Energy Past, Present and Future: Hydroelectricity

By Arjun Bhatia

Hydroelectricity is a source of renewable energy that converts the power of flowing water into useful electricity; while this particular technology has only been around for the last 200 years, its base design is far older. The concept of hydro energy has been around for millennia, making contact with numerous civilisations, and at each step, becoming refined into a technology that can power the modern world.

The first recorded design for a turbine is thought to be the work of the Roman engineer, Vitruvius, who drew plans for a simple water wheel around 0 CE. The wheel could be used to perform many manual tasks, however, it would still take many centuries for this technology to become widespread. Around the same time, the ancient Chinese engineer, Tu Shih, conceptualised a horizontal water wheel, which soon became a critical part in ancient Chinese industries, being used for smelting ore (Figure 1), grinding grain, and hulling rice. For around 13 centuries, these innovations travelled west, over the Silk Road, the main trade route in ancient Eurasia, becoming a staple of medieval life and industry [1].

Figure 1: Chinese work of 1313 AD detailing a waterwheel to power smeltery bellow, similar to that designed by Tu Shih. Original image can be found here. [1]

It would not be until the 1800s that hydropower would start being used to generate electricity. In 1849, American engineer James Francis created what would become the most widely-used hydroelectric turbine, the Francis turbine [2]. The Francis turbine was an extremely robust design, adaptable to nearly any orientation, flow rate, and pressure. The key feature of this design was the spiral-shaped casing around the turbine, to maximise the amount of energy that could be harvested from the water before finally draining it along the turbine’s axis [3]. Be sure to check out this month’s Tech Breakdown to learn more hydro power generation!

Figure 2: Francis Turbine top (A) and front (B) views showing water flow. Original image can be found here. [3]

Around the same time, Millwright Pelton created his own turbine: the Pelton wheel. It essentially took the original waterwheel, improved the shape of the blades to capture more energy, and redirected the input flow as to decrease splashing. Though not able to generate as much power as the Francis turbine, this design had its own advantages. They were far cheaper and simpler to build, and are extremely efficient for low flow rates [4].

Figure 3: Pelton Wheel concept drawing. Original image can be found here. [5]

Between these two designs, the next century saw a boom in the construction of hydroelectric plants. Across North America, massive generating stations went up. These were further improved by the construction of dams, allowing the stations to control the flow of large volumes of water and change the power output based on current demand [6]. The first major stations were built in North America, namely in Ontario and Michigan, before spreading across the globe to Western Europe and the Soviet Union. In addition, hundreds of small-scale generators popped up around the world. In 1984, the largest generator opened between Brazil and Paraguay, only to be surpassed by China’s Three Gorges Dam (figure 5) in 2006 [7][8].

Figure 4: Croton Dam, Michigan, was built in 1907 and is one of the first hydroelectric dams in North America. Original image can be found here [9].

Today, China and Brazil are the top two producers of hydroelectric power in the world, with Canada just behind them [10]. Canada itself produces 60% of its electricity through hydroelectric means and even exports some of this power to the United States, as they begin to shift away from oil and coal plants [11].

Figure 5: Three Gorges Dam hydroelectric plant. Original image can be found here [8].

While North America and Europe begin to look towards other forms of renewable energy, hydroelectricity is particularly attractive for rapidly developing countries in Asia and South and Latin America [7]. Not only is hydropower renewable, it is also extremely efficient, peaking at 95%, making it an extremely cost-effective choice for any country looking to expand its grid [12]. China and Brazil are prime examples of this, but many smaller countries such as Malaysia, Indonesia, Thailand, Myanmar, Venezuela, Peru, Ecuador, and Haiti are also turning to hydroelectric systems to meet their growing demand [13], [14]. One final note is that hydroelectricity offers these countries opportunities to stimulate their economies through energy exports. Laos, for example, exports two-thirds of all the hydropower it generates, providing significant revenue to its growing economy [15].

The journey of hydropower has been one 2000 years in the making, taking root in ancient civilizations, and being passed around the world. At each step, it was iterated on and improved, allowing it to play the role it does today. Hydropower continues to stand as a clean source of electricity, both cost- and energy-efficient, and an economic boon for nations and people around the world, with room to grow for centuries to come.

References

[1]    “WaterHistory.org.” http://www.waterhistory.org/histories/waterwheels/ (accessed Nov. 25, 2020).

[2]    “History - National Hydropower Association.” https://www.hydro.org/about/history/ (accessed Nov. 25, 2020).

[3]    “Francis Turbines - an overview | ScienceDirect Topics.” https://www.sciencedirect.com/topics/engineering/francis-turbines (accessed Nov. 25, 2020).

[4]    “Pelton Impulse Water Wheel | ASCE.” https://www.asce.org/project/pelton-impulse-water-wheel/ (accessed Nov. 25, 2020).

[5]    “Pelton and turgo turbines - Renewables First.” https://www.renewablesfirst.co.uk/hydropower/hydropower-learning-centre/pelton-and-turgo-turbines/ (accessed Nov. 25, 2020).

[6]    “Types of Hydropower Plants | Department of Energy.” https://www.energy.gov/eere/water/types-hydropower-plants (accessed Nov. 25, 2020).

[7]    “History of Hydropower.” https://www.hydropower.org/discover/history-of-hydropower (accessed Nov. 25, 2020).

[8]    “Three Gorges Dam | Facts, Construction, Benefits, & Problems | Britannica.” https://www.britannica.com/topic/Three-Gorges-Dam (accessed Nov. 25, 2020).

[9]    “Croton | Michigan.” https://www.michigan.org/city/croton#?c=44.4299:-85.1166:6&tid=703&page=0&pagesize=20&pagetitle=Croton (accessed Nov. 25, 2020).

[10]  “Hydroelectric Power Water Use.” https://www.usgs.gov/special-topic/water-science-school/science/hydroelectric-power-water-use?qt-science_center_objects=0#qt-science_center_objects (accessed Nov. 25, 2020).

[11]  “Canadian Hydropower.” https://hydro.canadiangeographic.ca/ (accessed Nov. 25, 2020).

[12]  “Resource Overview: Hydropower in Canada: Past, Present, and Future - Hydro Review.” https://www.hydroreview.com/2009/10/01/resource-overview/ (accessed Nov. 25, 2020).

[13]  S. Tang, J. Chen, P. Sun, Y. Li, P. Yu, and E. Chen, “Current and future hydropower development in Southeast Asia countries (Malaysia, Indonesia, Thailand and Myanmar),” Energy Policy, vol. 129, pp. 239–249, Jun. 2019, doi: 10.1016/j.enpol.2019.02.036.

[14]  “Hydro Powers Latin America - Renewable Energy World.” https://www.renewableenergyworld.com/2012/06/21/hydro-powers-latin-america/#gref (accessed Nov. 25, 2020).

[15]  “International Hydropower Association.” https://www.hydropower.org/country-profiles/laos (accessed Nov. 25, 2020).