Hydropower is one of the oldest and largest renewable energy sources. It uses the natural flow of moving water to generate electricity. According to the International Renewable Energy Agency ( IRENA), its installed capacity is equivalent to all other renewable sources.
Hydropower plants make an essential contribution to combating climate change. They avoid the use of fossil fuels and reduce the emission of carbon dioxide and greenhouse gases.
But where does it all start? It originated from the water wheel, which transitioned from manual labor to mechanical energy. The use of this energy began with the first hydroelectric power plant, established in 1879.
About 150 countries make hydropower. In 2022, hydroelectricity generation increased by nearly 70 TWh, reaching 4,300 TWh. Today, approximately 62500 hydropower plants globally provide over 6000 gigawatts of electricity. In the Net Zero Emissions by 2050 scenario, hydropower will maintain an average annual growth rate of 4% in 2023-2030.
How do Hydropower Plants Work?
Most hydroelectric power plants have a reservoir, a valve to control the amount of water that flows out of the reservoir, and an outlet where the water ends up after flowing downwards. Water gains a certain amount of potential energy when stored in the reservoir before flowing downwards. The potential energy is converted to kinetic energy as water flows downhill. This water turns the turbine blades, producing electricity finally supplied to all homes.
There are four different types of hydroelectric power plants:
- Run-of-river hydroelectric power station
- Reservoir hydroelectric power plant
- Storage hydroelectric power plant
- Pumping or reversible power plant
Each produces energy to a great extent, helping to save the environment. Like any other energy source, hydropower also has advantages and disadvantages.
Advantages of Hydropower energy
1. Renewable Energy Source
Hydroelectric power is renewable, which means unlimited in time. This is because its sources, namely rivers and streams fed by the natural water cycle, are renewed. Hydroelectric power can run 24/7. It can run forever if its water source never runs dry.
Also, a hydroelectric power plant does not take water from the environment. In some countries, the source is abundant. They can produce a lot of energy there, thus making the country self-sufficient and sustainable.
2. Emission Free
The hydroelectric power plant is a clean source of energy. It does not emit any greenhouse gas or pollutant while generating electricity. Once in place, the power plants do not produce waste products during conversion.
This is not true for energy sources like nuclear or fossil fuels. They cause most climate change. Hydropower prevents the burning of 22 gallons of oil or 120 million tons of coal each year, helping contribute towards climate change.
3. Protects Biodiversity
Water storage in reservoirs fosters plant growth, attracting animals and preserving biodiversity. Channels and ramps near dams help fish to move. This allows them to swim up and down easily.
4. Cost-effective
Building a plant needs a lot of money, but water is the cheapest energy source. After building dams and installing turbines, maintenance costs are low. Also, engineers are using new technology to cut costs further.
5. Reduces Risk for Floods
A hydroelectric plant generates electricity and boosts area development. It also manages water release. This control is key during heavy rains to prevent floods.
6. Used for Irrigation
Hydroelectric power plants have a unique advantage for irrigation. They act as reliable water sources for irrigation purposes. By controlling the water flow, the crops always have access to water. Thus, the area around it is always green, and healthy crops are growing.
7. Ability to store water for peaked demand hours
The reservoirs also act as water tankers and store water. In a situation when there’s a shortage of water, they cover up for it. Dams constructed can also shut their gates and save the water for use when power is in high demand.
In times of heavy rains, the dams hold large quantities of water, avoiding flooding the area downstream, and in times of droughts, the water stored in these dams acts like a savior.
8. Consistent Power Generation
A pumped hydroelectric plant stores energy. When conditions are right, it uses excess wind or solar power to pump water into upper reservoirs. Later, on less sunny or windy days, the plant releases the water to generate electricity through turbines, thus making it easy for the power grid.
9. Contributes to Development
Hydroelectric power plants drive innovation and boost economies. A study in Wisconsin reveals that a medium-sized hydropower project provides recreational value to residents and visitors exceeding $6.5 million annually..
New tech is developing machines daily, ensuring that hydropower is more available. Modernization is helping to improve the capacity and generation of electricity.
10. It enhances tourist areas and water sports
The dams offer water activities like fishing, rafting, and boating. Hydro operators own a lot of land near the reservoirs. This land is open to the public for hiking, hunting, snowmobiling, and skiing.
11. It is a flexible source of energy
Adjusting water flow and electricity output is easy. These systems require very little energy to start, so much so that they can go from being idle to being in full power in just minutes and vice versa. The responsiveness depends on the type of turbine used and the management of water flown, which can be easily controlled.
Disadvantages of Hydropower Energy
1. High Capital Cost
Many hydroelectric power plants are expensive to build. They involve building dams, reservoirs, and power-generating turbines, making them a significant monetary investment.
While they can provide cheap electricity for 50 to 100 years, the upfront cost is significant. This, plus the fact that it will be harder to get land in the next few years, will make these projects more costly
2. Plant locations are limited
This is one of the biggest disadvantages of hydroelectric power. Building a hydroelectric power plant requires a specific geography. A steady flow of water from streams is needed, and the streams need suitable elevation drops to make electricity. This makes it difficult to attain many locations to construct such dams.
3. Risk to Natural Disasters
Modern planning and technology have reduced the risk of a natural disaster. Yet, old dams have been breached in the past. They gave under the weight of the lake. This has led to severe flooding. For example, The building of Hoover Dam triggered many earthquakes. It depressed the Earth in that area.
4. Impact on the Environment
Dams negatively impact the environment in many ways. Some of them are:
- They disrupt the natural migration routes of fish. This interrupts their lifecycles and limits their ability to reproduce.
- They affect the ecosystem, river flows, and water quality. This leads to habitat loss and affects both aquatic and terrestrial species.
- The construction of these dams often required the relocation of communities. This forces people to leave their homes, farms, and businesses.
- Building a dam can also affect the area’s water level.
For example, the building of the Aswan Damn Egypt has altered the level of the water table. This has led to slow damage to many ancient monuments, as salt and destructive minerals are deposited in the stonework. This change in the water table causes a ‘rising damp.’
5. Vulnerable to Climate Change
They are vulnerable to extreme climate change. This includes changes in rains, river flow, and extreme weather events. This affects the availability of water, making hydropower less reliable and sustainable. Droughts can stop electricity generation and change prices, making hydropower less stable.
Conclusion
Hydropower presents a valuable and renewable source of energy with numerous advantages including cost-effectiveness, minimal emissions, and diverse application from flood management to recreational use.
However, it also faces significant challenges,, such as high initial cost, environmental disruption, and geographical constraints.
As global energy demands continue to shift towards more sustainable sources, the role of hydropower is essential. It requires a thoughtful balance to maximize its benefits while minimizing its shortcomings.
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