Long before hydro power began providing electricity, it was used to perform simple but labor-intensive tasks.
Hydro power historically has been one of Alberta’s oldest and most important sources of energy. For over two thousand years, humans have developed ways to harness the energy of moving water. The specific forms of hydro power have evolved tremendously over the centuries, from simple water wheels used to operate small mills to vast hydroelectric dams that help power cites. Regardless of scale, the basic principle behind hydro power has remained the same: the kinetic energy of water is converted into mechanical energy and used to generate power or, with turbines, electricity.
Hydroelectricity is a clean, renewable energy and has remained an important source of power in many parts of the world, including Canada. In 2013, for example, Canada ranked third behind only China and Brazil in hydroelectricity production. The fuel, flowing water, is free and self-renewing, and can be stored in reservoirs until needed. Hydroelectricity produces no pollution, though the damming of rivers can have a dramatic and adverse impact on surrounding ecosystems. This negative impact can be mediated somewhat by run-of-the-river projects, which harness the energy of rivers without creating large storage reservoirs and flooding the surrounding area. Such projects tend to be much smaller than conventional hydro dams, however, and produce considerably less power. They are also subject to fluctuations in precipitation, since they cannot store water to compensate for periods of limited rainfall.
Hydro power has historically been one of Alberta’s most important sources of energy. Some of the province’s earliest power-generating stations were hydroelectric, and up until the 1950s, the majority of Alberta’s power came from rivers. Hydroelectricity evolved in the early twentieth century to meet the enormous power demands of a dynamic, rapidly growing province. In many ways, the history of hydro power reflects many of the broader themes in the history of modern Alberta and comprises an essential part of the province’s energy and resource history.
Hydro Power in Ancient Times (ca. 300 BCE–500 CE)
Long before hydro power began providing electricity, it was used to perform simple but labour-intensive tasks. There is no consensus among historians regarding when and where the earliest hydraulic technology emerged. It is clear, however, that water power was used extensively in the Roman Empire and eastern Mediterranean region by at least the first century BCE. At this time, water-powered technology took the form of waterwheels—bladed wheels that sat on either a horizontal or vertical axis and transferred the kinetic energy of moving water into mechanical energy, most often to turn a millstone to grind grain into flour. The simplest in design was the horizontal waterwheel, which was usually positioned directly underneath the floor of a mill. The wheel sat horizontally in flowing water and was connected to the millstone by a simple vertical axle that turned as the water pushed the blades of the wheel; the turning wheel would thus rotate the millstone.
The simplicity of its design made the horizontal waterwheel relatively inexpensive and easy to operate. However, it provided much less power than the more common vertical waterwheels, which sat upright and transferred the kinetic energy of the water into mechanical energy through a series of gears and wheel-shafts. The first type of vertical waterwheel was the undershot model, which stood upright with the bottom portion submerged in the river or stream. The natural flow of the water would provide the energy necessary to turn the blades, much like a horizontal waterwheel. The undershot wheel, however, was much more efficient at transferring the kinetic energy of the water into mechanical energy. The primary disadvantage of the undershot wheel was that it depended on the steady, consistent flow of the river or stream. If water levels were too low, there would not be sufficient energy to turn the wheel; conversely, too much water would submerge the wheel and render it useless.
These problems were largely solved by the second variant of vertical waterwheel, the overshot wheel. Construction of an overshot waterwheel typically involved the diversion of water from a river through an aqueduct, thus allowing the operator more control over regulating the flow of the water. The water was delivered to the wheel through a flume, and the wheel was turned at once by the flow and weight of the falling water. Overshot wheels were more expensive to build because they required water to be diverted from a stream or river; however, because they gained the additional advantage of gravity (the weight of the falling water), overshot wheels were much more powerful than undershot or horizontal models.
Hydro Power in the Middle Ages (ca. 500 CE–1500 CE)
Between 500 and 1500 CE, the use of hydro power exploded across much of Europe and Asia. The foundational waterwheel designs (horizontal, undershot, overshot) remained the same, but were modified, refined, and at times adapted for new environments. Written records for the Middle Ages are often fragmentary and incomplete, so it is difficult to fully detail the spread and extent of water power usage in this period. The records that do exist, however, paint an impressive picture. One of the most comprehensive sources available for the study of this period is the Domesday Book, an extremely thorough survey of land use and ownership launched by the Crown of England in the late eleventh century. The Domesday Book indicates that there were over 5,600 watermills in England in the 1080s, situated in over 3,000 different locations. Southern France and northern Italy were also regions where hydro power was used extensively. The Bazacle, a dam and mill complex on the River Garonne in southern France, was likely the largest dam in Europe (and possibly the world) at the time it was built.
Other evidence points to the growing importance of tide mills in this period—mills built along coastal areas, powered by undershot waterwheels that drew their energy from the rising and falling of the tides rather than from the steady flow of rivers. Archaeological excavations indicate that such mills were built along coastal Ireland as early as the seventh century, and became increasingly common on the shores of the British Isles and France over the next several hundred years. The use of hydro technology in the Middle Ages was not confined to Europe; indeed, the available evidence points to a flourishing of water-powered technology in other parts of the world as well. Dozens of archaeological sites, most particularly in present-day Iraq, Iran and the Arabian Peninsula, point to the extensive use of water power throughout the Islamic world after the seventh century. Similarly, the use of water power grew in China in this period. By the late tenth century, the Chinese government owned and operated water mills to ensure the supply of flour to the imperial capital.
Hydro Power from the Early Modern to the Industrial Age (ca. 1500–1850)
In the early modern period, water power continued to be used throughout the world for traditional purposes like milling grain and lifting water. By the late eighteenth century, however, water power was playing a crucial role in the early stages of industrialization. The Industrial Revolution is most often associated with the application of steam power to transportation and production, resulting in the rise of railways, steamships and factories. In fact, it was water, not steam, power that was the driving force behind the earliest stages of industrialization in Britain. Water-powered reciprocating devices operated trip hammers and blast furnace bellows in the iron industry—crucial to early industrialization. Waterwheels built in this period were often larger than their predecessors and constructed with iron rather than wood, generating more power and allowing for higher production.
It was in the textile industry that the industrial application of water power was most fully realized in eighteenth-century Britain. In 1769, Richard Arkwright invented the “water frame,” a water-powered machine that spun cotton into yarn—a laborious, time-consuming process when done by hand. The water frame dramatically increased the efficiency of cotton spinning and set the stage for the production of textiles on an unprecedented scale. What was once undertaken on an individual basis at home was now accomplished by workers concentrated in a factory setting, invariably near a source of water power. The first cotton mill in Britain was established in 1771 in Derbyshire, and for the next two decades, Britain would have a virtual monopoly on water-powered spinning technology. Indeed, the water frame and other inventions were deemed so central to the national interest that the British government passed laws restricting the export of machinery and the emigration of people with intimate knowledge of industrial technology!
Modern Hydroelectric Power (1850 to Present)
Water power had played a crucially important role in the early stages of industrialization in Britain and America. It provided a cheap, reliable source of energy that powered the earliest factories and ushered in the era of mass production. Yet, hydro power brought with it two major disadvantages. First, it required a relatively mild climate in order to be fully effective—frozen rivers produced no power, while rivers swollen with excessive precipitation flooded and destroyed mills. Second, the location of hydro mills was by necessity limited to rivers—this proved very restrictive, especially in the industrial age when many other considerations (such as labour and fuel supply, proximity to markets and transportation) became crucially important. Watermills, so crucial a supplement to human and animal labour for over two thousand years, thus fell into disuse by the mid- to late-nineteenth century, replaced throughout the industrialized world with steam power. This process, however, did not bring an end to the importance of hydro power in human history. The age of watermills may have passed, but the age of hydroelectric power was about to begin.
The hydraulic turbines that produce power at modern hydroelectric dams operate on the same principles that powered waterwheels of times past. The water behind the dam flows through an intake and pushes against blades in a turbine, causing them to turn. The turbine spins a generator to produce electricity. The amount of electricity that is generated depends on how far the water drops and how much water moves through the system. Some rivers have either a steep enough grade or a sufficient water flow to generate electricity as the water passes directly through the dam. Hydroelectric dams of this type are called “run of the river” dams. Other hydroelectric dams require the creation of an artificial headpond or reservoir that raises the water level on one side of the dam by holding back large volumes of water. The electricity, once generated, can be transported over long-distance electric lines to homes, factories, and businesses.
Early Alberta Hydro History to 1913
The early development of hydroelectric power in Alberta was a direct product of the province’s great immigration and settlement boom of the early twentieth century. As in the rest of North America, it was the explosive population growth in urban centres that drove the demand for electricity in Alberta. Between 1901 and 1911, Calgary’s population increased nearly tenfold, from 4,398 to 43,706. It was this tremendous population growth, coupled with the city’s close proximity to the powerful water resources of the Rocky Mountains, that made Calgary the epicentre of Alberta’s early hydroelectric development.
Calgary’s first hydro plant was nothing like the enormous mega projects that would characterize hydro later in the twentieth century. It was a small shack-like building constructed by the Calgary Water Power Company in 1893. This two-storey structure was built along a weir spanning the south bank of the Bow River and Prince’s Island, just north of downtown Calgary. This barrier altered the flow of the river and pooled water so that it could be channelled through the plant. It was originally built to supplement the company’s wood-fueled steam plant, but was later connected to a generator that provided electricity to much of Calgary. In 1894, the Calgary Water Power Company was granted a ten-year monopoly on providing Calgary with electricity.
By 1905, the existing facilities and infrastructure could not meet Calgary’s demand for electricity. Hydroelectric power was still the cheapest option available, and the region needed all it could get. New corporations entered the race to develop southern Alberta’s hydro potential. In 1911, Calgary Power (which would evolve into TransAlta Utilities over the next century) completed the province’s first major hydroelectric plant in order to provide Calgary with badly needed electricity. This plant was constructed at Horseshoe Falls on the Bow River, about fifty miles upstream from Calgary.
Horseshoe Dam Hydroelectric Plant
Alberta’s first large-scale hydroelectric plant, Horseshoe Falls, came about through the intersection of two powerful and complementary forces that defined early twentieth-century southern Alberta. The first was demographic: the population of southern Alberta was surging with the immigration boom of the early twentieth century. The population of Calgary exploded, and by 1905, demand for electricity was placing an enormous strain on the city’s supply; in short, the city desperately needed new sources of electricity. This fused perfectly with the second force—the momentum of capitalist investment and economic growth. In the early 1900s, Alberta experienced one of the greatest economic booms in its history, and businessmen from across Canada eagerly sought out investment opportunities to capitalize on the province’s extraordinary prosperity. Given the tremendous demand for electricity, the development of hydropower seemed to offer entrepreneurs an outstanding investment opportunity.
In 1907, two Calgary businessmen (W. M. Alexander and W. J. Budd) formed the Calgary Power and Transmission Company and negotiated the right to build a hydroelectric plant at Horseshoe Falls. Despite the site’s ideal location, the two men had severely underestimated the engineering challenges and huge expense of the project. The pair had signed a contract to provide Calgary with electricity by 1909, an obligation they were unable to meet. In that year, wealthy financier Max Aitken stepped in and purchased the company (and its associated rights), which he renamed Calgary Power (now TransAlta). Construction on the Horseshoe Dam project began in 1909, but faced a variety of serious challenges, including floods, accidents and, in 1911, an outbreak of smallpox. While construction had been slow and plagued with challenges, the plant was finally finished on May 21, 1911—not a moment too soon, given the city’s power shortage.
The Horseshoe Hydroelectric Dam’s four horizontal Francis turbines gave the facility a peak capability of 14,000 kilowatts and provided the city’s budding industry, its growing population and the new CPR repair facilities a plentiful and cheap source of power. The plant would later be joined by four others on the Bow River watershed and would continue to provide reliable power for a century (and still counting).
Evolution of an Industry (1913-1945)
Even before the Kananaskis project was finished, engineers began to address the most significant problem with hydro development on the Bow River—irregular water flow. Hydroelectric dams operate most efficiently when the flow of the river is steady and consistent, but the water levels of the Bow River (and the speed at which they travel) fluctuate wildly between spring and winter. The best available solution was water storage and regulation—build a dam and a reservoir to divert and store water to be released during periods of low river flow. In 1912, the issue was partially solved with the construction of a dam at Lake Minnewanka, creating a reservoir that allowed for some regulation of the river. This alone was not sufficient to solve the problem, however, and advocates of hydroelectricity in Alberta eagerly sought permission to build more dams and create more storage reservoirs.
For the first time, however, advocates of Alberta hydropower came up against organized opposition to further expansion. The main point of contention between advocates and opponents of hydropower was the fact that development along the Bow River had taken place in Rocky Mountain National Park. As detailed by Christopher Armstrong and H. V. Nelles in their book Wilderness and Waterpower, substantial opposition to further hydro development within the boundaries of the national park emerged in the 1920s. Tourism was big business, and opponents of hydropower development argued that more dams and storage facilities would detract from the landscape and potentially undermine the region’s appeal as a tourist destination. Advocates of hydropower, including Calgary Power, insisted that further expansion was necessary to meet the demand for electricity in southern Alberta. This struggle between competing economic interests was further complicated by a struggle between the federal and provincial governments regarding jurisdiction over the park. The end result was to stall several proposed projects in the 1920s, and there was very little further development within the boundary of the national park.
Ghost Hydroelectric Dam
After a short economic downturn following the First World War, Alberta’s economy returned to the booming prosperity that had characterized the pre-war years. By 1925, electricity consumption was surging, with Calgary’s requirements almost doubling in only a few years. New sources of energy had to be found, and the answer was in hydroelectricity. At that time, hydro was still considerably cheaper than coal-power generation and would remain so for another quarter century.
Calgary Power was the province’s main energy supplier, already operating the Horseshoe and Kananaskis Falls plants west of Calgary along the Bow River. Further expansion within Banff National Park was complicated by issues of jurisdiction, so the company turned to the confluence of the Bow and Ghost Rivers as the location for its next project. After finalizing a lease on the territory in 1929, Calgary Power began construction of the Ghost Dam and Reservoir. The project was significantly larger than both Horseshoe and Kananaskis, and when it was brought online, the Ghost facility had an output of 28 MW, nearly doubling the company’s total capacity and providing a significant boost to provincial power generation. Once completed, high voltage transmission lines were stretched out to Edmonton, and for years this line was the backbone of Alberta’s electrical system.
The timing of this project was nearly disastrous. While demand and prices had been high in the booming 1920s, Ghost Dam came online just as the Great Depression was wreaking havoc with the provincial and global economies. The depression slowed economic activity in every sector of Alberta’s economy, and soon power demand leveled off and began to drop. It was expected that the heavy borrowing needed to build the dam would be paid off with high usage and prices, but the economic slowdown had created a risky debt load with rapidly falling demand for power. Ultimately, it would take the company years to pay off the expenses it had incurred and to find new markets for all the excess power it now had. Today, the Ghost Hydroelectric Dam has nearly doubled its generating capacity to 51 MW.
Post World War II Hydro Developments
After the war, the need for new generating capacity remained strong. Many expected a collapse, but it failed to materialize. In fact, the economy was booming and demanding ever more power. The post war years, therefore, saw an aggressive building program. By 1947, Calgary Power had completed its Barrier Generating Station on the Kananaskis River about 11 km (7 mi.) upstream from the Bow River. With a head of 43 m (140 ft.) and a capacity of 13,000 kW, the plant had added 12 MW of new capacity. It is reported to have been the first remotely-controlled hydroelectric plant in Alberta and among the first in North America.
To meet the dual purposes of generating hydroelectric energy and increasing the low winter flow of the North Saskatchewan River at Edmonton and downstream, Calgary Power carried out an intensive search for possible storage sites on the North Saskatchewan River and its tributaries. Three new projects were also brought online in quick succession. These were the new Spray Lakes, Three Sisters and Rundle dams with a combined capacity of 65 MW. Most of this new power was coming from the Spray Hydroelectric Dam with its 275 metre drop. In 1954, Calgary Power finished the 17 MW Bearspaw Hydroelectric Dam just west of Calgary and a third generator was installed at the Ghost Hydroelectric Dam, increasing its output to 51 MW. The next year the company had completed the last dams on the Kananaskis River, the Pocaterra Hydroelectric Dam, a 15 MW facility, and the Interlakes Hydroelectric Dam, a smaller 5 MW dam.
By the end of the 1950s, ideal sites for hydroelectric plants were rapidly diminishing. By this point a cubic metre of water through the Bow River system could generate power eight times before reaching Calgary, as the water would move progressively through a system of various dams and power plants. Without new spots for hydro power, power suppliers began to turn to steam-powered stations for additional expansion.
Despite the increasing amount of power generation focused upon coal and other fuels, hydroelectricity was far from finished in Alberta. The next phase of expansion took place in the 1960s when, under agreement with the provincial government, Calgary Power undertook its largest hydroelectric project. It constructed the Brazeau Hydroelectric Dam and reservoir on the Brazeau River, a tributary of the North Saskatchewan. The dam was completed in 1963 and the first generating unit was installed at the power plant in 1965, adding 355MW of generating capacity to the Calgary Power System.