Electric and magnetic fields

Will the cables produce electromagnetic fields?

Update on the impact of the underwater cable project’s electromagnetic field (EMF)

First, it’s important to remember that EMFs are everywhere. There is a natural electric field on the Earth’s surface that is created by electric charges in the upper atmosphere. The Earth is also surrounded by a magnetic field that can be detected with a compass. It is generated by electrical currents produced by the motion of the molten matter in the Earth’s core.

An electric field is generated by the presence of electrons and measured in volts per metre (V/m). The higher the voltage supplied to an appliance, the stronger the resulting electric field. The strength of an electric field can be substantially reduced by anything that acts as a screen, such as trees, fences and buildings.

A magnetic field is generated by the movement of electrons and measured in microteslas (μT). The higher the voltage supplied to a cable, the stronger the resulting magnetic field. Unlike electric fields, magnetic fields are not reduced by trees, fences or buildings; the field passes easily through such barriers.

An induced electric field can be produced by sea currents, or by a fish crossing a natural magnetic field or one produced by cables.

Gaspé lobsters are normally exposed to a magnetic field of about 53.31 μT

Whereas Îles-de-la-Madeleine lobsters are accustomed to a magnetic field of 52.47 μT.

Important fact

In the Gulf of St. Lawrence, the Earth’s magnetic field averages 52.83 μT. The Earth’s magnetic field varies from place to place and according to the day and time. This is what will be called “natural variation” below.

Electric field

The metallic armoring around the line will confine the electric field.

Coupe schématique d'un câble sous-marin

Magnetic field

The magnetic field generated by the cables will be weak and will decrease very rapidly the greater the distance to the cables, as shown in the figure below.

Magnetic field generated by underwater cables (1.2)

A few metres from the cables, the magnetic field will be of the same order of magnitude as the natural variation of the Earth’s magnetic field, or about 0.1 μT.

Induced electric field

An electric field induced by marine currents crossing the cables’ magnetic field only impacts their immediate vicinity.

Finding 1

The magnetic field will decrease very rapidly the greater the distance to the cables.

Finding 2

A few metres from each side of the cables, the magnetic field will be of the same order of magnitude as the natural variation of the Earth’s magnetic field.

Finding 3

A few metres from each side of the cables, the induced electric field related to the cables’ magnetic field will be equal to natural ambient conditions.

1 All analyses and figures are based on an annual average supply of 125 amperes.

2 The magnetic field generated by the cables is represented without the contribution of the Earth’s magnetic field.

A few metres away from the cables, the electromagnetic field they generate is the same as the natural variation. Here is how this field is felt by some species:

Rays, sharks and other cartilaginous fish

  • Local perception of cables.
  • Slight behavioral changes, depending on the species.

Crabs, lobsters, salmon and other species that sense magnetic fields

  • Perception of cables a few metres away.
  • Slight behavioral changes, depending on the species.

Important fact

No study conducted anywhere in the world has demonstrated that such behavioral changes have a significant ecological impact on migration or reproduction of marine species, for example.

I’m already used to a magnetic field variance of about 0.1 μT per day. A few metres from the cables, it will make little difference to me.

I was told that the cables would be buried 1 metre deep in the seabed in most places, and even at 5 metres near the coast. I don’t think we’ll be crossing them often!

1

The underwater line will not generate an electric field outside the cables.

2

The magnetic field and the induced electric field will be weak and will decrease very quickly upon moving away from the cables. A few metres from the cables, the magnetic field will be of the same order of magnitude as the natural variation of the Earth’s magnetic field.

3

No studies have shown that the cables will cause behavioral changes with significant ecological impacts on marine specie migration or reproduction, for example.

Lobsters are reassured by the fact that the magnetic field generated by the underwater line will be of the same order of magnitude as the natural variation of the Earth’s magnetic field.

Justification, cost and reliability

Why did you choose to supply electricity to Îles-de-la-Madeleine using subsea cables from Gaspésie?

Hydro-Québec has undertaken to gradually convert its off-grid systems to cleaner, less costly energy sources.

For Îles-de-la-Madeleine, the solution selected is to link the archipelago to Gaspésie by means of subsea cables in conjunction with establishing a microgrid. The thermal power plant will be kept as a backup facility in order to ensure reliable service. This solution offers many advantages:

  • 94% reduction in GHG emissions from power generation in Îles-de-la-Madeleine
  • Green energy as a lever for economic development and transportation electrification initiatives
  • Fewer environmental risks associated with the use of petroleum products
  • Technology showcase for microgrids

What does connecting the islands by subsea cables entail?

Starting in 2025, the islands will be supplied with Hydro-Québec’s clean, renewable energy via underground and subsea cables from Gaspésie.

Hydro-Québec plans to install a link consisting of two subsea cables extending nearly 220 km between Cap-aux-Meules substation and Percé substation, in Val-d’Espoir. The cables will have an 80-MW capacity and be laid together in the same trench.

The project also calls for the addition of a converter at either end of the cables: one at Percé substation, to convert the alternating current into direct current, and another at Cap-aux-Meules substation, to convert the direct current back into alternating current. This conversion is necessary because direct current is better suited to long-distance transmission than alternating current.

We will try to adjust the work period and our installation methods to minimize their impact. However, at this stage of the project, it is too early to determine schedules and work methods.

What will the Îles-de-la-Madeleine connection project cost?

The project’s cost will be confirmed in the coming months as work advances on the technical and environmental studies for the draft design phase.

The cost of supplying electricity is expected to drop by 20% to 25% over 40 years, compared to today’s costs with the thermal power plant.

Are the cables reliable?

The technology used for the subsea cables has been proven for many years.

According to statistics, most subsea cable damage is caused by collisions with fishing gear or boat anchors when the cables are not adequately protected. Hydro-Québec carries out all the necessary studies required to properly document the risks associated with fishing and anchors with a view to adjusting cable protection systems accordingly (as required, by burying, riprap, cast iron shells or concrete mattresses) to minimize these risks.

Are there any plans to connect Île-d’Entrée?

This is not part of the plans for the current project. According to Hydro-Québec’s Strategic Plan, a call for proposals for connecting Île-d’Entrée should be issued in 2020.

What will the microgrid project involve?

The microgrid project involves using innovative technologies for the complementary generation of intermittent energy, energy storage and energy management. It aims to make the Îles-de-la-Madeleine a technological showcase for the integration of renewable energy sources. Transportation, which accounts for 45% of the islands’ greenhouse gas emissions, is also a key concern for Hydro-Québec.

Watch the video to learn how a microgrid works.

A microgrid is a community-centered initiative designed to meet local users’ needs. The project is currently being defined in cooperation with the Communauté maritime des Îles-de-la-Madeleine and will address residents’ needs. It will be presented officially in 2019, and integration will be carried out gradually.

What is the status of the 6-MW wind turbine project?

Hydro-Québec has agreed to purchase the power generated by the Valeco wind farm and its partners (the Régie intermunicipale de l’énergie Gaspésie–Îles-de-la-Madeleine and Plan A). The wind farm should be in service by the end of 2019, in the Dune-du-Nord sector. It offers the following benefits:

  • Reduce greenhouse gas emissions from the Cap-aux-Meules thermal plant by approximately 13% a year, or some 17,000 t CO2 eq.
  • Generate economic spinoffs at the local and regional levels thanks to the partnership with the Régie intermunicipale de l’énergie Gaspésie–Îles-de-la-Madeleine.
  • Bring down heavy oil supply costs for the Cap-aux-Meules thermal plant.
  • Îles-de-la-Madeleine will have the first wind/diesel hybrid (WDH) system, making it a major source of new knowledge for Hydro-Québec.

Power plant and jobs

What will happen to the current power plant and the jobs there?

The current power plant will be maintained as a backup facility to ensure reliable service and support Hydro-Québec’s commitment to preserving jobs in the islands.

Hydro-Québec intends to maintain long-term operations in Îles-de-la-Madeleine to preserve jobs.

For how long will the power plant continue to be operational?

The Îles-de-la-Madeleine thermal plant, opened in 1991, is equipped with six motors of 11,000 kW each. On average, those motors have run for more than 101,000 hours since the plant was commissioned.

The energy transition will significantly reduce use of the power plant’s motors. As a result, the plant’s long-term viability is not an issue.

  • According to a conservative assumption supported by a comparative analysis of identical motors in Madeira, Portugal, these motors are able to operate for 180,000 hours.
  • Our specialized teams carry out exemplary maintenance on all plant components on an ongoing basis, including replacing obsolete equipment.

Surveys and natural environment

What are geophysical surveys and when will they be carried out?

Geophysical surveys are planned for 2019. The seabed will be studied and mapped to determine its bathymetry, currents and surface sediments (in the top five metres) and to image the seabed, in particular to identify obstacles. The surveys will enable us to identify a route for the cables, determine our installation methods and calculate project costs.

The team will comprise engineers, oceanographers and Hydro-Québec employees, including two experienced biologists or recognized observers who will monitor cetacean activity to avoid collisions and minimize disturbances. These observers will also watch for fishermen’s buoys to avoid fishing gear. In the event of any contact with fishing equipment, the location will be noted to facilitate follow-up with the fishermen in question.

Fishing

Will the subsea cables have any impact on fishing or the seabed?

The studies in progress will give us a better understanding of the marine environment so that we can select the cable route that has the least impact while remaining technically and financially feasible.

The impact of cable installation will be very limited, in both time and space. The choice of route, installation methods, means of communication with fishermen and land users, work period and mitigation measures will keep the impact to a minimum.

At this time, our goal is to gain a better understanding of fishing activity in the area in order to adjust the project as required and thereby reduce the impact on fishing. If you are a fisherman active in the marine zone under study, you are invited to speak with the project team, who will answer your questions and gather your input. The information you share will remain confidential and be used solely to develop this project and minimize its impact on fishing and the marine environment.

How can we prevent the cables from getting caught in anchors?

The cables will be buried or protected (covered in riprap, cast iron shells or concrete mattresses) and marked on nautical charts. Hydro-Québec conducts all the studies necessary to document risks associated with fishing and anchors with a view to adjusting cable protection systems accordingly (as required, by burying, riprap, cast iron shells or concrete mattresses) to minimize these risks.

We will take factors such as navigation areas into account to determine the route with the least impact. The possibility of emergency anchoring will be included in the requirements for cable design and protection.

To that end, the project team is gathering information on fishing activity in the study area in order to adjust the project as required and thereby reduce the impact on fishing. If you are a fisherman active in the marine zone under study, you are invited to speak with the project team, who will answer your questions and collect your input. The information you share will remain confidential and be used solely to develop this project and minimize its impact on fishing and the marine environment.

Work

What’s the work schedule like?

It’s still too early to determine the work schedule conclusively, but we estimate the land-based construction work (substation and underground lines) will take place intermittently over a two-year period (2023–2024). The marine-based construction work should take three to four months (2025).

Will the work have any impact on tourism?

Hydro-Québec understands the importance of tourism for the community.

The work area will be very limited, and Hydro-Québec aims to adjust the work period and methods to minimize their impact. However, at this stage of the project, it is too early to determine schedules and work methods.

Discussions and collaboration with the community

When and how will you consult the community?

The project team met with representatives from municipalities, local organizations and various provincial departments in November 2017 and June 2018. Open houses held in Îles-de-la-Madeleine and Gaspésie in June 2018 gave the public opportunities to ask questions and talk with the project team.

Meetings with fishermen, Indigenous communities and the public are ongoing and will continue so that Hydro-Québec can share information about the project and hear any concerns. Information on upcoming meetings.

Hydro-Québec is committed to working with the community on the Îles-de-la-Madeleine energy transition project. The project team has agreed to keep channels of communication with residents open every step of the way.

These exchanges are invaluable. They increase our knowledge of the community and territory and give us a better understanding of residents’ needs and concerns. This makes it easier to work together to develop the most effective solutions.