Water use in thermal plants
Some may be surprised to learn that water is needed to make power at thermal generating stations, which are fired by coal, oil, gas or biomass. Here you will find details on why it is 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 heating water, commonly referred to as ‘process water. 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 is used to turn the turbines at our thermal generating stations.
Most of or thermal plans draw cooling water from the ocean. Only the Trenton Generating Station draws water from a freshwater source, the East River. This water is eventually returned to its source at a slightly elevated temperature. Monitoring at our thermal generating stations has shown that a slight temperature increase in the water near the plants does not have significant adverse effects on the fauna and flora in the area.
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, including the use of screens at cooling water intakes to keep fish from entering the plant, or decreasing water speeds to allow fish to escape cooling water intakes.
Each of our thermal generating stations has a waste water treatment system. We collect all water used in our operations, including power plant effluents, coal pile drainage, and storm water runoff from the plant sites and ash landfills. At each site waste water is directed to a waste water treatment facility or lagoon where it is treated until it meets environmental regulations and requirements. Once the waste water has been tested and meets the requirements in our operating approvals, it is discharged into the environment.
Water used by hydro facilities
Water is used to power the turbines that produce electricity at our hydro generating stations. We manage this water through the use of storage reservoirs and 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 power when it is needed, while meeting our environmental management commitments. We regulate water levels in 74 freshwater reservoirs and one tidal estuary.
Operating our hydro facilities is a balancing act. Our first priority is public safety, followed closely by 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. Many Nova Scotians rely on our reservoirs for recreational use, so we try our best to maintain appropriate water levels and flows for their needs.