What Is Using Water For Power Called?

What is Hydroelectric Power?

Hydroelectric power refers to the process of generating electricity by harnessing the kinetic energy of flowing or falling water. In a hydroelectric power plant, the kinetic energy of moving water is converted into mechanical energy by turning turbines, which then spin generators to produce electricity.

The basic principle behind hydroelectric generation is that if water can be piped from a higher elevation reservoir down to a turbine, the water’s gravitational potential energy gets converted to kinetic energy as it falls. The kinetic energy of the flowing water is then captured by turbine blades and turned into rotational mechanical energy. This rotation spins a shaft connected to a generator to produce electricity.

Hydroelectric power is considered a renewable energy source because it relies on the water cycle, where water evaporates, forms clouds, precipitates, and collects in higher elevation basins, just to repeat the cycle again. The fuel used to generate electricity – the flowing water – is continually replenished through this natural process.

How Hydroelectric Power Plants Work

Hydroelectric power plants convert the energy of flowing water into electricity. The process begins with water at a higher elevation flowing down towards turbines. The moving water contains kinetic energy. When the water flows through the hydroelectric plant’s turbines, the turbines spin. The turbine blades are connected to a shaft that rotates when the blades spin. This spinning turbine converts the kinetic energy of the flowing water into mechanical energy. The turbine shaft is connected to a generator. As the shaft spins inside the generator, it converts the mechanical energy into electrical energy. The generator works through electromagnetic induction – when the magnets spin inside copper wire coils, it produces an electric current. This electricity is sent through transmission lines to homes, buildings, and the electrical grid

At hydroelectric dams, a reservoir of water is held back by the dam. This reservoir contains potential energy from the elevation difference. Gates in the dam open to allow water from the reservoir to flow down through intake pipes under high pressure. The water flows through the hydroelectric plant’s turbines at the bottom of the dam. After passing through the turbines, the water exits through a spillway or tailrace. Dams allow hydroelectric power plants to control when and how much water flows through for electricity production.

See: (https://www.energy.gov/eere/water/how-hydropower-works)

History of Hydroelectric Power

The first hydroelectric power plant was built in the late 19th century. In 1881, the Schoelkopf Power Station No. 1 began operation in Niagara Falls, New York, marking one of the earliest examples of hydroelectric power. This pioneering plant initially powered local industry and street lighting.

In the late 1800s and early 1900s, hydroelectric power saw rapid growth and early adoption in North America and Europe. Large hydroelectric projects were constructed to provide electricity for industrialization and urbanization. Major projects included the Edward Dean Adams Power Plant at Niagara Falls in 1895, which powered the city of Buffalo, New York via the world’s first large-scale generation and transmission of AC electricity. Another landmark was the Hoover Dam, completed in 1936, which provided hydroelectricity and controlled flooding in the southwestern United States.

Massive hydroelectric projects were constructed around the world in the early 20th century, including the Wilson Dam in Alabama in 1924, the La Grande complex in Canada in the 1930s-40s, and the Kariba Dam on the Zambezi River in Africa in the 1950s. This represented the large-scale building of hydroelectric infrastructure that helped accelerate industrial development globally.

Advantages of Hydroelectric Power

Hydroelectric power has several key advantages that have made it one of the leading renewable energy sources worldwide:

Renewable Energy Source

Hydroelectric power is considered a renewable energy source because it relies on the water cycle. Rain and snow replenish the water used to generate electricity at hydroelectric dams and facilities, allowing for a continuous supply of power generation (https://www.energy.gov/eere/water/benefits-hydropower).

Produces No Direct Waste or Pollution

Unlike fossil fuel power plants, hydroelectric plants do not burn fuel to generate electricity, so they produce no air pollution or greenhouse gas emissions. The power generation process itself is clean and does not create any toxic byproducts (https://www.enelgreenpower.com/learning-hub/renewable-energies/hydroelectric-energy/advantages).

Reliable and Flexible Baseload Power

Hydroelectric facilities can provide steady, reliable electricity to meet baseload demand. The flow of water can be controlled through the dam to generate power on demand. Hydroelectric generators can also be switched on and off quickly to meet fluctuating energy needs (https://www.usgs.gov/special-topics/water-science-school/science/hydroelectric-power-advantages-production-and-usage).

Long Lifespan for Facilities

Compared to other power plants, hydroelectric facilities and dams are extremely long-lived. With regular maintenance, dams can remain operational for over 100 years. This provides many decades of reliable clean energy production.

Disadvantages of Hydroelectric Power

While hydroelectric power has many benefits, there are some notable drawbacks as well. Some of the main disadvantages of hydroelectric power include:

High Upfront Costs: Constructing hydroelectric power plants requires substantial upfront investment, with costs frequently running into the billions of dollars. Massive dams, reservoirs, tunnels, and turbines all require major capital outlays before the plant can even begin producing electricity (Kiwi Energy). This long-term payback period makes financing hydro projects challenging.

Impact on Rivers and Wildlife Habitats: The reservoirs created by hydroelectric dams flood large areas, altering the local environment and ecosystem. Fish migration routes can be blocked, disrupting spawning. The flooding of natural habitats also causes significant displacement and destruction of plant and animal species (Earth.org).

Limited to Suitable Geography: Generating hydroelectricity relies on water flow, so it can only be harnessed in locations with the right hydrologic conditions, usually with river elevation changes that allow gravity power. This geographic limitation restricts where hydro plants can be built.

Drought Can Reduce Output: During periods of low rainfall and drought, the amount of water available for hydroelectric generation can be significantly reduced. This leads to lower electricity output from the plant during those times.

Major Hydroelectric Projects

Some of the largest and most famous hydroelectric dams in the world include:

The Hoover Dam in the United States, built in the 1930s, was one of the largest concrete structures in the world at the time. With a height of 726 feet and a generating capacity of over 2,000 megawatts, Hoover Dam impounds Lake Mead and provides water and power to several states in the Southwest U.S.

The Grand Coulee Dam in Washington state, also built in the 1930s, is over 5,200 feet long and 550 feet high. Grand Coulee was the largest power station in the U.S. for decades, with around 6,800 megawatts of generating capacity.

The massive Three Gorges Dam in China, completed in 2006, spans over a mile across the Yangtze River and stands over 600 feet tall. With 22,500 megawatts of capacity, it is the largest hydroelectric project ever built.

The Itaipu Dam on the border between Brazil and Paraguay is one of the largest operating hydroelectric facilities, generating around 14,000 megawatts from a height of just over 700 feet.

Small-Scale and Micro Hydro Projects

Small-scale hydroelectric projects generate under 10 megawatts of power, while micro hydro projects generate under 100 kilowatts. These small dams and hydro systems provide power for isolated homes, villages, and even small industries. Micro hydro systems are often an effective way to provide electricity to rural or remote locations that are not connected to the main power grid.

Small dams can be built on streams and irrigation canals with relatively high heads of water. The water passes through a pipe and pushes against turbine blades that spin a generator to produce electricity. Homeowners and villages can utilize micro hydro systems by diverting a portion of a river or stream through a pipe and turbine generator [1]. Planning involves assessing the head and flow of water to determine potential power output [2]. These small systems provide clean, renewable power from a consistent source.

Future of Hydroelectric Power

While most suitable sites in developed countries have already been utilized, the future for hydroelectric power generation remains promising. Upgrading existing infrastructure provides opportunities to expand capacity and increase efficiency.

Many existing dams were built decades ago and can benefit from modern turbine technologies that convert more energy for less cost. Retrofitting dams with advanced equipment, such as variable speed turbines, can boost output. For example, adding variable speed capabilities to the 18 turbines at the Hoover Dam in the United States increased peak capacity by enough to power Los Angeles for a year [1].

Developing countries are investing in new large-scale hydroelectric projects to meet rising electricity demand. The countries with the most potential for new hydro development are China, India, Brazil, the Democratic Republic of the Congo, and Russia. Large dams are controversial, but proponents argue they provide clean renewable energy to growing populations.

Overall, while the best sites in developed nations have already been harnessed, upgrading existing infrastructure and building new capacity in developing countries will shape the future of hydropower generation worldwide.

Hydroelectric Power Usage Worldwide

Hydroelectric power provides about 16% of the world’s electricity, making it an important renewable energy source. China, Brazil, Canada, the United States, and Russia are the top countries in hydroelectric generation.

According to Statista, as of 2022 China generates the most hydroelectricity in the world, producing over 1,230 terawatt-hours annually. This accounts for over 30% of global hydroelectric generation. With abundant water resources and suitable geography, hydro plays a major role in China’s renewable energy strategy.

Other leading countries are Canada (346 TWh), Brazil (363 TWh), and the United States (250 TWh). Large emerging economies like India are also expanding hydroelectric capacity to meet growing power needs.

In terms of percentage of domestic electricity production from hydro, countries like Canada and Norway generate over half their power from hydroelectric. Overall, hydroelectricity remains an essential renewable energy source worldwide, led by major generators like China.

Comparison to Other Renewables

When comparing hydropower to other renewable energy sources like wind, solar, biomass, and geothermal – hydro has some advantages and disadvantages.

Hydroelectric power can generate electricity more reliably than intermittent sources like wind and solar since it does not depend on weather conditions. The flow of water in hydroelectric dams can be controlled, allowing electricity to be generated on demand. This makes hydropower more dispatchable than wind or solar (1).

However, hydropower facilities typically have less environmental impact than other renewable options like biomass, which emits CO2, or geothermal, which can release harmful gases. Most hydro dams are powered by natural water flow and do not require burning fuels (2).

On the other hand, hydroelectricity is less flexible than natural gas power plants, which can more easily ramp electricity generation up or down to meet changing demand. Hydro plants have more limitations in how quickly their output can be adjusted (3).

Overall, hydropower offers renewable baseload power more consistently than some sources but with fewer emissions than others. It strikes a balance between reliability and sustainability.

(1) https://www.eia.gov/energyexplained/hydropower/advantages-and-disadvantages-of-hydropower.php
(2) https://www.energy.gov/eere/water/benefits-hydropower
(3) https://www.cnbc.com/2022/06/02/why-hydropower-is-the-worlds-most-overlooked-renewable.html