Water plays a critical role in generating electricity at both our hydro and thermal power plants. More information on our use of water is available in this section.
You might be surprised to learn that water is needed to make power at coal, oil and natural gas-fired generating stations. Here you’ll find details on why it’s needed and how we use it.
The turbines that are used to create electricity at our thermal generating stations are powered by steam. That steam is made from what we call ‘process water’. Process water refers to all freshwater used by the thermal generating stations as part of day-to-day operations. We draw this water either from municipal water systems in the areas where our thermal generating stations are located or, in the case of our Point Aconi Generating Station, from groundwater.
We use ‘cooling water’ to cool down and condense the steam that’s used to turn the turbines at our coal, oil and natural gas-fired generating stations.
Cooling water is drawn from a nearby natural water source such as the ocean or, in the case of Trenton Generating Station, from the East River. This water is eventually returned to its source at a slightly elevated temperature. Monitoring at all thermal generating stations has shown that this slight temperature increase in the water near the plants does not have significant adverse effects.
Other issues associated with cooling water include the potential for fish to be drawn into the cooling water pumps at the intake, the addition of chlorine used to control mussel and bacterial growth in the warmed cooling water and the potential for leaks such as oil to make their way into the water.
We take measures to reduce the potential for these impacts. For example, we use screens at cooling water intakes and/or lower water speeds to help keep fish from entering the plant through the cooling water.
Each of our coal, oil and natural gas-fired generating stations has a wastewater treatment system. We collect all water used in our operations, including power plant effluents, coal pile drainage, and storm water runoff from the plant site and ash landfill. All wastewater is directed to a wastewater treatment facility/lagoon where it is treated until it meets environmental regulations and requirements. Once the wastewater is sampled, tested and has met the requirements in our operating approvals, it is discharged into the environment.
We use water to power the turbines that produce electricity at our hydro generating stations. We manage this water through the use of dams. We run a total of 32 hydro generating stations on 16 watersheds across Nova Scotia. Most of these systems depend on storing water for timed release to let us generate the most power while meeting our environmental management objectives.
In managing our hydro facilities, we regulate water levels in 74 freshwater reservoirs and one tidal estuary across a geographically and topographically diverse area. Most of the 32 hydro generating stations across Nova Scotia have been operating for more than 50 years. Our St. Margaret’s Bay hydro generating station, commissioned in 1922, is the oldest.
Operating our hydro facilities is a balancing act. Our first priority is public safety. Next, we focus on environmental protection. Our water management practices have the potential to affect aquatic species and habitats in rivers and reservoirs. For example, we maintain fish habitat by providing the right flows to protect fish. Of course, generating power is the reason our hydro systems exist, and this, too, is one of our priorities. We are also aware that many Nova Scotians, such as cottage owners, rely on our reservoirs for recreational use, so we try our best to maintain appropriate water levels and flows for their needs.