Hydroelectric Dam vs Run Of River vs Pumped Storage Hydro Energy: Comparison

There are several different types of hydro energy set ups used to generate electricity globally.

In this guide, we compare hydroelectric dams vs run of river vs pumped storage hydro energy projects and power plants.

We look at what each is, their differences, and examples of each being used in the world.


Summary – Hydroelectric Dam vs Run Of River vs Pumped Storage Hydro Energy

What Hydro Energy Is

Hydro energy is the use of running water to create electricity


Prominence Of Hydropower

Hydropower as a whole produces the most electricity of any renewable energy sourceroughly around 50% of all electricity produced by renewable energy sources globally


Main Types Of Hydro Energy

There’s several different types of hydro energy:

– Hydroelectric dams

Built on rivers with an impoundment facility, dam and reservoir

Dam hydro power usually produces the most electricity


– Run of river

May or may not have a dam – but can simply use flowing water without a dam or reservoir


– Pumped storage hydro

Using two reservoirs or water – one on a higher level and one on a lower level


Other Categories Of Hydro Energy

All the above types of hydro energy can be divided into:

– Hydro energy power set ups that use dams and reservoirs

– And, those that don’t use dams and reservoirs


They can also be divided into the different sizes of hydro power plant (depending on the amount of electricity production capacity they have):

– Large

– Medium

– Small 


Future Projections For Hydro Energy

Hydropower is expected to expand into the future, particularly in developing economies

But, growth isn’t expected to be as strong as the last 5 years to one decade (investment and expansion will mostly be in solar, wind, and bioenergy)

Large and mega sized hydro projects might have some uncertainty regarding their funding, planning and construction – so growth and added capacity of hydro energy can be dependent on this


Potential For New Hydro Energy Sites

According to recent studies, there is potential for many new pumped storage hydro sites worldwide – pending on-site feasibility checks.


Potential For RenewablePumped Storage Hydro In The Future

In the future, there may be potential for pumped storage hydro to:

– Be able to use more renewable energy sources for pumping instead of fossil fuels

– And, also be able to act as a storage for surplus renewable energy in some instances


Pumped storage hydro might also be able to act as a backup to intermittent energy like solar and wind in the future, depending on different variables.


What Is Hydro Energy?

Hydro energy is the use of running water to create electricity


The Different Types Of Hydro Energy, & How Each Works

Dams & Reservoirs vs No Dams & Reservoirs

Hydro energy might be broadly categorised into two types of projects:

– Hydro energy with dams and reservoirs

Hydro on the utility scale (hydro energy produced for electricity and energy utilities), and also large hydro usually involves dams and reservoirs


– And, hydro energy without dams and reservoirs

Local community/village scale hydro, small hydro, and run of river hydro usually doesn’t involve a dam or reservoir


Dam vs Run Of River vs Pumped Storage

Beyond the above broad categorisation, utility scale hydro power plants can be divided into different types of hydro.

From energy.gov, those types are:

– Impoundment/Dam (using an impoundment facility) 

[Is a] dam [that] stores water in a reservoir.

[To generate electricity …] water is released from the reservoir through turbines, which activate a generator, and [then] produces electricity

Dams can [serve other purposes too,] such as preventing flooding.


– Diversion/Run Of River

[Involves channeling part of a river] through a canal or penstock [and it may, or may not use a dam]

[It helps if the river has a consistent flow, otherwise, without a storage reservoir, energy will be variable and not consistent]


– Pumped Storage

Pumped storage has both an upper, and also a lower water reservoir.

[Water is stored in the lower reservoir]

[When there’s a need to generate electricity, the water is pumped up to the upper reservoir]

[The water is then released back down to the lower reservoir, and on the way, it passes through turbines]

[The turbines activate a generator, which] produces electricity

[Pumped storage can actually store energy in the form of water, so, it can be a good backup to wind and solar energy for example]


Diversion and run of river hydro generally might have a less negative environmental and social impact in several ways compared to large hydroelectric dams.


Potential For Renewable Hydro Energy In The Future

Something else to note is that renewable hydro energy might be becoming a type of hydro energy in the future.

Currently, pumped storage hydro uses fossil fuels to pump water up to it’s top reservoir.

In the future, renewable energies like wind and solar might provide the electricity to pump and power hydro power stations.

It’s also possible this type of hydro energy could act as a storage for surplus hydro energy in the future.


Large vs Small Hydro Energy Projects – The Different Sizes & Capacities

Globally, there’s no official definition of small, medium and large hydro

But, each country might refer to the different sizes of hydro plants and projects according to these categories.

Size usually refers to the energy/electricity generation capacity of the hydro plant.

All of the largest hydro projects tend to be dams as they tend to produce the most electricity.

This might especially be true when you look up the largest hydro plants in the world

The Three Gorges Dam for example produces up to 22,500 MW – one of the largest energy generation capacities in the world.


wikipedia.org gives a broad idea of how the different sized hydro plants might be categorised by specific electricity generation thresholds:

Large – 10 GW (10,000 MW) and over

Small – 10-30 megawatts (MW)

Micro and Pico – in the kW range


sciencealert.com also notes how some of the largest pumped storage hydro energy setups have some of the largest energy capacities in the world.

sciencealert.com notes that:

… some of the biggest pumped storage plants have a capacity of 1000 to 3000MW.

New potential pumped storage sites discovered in recent studies have potential capacity to hold 2-150 GWh of energy


2 GWh might convert to roughly 2000 MWh


Hydroelectric Dams

From wikipedia.org:

[Hydroelectric dams can range …] from 1000 all the way up to 22,500 MW of capacity. 


Run Of River

From wikipedia.org:

[Worldwide, run of river projects might vary in size, from] 16MW of capacity … up to 11,233 megawatts of capacity


Pumped Storage Hydro

From wikipedia.org:

[Pumped storage hydro sites range] between 1000 to 3000MW of capacity.


Differences In The Different Types Of Hydro Energy

Some of the main differences in the different types of hydro energy might include cost, efficiency, and capacity. 


Large Hydroelectric Dams

Large Hydroelectric dams:

– Tend to be the most expensive to construct

– Tend to have the greatest capacity for production (so, costs and returns can average out over the long term)

– Tend to have the highest social and environmental impact


Pumped Hydro

Pumped hydro storage sites:

– Require land clearing

– And, once in use, may use fossil fuels to pump water up to the higher reservoir


Dam & Reservoir

Dam and reservoir hydro plants:

– Offer energy storage

– Can ramp up quickly in terms of energy generation in times of peak demand – this is in opposition to run of river hydro energy that requires water be flowing (depends on a river that runs year round) in order to produce electricity


Run Of River

– Run of river and small scale hydro that don’t need dams and reservoirs tend not to be as intrusive or destructive on the natural landscape as large hydroelectric dams


Mixed Plant vs Renewable Hydropower Electricity Generation

In 2016, electricity generation from hydro power was:

Mixed Plant – 4,048,420

Renewable Hydropower – 0

– irena.org


So, it appears as though renewable hydropower needs more development in order to be able to generate electricity at all in the future. 


Future Projections For Hydro Energy

Projections For Total Hydro Growth

Hydropower capacity is expected to increase 125 GW [heading up to 2023] – [but this is] 40% less than [the increase] in 2012‑17 (iea.org)


Projections For Pumped Storage Hydro Growth

[It is thought there could be a lot of potential in pumped storage hydro in the future as new scans and studies of the globe have found hundreds of thousands of new potentially usable sites for pumped storage hydro]

[Pumped storage hydro has the advantage of providing energy storage and baseload power as a complement to solar and wind energy]

– sciencealert.com


One-fifth of overall growth (26 GW of the total 125 GW) is from pumped storage hydropower (PSH) projects (iea.org)


Countries With The Largest Hydro Projects

Hydroelectric Dams

From wikipedia.org:

China features heavily, having some of the biggest hydroelectric dams in the world, including the biggest – Three Gorges Dam, which is on the Yangtze River.


Run Of River Hydro Power Plants

From wikipedia.org:

[There might be high] variance in capacity of the major examples of run of river hydro plants globally.

[They range …] from 16MW of capacity at a station in British Columbia, Canada, all the way up to 11,233 megawatts of capacity at Belo Monte Dam in Brazil.


Pumped Storage Hydro

From wikipedia.org:

China, the US, Japan, Australia, Spain and France has some of the [pumped storage hydro sites] with the largest capacity.


Global Installed Capacity, Production & Consumption Of Hydro Energy

Worldwide, hydro energy installed capacity, production and consumption stats are:

At the end of 2018, made up 50% of installed capacity for renewables

At the end of 2018, made up 15.8% of total global electricity production

At the end of 2016, was the most consumed renewable energy source for electricity


Between 2012 to 2018, solar PV led all renewables in annual additional installed capacity by a wide margin, followed by wind energy, hydropower, and all other renewables as a group behind that (including solar CSP/thermal) (vox.com)


Countries That Generate The Most Hydropower

At the end of 2015, the leading hydropower generating countries were China, the US, Brazil, Canada, India and Russia (worldenergy.org)


Investment In Hydro Energy

In 2016, investment in small hydro lagged behind solar, wind and biomass globally.

Major hydro project investment can vary by year and can be unpredictable.


Cost Of Hydroelectricity 

Overall, hydroelectricity has been one of the cheapest forms of renewable energy (although solar and wind are challenging it)




1. https://www.irena.org/hydropower

2. https://www.energy.gov/eere/water/types-hydropower-plants

3. https://en.wikipedia.org/wiki/Hydroelectricity

4. https://www.vox.com/energy-and-environment/2019/6/18/18681591/renewable-energy-china-solar-pv-jobs

5. https://www.bettermeetsreality.com/installed-capacity-production-consumption-of-renewable-energy-worldwide-by-country-by-source/

6. https://www.bettermeetsreality.com/countries-that-invest-the-most-in-renewable-energy-what-they-invest-in/

7. https://www.bettermeetsreality.com/the-different-types-of-renewable-energy-sources-with-examples/

8. https://www.iea.org/renewables2018/power/

9. https://www.iea.org/newsroom/news/2018/october/modern-bioenergy-leads-the-growth-of-all-renewables-to-2023-according-to-latest-.html

10. https://en.wikipedia.org/wiki/List_of_conventional_hydroelectric_power_stations

11. https://en.wikipedia.org/wiki/Run-of-the-river_hydroelectricity

12. https://en.wikipedia.org/wiki/List_of_pumped-storage_hydroelectric_power_stations

13. https://en.wikipedia.org/wiki/Hydroelectricity

14. https://www.sciencealert.com/scientists-spot-530-000-potential-pumped-hydro-sites-to-meet-all-our-renewable-energy-needs

15. https://www.cnet.com/news/if-renewable-energy-can-power-entire-countries-why-isnt-everyone-doing-it/

16. https://www.abc.net.au/news/2017-02-03/pumped-hydro-and-its-potential-in-sa-explained/8233342

17. https://www.worldenergy.org/data/resources/resource/hydropower/

18. http://www.wvic.com/content/facts_about_hydropower.cfm

19. https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity

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