound mitigation design measures should be under 60 decibels (dB). In Plymouth, mitigation/attenuation measures (such as building design, vegetation) would ensure measureable sound from Atlantic Link facilities are at levels acceptable to the community. The World Health Organization’s recommended guideline is 40 dB outdoors at night. 40 dB is equivalent to "a library, bird calls, lowest limit of urban ambient sound”; 30 dB is a "quiet rural area".

Can the converter station in Plymouth be enclosed in a building or somehow shielded from view?

It can. Emera plans to use buildings, terrain design and vegetation to help the facility be as unobtrusive as possible.

Can the Plymouth converter station be built in a different location?

The converter station is ideally located as close as possible to the existing high-voltage transmission line that connects the grid to the Pilgrim Nuclear Station. In order to bring the HVDC cable ashore without a trench that crosses a beach area, a conduit will be drilled underground using horizontal directional drilling. In order to enter the conduit in deeper water, the cable must have an on-shore landing point as close as possible to the water. The agreement with Entergy is consistent with having the converter station and substation as close as possible to both the ocean where the cable comes ashore, as well as the existing high-voltage transmission line.

Can Emera delay its plans in Plymouth until the completion of a process to review future use of all of the property Entergy owns around the nuclear plant?

The Massachusetts Clean Energy RFP, to which Emera has responded, required that proposals be submitted by July 27, 2017. The Atlantic Link proposal can be found here.  Emera has received general support from the Plymouth Board of Selectmen regarding its proposal, but is committed to work with the community to ensure Atlantic Link facilities are built in a manner than respects local policy and community direction for property that includes the parcel under agreement between Emera and Entergy.

Why would Emera not just put these facilities on the current Pilgrim plant site?

The current Pilgrim Nuclear Station site was considered but it is not available to the Atlantic Link project because of planned decommissioning activities.

How long will these facilities be in service? Will they need to be taken down after the 20-year term of the contract that is awarded under the Massachusetts Clean Energy RFP process? Who would pay for that?

Well-maintained converter and substation facilities have an expected operational life of 40 years or more; and can be updated or replaced as required. Today’s HVDC cables have a similar expected operating life. It will be Emera’s responsibility to redevelop the facilities to extend their life, or to remove the facilities and remediate the site.

After the cable is buried on the ocean floor, will it affect marine life?

2016 study conducted after installation of Basslink, a 180-mile submarine HVDC cable between Australia and Tasmania, found “transient and minor” ecological effects in the marine environment. It also found that even when the cable was on the ocean floor without protective covering, magnetic and electric fields did not prevent local sea life from using the cable for habitat, much as they would the surrounding reef. That study concluded: “The findings should allay some of the community concerns concerning the environmental effects of installation and operation of HVDC monopole cables with metallic return”.

How long will it take, after burial on the ocean floor is completed, for things to return to normal?

That depends on the specific marine environment where the submarine cable is buried. Atlantic Link will be buried for most of its length and, where not buried, covered by rocks or specialized concrete mattressing. A 2001 study regarding the SwePol HVDC cable between Sweden and Poland found that one year after construction, there were no visible changes to the sea bottom and no obvious changes in the “composition, abundance or biomass” of marine life that could be related to disturbance caused by cable construction.

How will cable installation affect right whales that live in Cape Cod Bay, and migrate up the coast to the Bay of Fundy?

Surveys to finalize the cable route, expected in 2018, and actual cable installation, likely in 2021 and 2022, will be structured to minimize potential conflict with marine mammals, including right whales. The time required to conduct the survey and installation is relatively short (a matter of days in any specific area) and the vessels do not move quickly. Use of technology and experienced marine mammal spotters on vessels used for the survey work and cable installation is planned.

If Emera wins the RFP, what happens after the 20-year contract is over?

Emera expects that new commercial arrangements will be made that would see continued use of the facilities constructed in Plymouth and in Coleson Cove.

Will there be community meetings on the project?

Emera is committed to ongoing consultation with stakeholders and the public. A public meeting was held at the Manomet Youth Center in July 2017, and a public consultation meeting and site tour was held on October 18, 2017 as part of an assessment of the scope for environmental review by the Massachusetts Environmental Policy Act (MEPA) Office. We believe it is important to maintain and develop relationships with landowners, residents and elected officials along the Atlantic Link route. Please contact us if you would like to meet.

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