Transporting electricity

Because power plants, especially hydro stations, have often been built in remote locations, transmission lines often travel over long distances. There are more than 160,000 kilometres of transmission lines in Canada.

Power lines can affect land through the siting of facilities and rights-of-way, vegetation management and the disposal of waste materials. There is also public concern over potential health effects of electric and magnetic fields from power lines and electricity facilities.

Siting of facilities

Transmission lines travel along corridors through urban, rural and wilderness areas. In wilderness areas such as forests and wetlands, the construction of clearcut transmission corridors disturbs land and increases human access, affecting wildlife and their habitat.

Before building new transmission lines, power companies must get provincial and local permits, covering land use and environmental issues. Companies carry out environmental impact assessments on route alternatives and work with regulators and interested parties to identify the most direct and acceptable routes.

In residential areas, it is a common practice to place low voltage distribution lines underground.

Vegetation management

Power companies use a variety of methods such as mowing, hand cutting, trimming and herbicides to carry out vegetation management to keep trees from growing until they contact power lines and cause hazards and service interruptions. Utilities are involved in ongoing research to better understand the effects of right-of-way management practices. Research has led to more effective use of herbicides, which also reduces costs and environmental impacts.

PCBs

PCBs are synthetic liquid chemical compounds consisting of chlorine, carbon and hydrogen. Their fire-resistant and insulating properties make them suited for use as cooling and insulating fluids.

Up until the 1970s, many pieces of electrical equipment, including transformers, used polychlorinated biphenyls (PCBs) in cooling and insulating oil. Because of PCB-related health concerns, the Canadian Environmental Protection Act (CEPA) has banned PCB production and set out strict guidelines for use and storage of PCB-containing equipment.

Power companies work closely with governments and regulators to reduce the storage and use of PCBs and to prevent their release into the environment. Since the late 1980s, the electricity industry has followed voluntary guidelines to gradually phase out PCBs from equipment and send materials for disposal at licensed facilities. Guided by environmental management plans, Canada’s electric utilities are working toward the goal of PCB-free operations, steadily replacing PCB-containing equipment and oil with non-PCB materials. Today nearly all equipment containing high levels of PCBs — over 500 parts per million (ppm) has been removed from service. According to the Canadian Electricity Association, the industry’s inventory of high-level PCB-containing equipment in storage dropped from 3,813 tonnes in 1997 to 104 tonnes in 2001.

The industry also continues to reduce the amount of lower level PCBs in equipment. Over 1997 to 2001, the inventory of low-level material in storage declined from 2,611 tonnes to 849 tonnes.

Some utilities now report having no PCBs in storage while others report have completely eliminated PCBs from their transmission and distribution systems.