Is it time to rethink Hydropower as Renewable energy?

First, let us find out what exactly is renewable energy…

Renewable energy is an energy/power drawn from a source, which can be replenished constantly on its own. This renewable energy is considered as more efficient in comparison to the exhaustible non-renewable energy sources such as fossil fuels, gases, which have a negative environmental impact, as renewable energy is believed to never run out of energy. Renewable energy includes natural sources such as wind power, solar panels, geothermal, wave and tidal power, and many others among which hydropower as renewable energy still remains in dilemma…

What is Hydropower?

When power/electricity is generated capturing 71% flowing water in our Earth’s rivers and oceans, the process is known as hydropower or hydroelectricity. The water, being part of the vast global water cycle, is never used up or reduced in the sun driven process and thus is considered as renewable energy.

How does Hydropower work?

Dams, a large barrier, constructed on the rivers at a certain height to raise the level of water, and control its flow play a major role. The elevation created by the Dam creates a gravitational force for turning the turbine when water is released. Mechanical energy created by the moving water spins rotors on a turbine. This turbine is connected to an electromagnetic generator, which produces electricity when the turbine spins.

Some Dams also contain an additional reservoir at their base where water is stored, which is to be pumped to the higher reservoir, for released when electricity is in demand. This is referred to as ‘Pump Storage Hydro’.

Now, talking about the dilemma


Apart from being cost-competitive and reliable for usage as base-load power for electricity, Hydropower does not produce greenhouse gases or other air pollution in the air we breathe, which is why it is also clean energy. Dams have also been used for land management and flood control, to store water for irrigation and agriculture, to provide recreation and navigation, and to address the management of aquatic resources. The reservoir in the Dams can also help overcome the water shortage by supplying adequate water for the population downstream.

And why not?

Initial effects

Building Hydropower plants decrease the water quality in and around the Dams. Hydropower plants also lead to sedimentation and thus increasing coastal erosion on beaches.

Effect of Sedimentation in dams



To tackle the rising carbon emissions by switching to renewable energy, the risk is being transferred to species as these facilities are installed in protected areas. Nepal has over 100 facilities within protected areas, while India has 74 under development in important conservation zones. Also, more than 17.6% of Hydropower plants have been built in key biodiversity areas such as protected regions and pose a threat to key natural habitats.

The large Dams distort the migration routes and thereby affect the habitat of various native aquatic lives disturbing their life cycle timing. They also cause changes in water level, temperature, which will affect the surrounding terrestrial and aquatic ecosystem.

Stagnant bodies of water in reservoirs act as sites for harmful algal blooms, which are toxic to people, fish, shellfish, marine mammals, and birds. Large Hydro Dams having fast-spinning turbine blades may cut the fishes acting as death-zone for fish. Even if they are successful in making past the turbine blade, the sudden pressure change can kill the fish.

The four different habitats associated with the projects, where Dams cause major ecological impacts are the estuary into which the river flows, the downstream reaches of the dammed river, the reservoir catchment, and the artificially created lake.

Effects on the Human population

Large dams can block the natural flow of water, increasing the chances of flood. And these Dam failures can sometimes be catastrophic, claiming the lives of those living downstream. The loss of agriculture, affecting food systems and water quality, and loss of wildlife and habitats are resulted from land clearance and removal of natural vegetation (deforestation) and often forcing thousands of people and the riverside communities to move out of their homes.

Other Greenhouse gas emissions

Hydro Plants are not completely free of greenhouse gas emissions. Carbon dioxide emission takes place during the construction, particularly due to the large quantities of cement used, operation and maintenance, and the decommissioning of the plant.

Way forward

According to the California-based company Natel Energy, partnered with Bill Gates’ investment firm, Hydropower is the most powerful renewable energy. And here is how they made a breakthrough venture towards making Hydropower more efficient…


To increase fish survival they created a compact, high-performance, inexpensive, blunt-edged curved thick turbine blade. This blade acts as an airbag for the fish ensuring minimal impact. When paired with better information about how much water will flow and when the whole solution works together to create a modern Hydropower system. And hence the migrating fish such as salmon or eel, which can get caught in the mechanism’s thin, sharp blades, can be saved. This design also removes the need for a “trash rack” – a fine screen traditionally used to capture debris at the entrance to the turbine, often installed to keep small fish out of the machinery. A Natel Energy turbine has already been installed in the wider ecosystem in Maine, US.

Fish friendly turbine mechanics


Small dams

Large dams are dangerous and uneconomic causing irreparable damage to the rivers they are built on. These Dams can destroy food sources, fisheries likely to be impacted with the potential loss of livelihoods, and may destroy thousands of species in these biodiversity hotspots.

Climate Resilient

As opposed to the traditional approach the Hydropower here aims to create climate-resilient Hydropower that can withstand the unpredictable change in rainfall and extreme weather conditions (droughts and floods). To achieve this turbine is paired with satellite technology which allows Hydropower plant operators to monitor changing watershed conditions such as the spring “green up” (i.e., when snow melts and plants begin to grow). Also, the software involves the use of machine learning to create real-time models of the surrounding landscape as per the conditions on the ground, which in turn enables more accurate water forecasts of the water flow.


Before human intervention and the creation of aqueducts and canals, most rivers were clogged with woody debris and beaver dams. The cascades that mimic beaver structures cause water to slow down, creating small ponds and wetlands which give sufficient time for water to seep into the ground, which in turn raises the water table. A higher water table means more groundwater storage, which helps watersheds ride out long stretches of drought.

Beavers create dams that make rivers spill and pool, helping to rewet the wider area


These linked distributed systems are specifically designed to restore river connectivity for fish and other wildlife, enhance water-supply sanitation and agricultural productivity and support the livelihoods and socio-economic development of local communities.

And when these smaller individual projects are linked into groups, operated in coordination can generate Hydropower eliminating the use of large dams.


Hydropower is the world’s most widely-used renewable energy source. If done sustainably, hydropower can work as a green fuel source with several side benefits, including flood control, irrigation, drought mitigation, and water supply. Also, electricity generated by Hydropower is cheap, easily stored and dispatched, and have greater production capacity powering homes and businesses for centuries to come.

Hydropower constituting 16%, is the most widely used renewable energy source for electricity generation and  represented 78% of Renewable electricity generation in 2015
Hydropower used for elecricity generation as of 2015 representing 78% of Renewable electricity generation


Hydropower plants can generate power to the grid immediately, they provide essential back-up power during major electricity outages or disruptions (water power has in fact been a boon to the high demand during the COVID-19 crisis).

So what do you think, can we reconsider installation of Hydropower or still confused? Let me know in the comment section below. It will be my pleasure to know your opinion on the same!

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7. Bergkamp G, Mccartney M, Dugan P, Mcneely J (2000) Dams, Ecosystem Functions and Environmental Restoration.




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