By Bruce Owen
When the 75-MW Pointe du Bois Generating Station first went into operation in 1911, William Howard Taft was president of the U.S., Norwegian explorer Roald Amundsen was leading the first expedition to the South Pole and the Panama Canal was still two years from opening.
Pointe du Bois is located on the lower reaches of the Winnipeg River after it flows out of the neighboring province of Ontario. It was built by the city of Winnipeg to be the main supply of electricity to the booming prairie city that aimed to be the “Chicago of the North.” When the station went into service, many city residents still cooked on wood-fired stoves and read by kerosene lamp or candlelight in the evening.
But, Winnipeg was rapidly changing. The population had tripled, to 151,958, over the previous decade and more people were arriving daily. Many of the city’s residents, business groups and new industries clamored for affordable electrification.
Pointe du Bois could not come into service soon enough.
|Photo (above): During the 1920s, the original Pointe du Bois spillway was upgraded.|
Much of the electricity this station now produces – on average annually about 599 million kWh – is generated by some of the same 16 horizontal-shaft Francis turbines installed 100 years ago.
When Pointe du Bois first started generating power in 1911, it came from units one to three. As demand grew and equipment and funding became available, more units were added in stages. The additional units were added in 1914, 1917, 1921, 1924 and 1926, bringing the total number of units to 16.
As early as 1915, the Pointe du Bois plant was producing 25,000 continuous horsepower to the city of Winnipeg, but was capable of producing 77,000 hp with the addition of more turbine-generator units.
Pointe du Bois was inducted into the Hydro Hall of Fame in July 2016, at HydroVision International 2016 in Minneapolis, Minn., U.S.
The era of affordable rates
Pointe du Bois was not the first hydroelectric generating station in Manitoba. That distinction belongs to the 14-MW Pinawa Generating Station, commissioned in 1906 and also on the Winnipeg River, built by the Winnipeg Electric Railway Co. The electricity generated was to power the company’s new streetcars, bring to an end the era of horse-drawn public transportation.
Pinawa had extra power to sell to the city, but Winnipeg Electric Railway wanted too much for it – 20 cents per kWh. The mayor and City Hall feared such a steep price would chase away new business and stymie growth (by comparison, today’s residential rate in Manitoba is 7.672 cents per kWh). The city decided to put the issue to a vote and, in a referendum to the electorate, the city asked: Should Winnipeg spend more than C$3 million to build its own hydro-electric plant?
The measure passed by a wide margin – 2,382 votes for and 383 votes against.
|A technician is pictured in this view of the Pointe du Bois control room in 1924.|
Led by city of Winnipeg Alderman John Wesley Cockburn, Winnipeg began developing a publicly-owned utility. Cockburn went so far as to secure the land in his own name for the proposed power plant at what was then known as Pointe du Bois Falls, a set of rapids about 160 km northeast of Winnipeg. When the city created its own utility in 1906, Cockburn transferred the rights, and Pointe du Bois started producing electricity five years later. The per kWh rate for electricity from this station was set at 3.3 cents – a rate that remained unchanged until 1968.
More than 100 years after Pointe du Bois was built, Manitoba’s electricity rates remain among the lowest in North America.
Plant design and construction
As originally designed, Pointe du Bois would have 16 double-horizontal-shaft Francis turbines with a capacity of 75 MW. But before any power could flow, the site and powerhouse had to be developed – no easy job given its remote location from Winnipeg on the bare rock of the Canadian Shield.
Construction began in 1907. The first hurdle was getting men and equipment to a site that at the time was surrounded by thick boreal forest and best accessible only by a canoe or a small boat, which were not the ideal craft to transport workers , construction materials and heavy equipment.
To facilitate this need, Winnipeg’s new utility built a railroad. The task was to run a track from the nearby town of Lac du Bonnet to the site, roughly 60 km away. To do that, they also built two bridges over the Winnipeg River and nearby Lee River.
The next job was building a work camp at Pointe du Bois, which first needed a staff house to provide rooms and meals for workers. But, the community soon evolved to include houses for married staff, a store, a school and even eventually an outdoor swimming pool.
|A current-day view of inside the powerhouse shows several of the original 15 horizontal-shaft Francis turbines, some of which are still in use today.|
The methods of heavy construction at that time, when compared to current methods, relied more on brute force than anything else. This included clearing the land of all trees for the work site by hand, and hewing trees that were usable to use as railway ties or to build cabins for the work camp. Steam powered drills were used, and horses were kept on site to move materials. Work also continued during the grueling winter months when the river froze over.
A dam made of several sections spanned the Winnipeg River. This included a rockfill dam 700-ft long and a concrete section 550-ft in length. Spillway gates – timbers manually lowered and raised – controlled the level of the water in the forebay before the huge powerhouse, also about 550 ft in length. Each generator, in normal conditions, was driven by 4 million tons of water a day.
The plant first produced electricity on Oct. 16, 1911. Gurney Evans, the 8-year-old son of Mayor William Sanford Evans, threw the switch, sending the first electricity generated by the new public utility, City Light and Power (later Winnipeg Hydro), to its first customers in the bustling city.
Manitoba Hydro is currently in the process of upgrading transmission lines from Pointe du Bois to Winnipeg as part of its wider program to modernize the utility’s transmission and distribution network.
At the time, Pointe du Bois could not produce electricity fast enough. Five units went into service in 1911 and 1912. More units were added in 1914, 1917, 1921, 1924 and 1926, bringing the total number of units to 16 and total generating capacity to 70 MW.
The hydro province
Within a few years, Pointe du Bois was followed by five other generating stations on the Winnipeg River as the city and the province grew. Pinawa was decommissioned in 1951 as the full flow of the Winnipeg River had been diverted to the new 75-MW Seven Sisters hydroelectric plant. Located about 90 km northeast of the Winnipeg, Seven Sisters was built by the privately-owned Winnipeg Electric Co. and went into service in 1931.
|Timbers and scaffolding were used during the construction of the powerhouse on the Winnipeg River in 1909.|
The Pointe du Bois powerhouse continues to house 16 turbine-generator units, including 15 double-horizontal-shaft Francis turbines and one GE Canada-made Straflo turbine-generator. The Straflo unit was commissioned on Nov. 2, 1999. One of the original turbines, Unit 1, was decommissioned to accommodate it. The new Straflo unit helped increase the capacity of the generating station to 75 MW. Manitoba Hydro acquired Pointe du Bois as part of its purchase of Winnipeg Hydro in 2002. The provincial Crown Corp. now produces the bulk of electricity on the Nelson River in the province’s north. Manitoba Hydro’s largest plant is Limestone, which has a generating capacity of 1,340 MW.
Compared to modern equipment, the older turbines at Pointe du Bois mirror turbines on display in museums, but the plant still produces power and has paid for itself many times. It was originally built for $3.25 million, a huge amount of money at the time, but relatively inexpensive when compared to cost of a new hydroelectric station today. The same $3.25 million equates to about 1 million in 2016.
The old spillway, installed in 1911 and upgraded in the 1920s and again in the 1950s, was replaced entirely in 2014 at a cost of $560 million. Studies done a decade earlier showed that despite repeated work over the previous decades, the old spillway no longer met modern Canadian Dam Association safety guidelines.
The new spillway and its control gates will do what the old spillway could not, which is maintain the historic flow of the Winnipeg River regardless of the power station’s future and protect about a 2-km-long downstream stretch from the threat of flooding.
|Engineers pose next to the installation of Unit 1 in 1910, the first of 16 horizontal-shaft Francis turbines to be installed at Pointe du Bois.|
Manitoba Hydro has examined replacing Pointe du Bois with a newer, more efficient powerhouse with a capacity of as much as 120 MW, but ultimately decided against it because of the high rehabilitation cost versus the need for new hydro-electric production on the Nelson River (the 695-MW Keeyask Project) and new high-voltage transmission to improve reliability.
The original Pointe du Bois plant requires strict upkeep, but is anticipated to continue producing electricity until 2030, when it will likely be decommissioned.
Bruce Owen is a public affairs officer with Manitoba Hydro.