How BC Hydro powers B.C., and what we're working on
A complex system needed to deliver electricity from our facilities to your home
Posted by Tanya Fish
Our electrical system is vast and complex. It features 31 generating stations, three thermal generating plants, and over 76,000 kilometres of transmission lines that traverse some of the most challenging terrain in the world. We supply power to 95 per cent of the province — and we have about 1.9 million customers.
Turning water into electricity
The BC Hydro system generates over 43,000 gigawatt hours of electricity a year, more than 90 per cent of it through hydroelectric generation. Here's how water in B.C.'s rivers turns into the electricity that lights your home:
- It starts at a hydroelectric dam, which stores water in a reservoir. When the water is released from the reservoir, it travels through the dam and is converted into kinetic energy — energy produced by motion — by flowing through a an enclosed pipe known as a penstock that funnels water to turbines
- The flowing water then turns a turbine, which is connected to a generator. As the turbine turns, the generator converts that kinetic energy into electric energy.
- A step-up transformer then increases the voltage of the electric energy produced by the generator so that transmission lines can carry it efficiently over long distances.
Peace and Columbia rivers power a province
Our Peace (Northern) and Columbia systems are responsible for the majority of BC Hydro's electricity generation. These two systems harness the power of B.C.'s two largest rivers — the Peace and Columbia.
The G.M. Shrum Generating and the associated W.A.C. Bennett dam — located along the Peace River near Hudson's Hope — supplies over 23 per cent of the power for the province and is the cornerstone of our entire system. Completed in 1967, it's one of the world's largest earth filled structures, stretching two kilometres across the head of the canyon and measuring 183 metres in height.
In the Columbia region, the Revelstoke and Mica Generating Stations are our two largest facilities with a generating capacity of 2,480 megawatts and 1,805 megawatts respectively. Hydroelectric development in the Columbia region was greatly influenced by the signing of the Columbia River Treaty.
Transmission and distribution
The southwest region of B.C. is the most densely populated area of the province, but our major generating stations are located hundreds of kilometres away, in the North and Columbia regions. We depend on our extensive transmission and distribution system to ensure the power gets to where it's needed.
The electricity generated at our large generating facilities gets to the Lower Mainland and other areas of the province via high-voltage lines strung between the big steel towers of our transmission network. From there, the high-voltage electricity flows through our substations and distribution transformers to step the electricity down to a safe and usable voltage level. Our distribution system — consisting of over 55,254 kilometres of distribution lines, enough to circle the earth twice — then carries the electricity to customers' homes and businesses.
Meeting increased demand in the winter season
Colder temperatures and fewer daylight hours increase electricity use across the province in winter. We're fortunate to have the flexibility in our system to allow us to manage the availability of generation during times of higher use. This can be done almost instantaneously by increasing or decreasing the flow of water through the dam.
More turbines, a new dam, will help meet future demand
To keep up with B.C.'s growing electricity demand, which is expected to grow 40 per cent over the next 20 years, we're investing in our system to ensure we can continue to meet the province's electricity needs.
One project that will increase the capacity of our system is the installation of two new generating units at Mica Generating Station, located north of Revelstoke. Mica was originally designed to hold six generating units, but only four were installed when the station was constructed in the 1970s.The two new generating units will provide an additional 1,000 megawatts of capacity to the system.
The recently approved Site C Clean Energy Project (Site C) will be the third dam and hydroelectric generating station on the Peace River in northeast B.C. Expected to be completed and in service by 2024 , Site C will provide 1,100 megawatts (MW) of capacity, and produce about 5,100 gigawatt hours (GWh) of electricity each year — enough energy to power the equivalent of about 450,000 homes per year in B.C.
Construction is scheduled to begin in summer 2015.