The electricity grid is something residents and businesses rely on every day to turn on lights and computers, to cook, or maybe even drive to work. It is an often-underappreciated asset in our energy sector, despite being right in front of our eyes.

How does the electrical grid work?

Electricity is generated by a source like hydropower, wind, solar, nuclear, and fossil fuels, among others. The electrons flow in a current though the electrical grid, which carries them to consumers in a series of power lines and substations.

To travel longer distances, electricity is carried via transmission lines at a high voltage, kind of like a highway. These lines are typically thicker and higher off the ground. A substation is used to increase the voltage for transmission, and once it reaches its destination, another substation is used to decrease the voltage so it can be used more easily in homes and businesses. Substations can be likened to an interchange on a highway to allow you to exit to a town or city along the highway route. Distribution lines are the wires strung on shorter (often wood) poles which carry electricity customers. You could say these are like the streets in your town or neighbourhood.

Electricity generation is important to have available when consumers need it, so there is a lot of work that goes into controlling when and where the power is created, and how it gets to where it is needed. Electricity generation is often spread widely across a province and is located relatively close to large populations to help improve its reliability and security (visit Atlantica’s Energy Maps to learn more).

Utilities must constantly ensure the grid’s supply of electricity meets demand to maintain reliable services. In the Maritimes and in Northern Maine, the Office of the Transmission and System Operator is responsible for meeting this balance.

Substation diagram

Source: U.S. Department of Labour, Occupational Safety and Health Administration, Electric Power Generation, Transmission, and Distribution eTool

What is the difference between dispatchable and non-dispatchable generation?

Electricity generation can be either dispatchable or non-dispatchable. Dispatchable means a generation source is available on demand – the power can be switched off or on as needed. Examples of dispatchable generation include natural gas and other fossil fuel-burning facilities, biomass and often hydro.

Non-dispatchable sources produce electricity when the generation source is available, such as solar and wind. These renewable sources are considered variable, and this is where battery technology can help store energy from renewables and other sources to help it be more dispatchable. Traditional nuclear generation produces consistent energy as opposed to variable, but the current large scale CANDU nuclear technology on the grid is not quick to turn on or off.

Typically, consistent sources like nuclear and dispatchable sources like fossil fuels are used as baseload electricity generation to meet the everyday needs of consumers. Having access to baseload generation is critical for grids in Canada where demand fluctuates dramatically by time of day and by season. As days become colder, more energy is needed to heat homes and businesses. Similarly, heating water needed for showers or washing laundry and dishes means more electricity is needed in the mornings and evenings. Grids must integrate non-emitting sources of generation to reduce emissions but must also ensure residents and businesses have enough electricity to meet demand.

What is the role of the grid in Atlantic Canada’s net-zero future?

To reach net zero targets, many Atlantica Canadians and local businesses will need to rely on more electricity and clean fuels. Our electrical grid will play an incredibly important role helping ensure access remains to clean and reliable energy, at an affordable price.

So what do electricity utilities and governments need to accomplish to make this possible?

Steps include:

  • maintain existing non-emitting generation infrastructure;
  • replace coal-fired electricity generation and limit use of other fossil fuel-fired generation;
  • develop new non-emitting generation and transmission to help meet increasing demand;
  • modernize and improve existing grid infrastructure and processes; and,
  • help limit electricity demand growth and peaks with demand side management and improved efficiency.


Full disclosure: The Atlantica Centre for Energy represents many of the largest energy producers and consumers in Atlantic Canada, including renewable energy. However, the Centre’s members also represent governments, research groups and academia. The Centre examines all types of energy to help decarbonize while growing economies across the region.