Hydropower may not be The New Technology on the Block, but this old school tech may have a few tricks left in it. With other renewables like wind and solar gaining momentum, is there still room for growth? Are there any downsides hydropower has to address? And what about technology advancements … there’s some cool stuff coming our way.

This video is part of a two part collaboration with the YouTube channel, Terra Mater. Terra Mater explores environmental and conservation topics and want to inspire you to take care of our planet. I’m doing a deep dive on the technology behind hydropower and where it’s heading, and Terra Mater’s video does a wonderful job covering the environmental impacts of hydropower … but more on that later.

To give this context, and to make it clear why some of the new technology coming up is so important, we should take a quick step back. For more than a century, humans have been using the gravitational force of falling or flowing water to generate electricity at scale. This shouldn’t be news to anyone out there. During this time, there’s been technological innovations with turbines and other alternatives to extract more power from the force of water to supply the growing energy consumption of cities, industries, and farms.

The first use of hydropower was for mechanical milling by the Greeks thousands of years ago. But it wasn’t until 1882 that the first commercial hydroelectric power plant started to operate in Wisconsin, and since then water has been a powerful source utilized to generate electricity at a large scale all over the globe 1, 2.

While hydroelectric power is considered a renewable source since it doesn’t reduce the quantity of water that flows through the turbines, there are environmental concerns regarding the dams needed for the process. But I’ll get to that in a bit, as well as some of the cool technology trying to change that.

As I already mentioned, hydropower is the most widely used form of renewable energy in the world, accounting for about 17% percent of global electricity consumption 3. For example, in Europe hydropower accounts for more than 341TWh per year, equaling about 36% of the electricity generated from renewable energy sources 4. Up until 2019, it was the most extensive source of power among the renewables in the U.S and Canada, accounting for 59.6% 5, 6.

I’m sure pretty much everyone out there is at least a little familiar with the basics behind how hydroelectric power works, but in a nutshell it always comes down to turning a turbine. The gravitational force of falling or flowing water is used to spin a hydraulic turbine that’s coupled to the rotor of an electric generator. So, when the water flows through the turbine, it spins the blades creating kinetic energy, which is converted into electric power by that generator 7, 8.

There are three main types of hydropower plants currently in use that are putting this principle to work. The most common type is storage hydropower plants, also called impoundment facilities. A famous example of an impoundment facility is the Hoover Dam in the U.S. In these plants, a dam is used to control the volume of water stored in a reservoir. When energy is needed by the electric power system, the massive volume of water being held back is released from the dam, which flows downwards to the turbine 9, 10.

Water stored in reservoirs like this provide flexibility for producing electricity during peak demand. Some reservoirs can store a massive volume of water that’s enough to produce electricity for months, and they’re typically designed as multipurpose systems for controlling flooding, irrigation, storing water, and recreation 5.

The second type of hydropower plant is run-of-river (RoR) or diversion power plant. These may or may not use water storage. In RoR hydro projects, a portion of water flowing in the river is diverted towards hydraulic turbines to generate electricity, and then reunited back to the river. Typically, diversion power plants are constructed in mountainous regions to utilize natural water flow to generate more power 11.

While diversion power plants have a much smaller environmental footprint compared to impoundments, the downside is they don’t have energy storage, or a buffer, to pull from when there’s a rapid increase in power draw from the grid. 12.

The third type of hydropower plant is pumped storage (PSH), which has a small storage reservoir. These plants store energy by pumping water from a lower reservoir to a higher reservoir using cheap electricity in off-peak periods. Then, when electricity prices are high, or there’s a high-power demand, water is released back to the lower reservoir through turbines to produce electricity. It’s essentially a giant water battery that charges and discharges. According to the Office of Energy Efficiency & Renewable Energy, PSH installations account for 95% of all utility-scale energy storage in the U.S. 10, 13, 14, 15

When you take all of those into account there are more than 1,300 GW of installed hydropower capacity globally 16. But, how does it stack up to other power sources? When evaluating this type of thing, it’s not just how green or renewable it is, but also how reliable, accessible, and affordable it is. 17

It’s well established that greenhouse gas emissions in hydropower are much lower than those in fossil fuel power plants, such as coal, natural gas and petroleum. According to the International Hydropower Association (IHA), if current hydropower was replaced with burning coal, more than 4 billion metric tons of extra greenhouse gases would be released annually into the atmosphere, increasing global emissions by at least 10% 18. Score one for hyrdopower. However, as I’ve talked about in other videos, even renewable energy has environmental challenges.

Solar and wind have no or low environmental impact while operating, but the impacts caused by manufacturing and transportation to installation sites needs to be factored in. With solar panels the main environmental cost comes from manufacturing, installation, and disposal. Wind turbines share some of the same challenges, but can also present additional risks for wildlife during operation. I have videos that explore both of those topics in depth if you’re interested to learn more. Hydroelectric power, unfortunately, also does not come out unscathed when considering environmental impacts.

One way to quantify those impacts is through a Life-Cycle Assessment (LCA). LCA lets you identify the most significant impacts and the stages to be considered for improvements. One specific LCA for a hydropower plant in Amazonia showed that the construction phase represented the highest contribution to environmental impacts. From things like the steel used in the turbines, and concrete in the spillway, penstock, and powerhouse. Transporting of all equipment long distances also pointed to an increase in emissions 19. Much like the other renewables though, the operation causes no significant impact … as far as carbon emissions are concerned.

But what about the million dollar question? Literally. How much does it cost compared to other sources? The Levelized Cost of Electricity (LCOE) is a good apples to apples comparison between technologies. LCOE estimates take everything into account from building a facility to operating it over a specified period. It looks at things like capital costs, fuel costs, fixed and variable operations, maintenance (O&M), financing, and how much each plant type will be used.

In one study from the EIA that explored power sources coming online by 2025, hydropower is about 32% higher in cost than onshore wind and 59% higher than solar. But when compared to offshore wind, hydropower is 56% lower. It also beats out coal, advanced nuclear, combustion turbines, and biomass plants as well, which makes it not only very cost-efficient but also a good renewable, stable, and reliable power source 20.

Even though the cost for manufacturing and installing other renewables has been decreasing, hydroelectricity still has many advantages. The versatility and storage capacity of hydroelectric power plants make them a great counterbalance to the intermittence of solar and wind, which really need energy storage to make them more widely viable.

Compared to oil and natural gas, water is not subject to market fluctuations. Hydropower can be delivered quickly to satisfy peak demands, maintain the system voltage levels, and rapidly re-establishing power supply after a blackout. Hydropower also has low failure rates and a long life-cycle, all while producing tiny amounts of greenhouse gases (GHG) 21, 22, 23. However, there are concerns about hydropower, mainly regarding dam construction and impacts on wildlife.

Hydropower dams can have a sizable biological impact since the environmental footprint of these facilities disrupts a large area. Damming rivers affects local habitats and ecosystems and may lead to flooding, changes in water flow patterns, sediment build up, and fish migration problems. But there are technological innovations being developed to make hydropower cheaper, shrink the size and scale to reduce the environmental damage, and increase power capacity.

Getting back to new hydro power technologies, one good example is tidal energy, which utilizes natural water movements in the ocean to produce power underwater. The gravitational pull from both the moon and the sun result in high and low water surges that are used to spin turbines placed on the ocean floor 24. This is far less disruptive on the environment since you’re not building massive dams or redirecting rivers. One company, Simec Atlantis, is focusing on underwater turbines, which are very similar to wind turbines, but they can be much smaller due to the higher density of water compared to air. A test prototype system installed in Strangford Narrows, Ireland, in 2008, was composed of two 16 meter diameter turbines with a capacity of 0.6MW each. A wind turbine of equivalent power would have a diameter of 40 meters! While the Strangford Narrows project didn’t perform as well as expected — it only produced 15% of expected capacity — it was only a prototype and did provide valuable information for future revisions.

In fact, their latest turbine technology is a lot better. The turbines installed between the Island of Stroma and the North East coast of Scotland during the MayGen project had an increase in capacity from 0.6MW to 1.5MW. That’s nearly three times more powerful with almost the same 16-meter diameter turbines that were installed in Strangford Narrows 25, 26.

You can also find a good example of tidal energy in the U.S., with the the Roosevelt Island Tidal Energy (RITE) project, which Verdant Power has been running since 2002 in the East Channel of New York’s East River. It’s currently in its third phase of testing, which includes a commercial pilot scale build-out 27, 28, 29. This project will occupy an area of 21.6 acres and is going to be the world’s first grid-connected array of tidal turbines 30. New York has several good sources for generating tidal power, like the East River, St. Lawrence, and Niagara rivers. Overall the state has the potential to generate an estimated 500-1,000MW of power from kinetic energy 29.

While it is a clean, compact, and predictable power source, tidal has some shortcomings: it lacks thorough research, there are concerns about electromagnetic emissions impacting marine life, and the construction costs are still high 24. With all the projects going on right now, we should start getting some answers about the future viability of tidal technologies.

But it’s not just new methods of generation, we’re also seeing innovations for a core component of hydropower: the hydraulic turbines. Turbulent, a Belgium company, recently introduced their eco-friendly turbines for run-of-river applications. Turbulent’s vortex hydraulic turbines range in power from 5 to 70kW, and are a compact and low-noise submerged design for both on-grid and off-grid applications. Prefabricated parts are installed next to the water and then the excavated space is backfilled after the installation. The turbines have curved blades and operate under low RPM, so the low pressure in the turbine make it fish-friendly 31.

Turbulent implemented a project in Green School, the world-famous sustainable school located next to the Ayung river in Bali, Indonesia. The 13kW vortex Turbine has benefited more than seven hundred students, teachers and staff. The company has other big projects ongoing too, like a micro-hydro power plant in Taiwan that will provide 600kW of continuous power 32.

Another breakthrough for water-powered energy, developed by Waterotor, is a technology that converts over 50% of energy capacity from slow-moving water into electricity. Water that’s moving at about 5.5 mph can generate power at a cost of $0.05/kWh. At speeds of 4 mph or slower that price can get up to $0.15/kWh 33.

As we’ve seen in the last few decades, the world is transitioning to a low-carbon future where renewable resources supply a larger portion of our electricity needs. After providing electricity for more than a century in all parts of the globe, it’s not surprising that hydropower’s growth has been decreasing compared to the quick spread of other renewables. However, due to the intermittent nature of solar and wind, it’s impossible to ensure cost-efficient grid stability with those alone. So the old workhorse of hydropower is still essential for the transition to low-carbon, but we need to keep looking at newer technologies and approaches that can minimize the environmental impacts.

And to learn a lot more about those impacts, be sure to jump over to the YouTube channel Terra Mater to see more about that in their part of this collaboration. You’ll find a link in the description. You’ll learn a lot about some of the surprising downsides to hydropower and what it means for the areas affected. And it helps to give some context for why these newer technologies and research are so important to the future of hydropower.


  1. "A brief history of hydropower," International Hydropower Association ↩︎

  2. "Carbon Critical: Hydropower, the Old Renewable," 10 June 2020. ↩︎

  3. March 2020. ↩︎

  4. "Facts of Hydropower in the EU," 2018. ↩︎

  5. Killingtveit, "Hydropower," in Managing Global Warming, 2019, pp. 265-315. ↩︎

  6. "Electricity facts," Government of Canada. ↩︎

  7. P. M. M. L. S. Nasir El Bassam, "Hydropower," in Distributed Renewable Energies for Off-Grid Communities, Elsevier, 2013, pp. 167-174. ↩︎

  8. "Hydroelectric Power: How it Works," U.S. Geological Survey. ↩︎

  9. "Types of hydropower," Inernational Hydropower Association. ↩︎

  10. "Hydroelectric Energy," National Geographic. ↩︎

  11. "Conventional Hydroelectric Dams," Penn State University. ↩︎

  12. "What is run-of-river?." ↩︎

  13. "Pumped storage hydropower," International Hydropower Association. ↩︎

  14. F. T. D. J. D. R. J. L. C. S. M. B.-S. E. J. D. M. E. W. Samuel C. Johnson, "Selecting Favorable Energy Storage Technologies for Nuclear Power," in Storage and Hybridization of Nuclear Energy: Techno-economic Integration of Renewable and Nuclear Energy, 2019, pp. 119-175. ↩︎

  15. "Pumped-Storage Hydropower," Office of Energy Efficiency & Renewable Energy. ↩︎

  16. "Hydropower Status Report," International Hydropower Association, 2020. ↩︎

  17. "Sources of Energy: A Comparison." ↩︎

  18. "Greenhouse gas emissions," International Hydropower Association. ↩︎

  19. A. A. d. M. M. Marla T. B. Geller, "Life Cycle Assessment of a Small Hydropower Plant in the Brazilian Amazon," Journal of Sustainable Development of Energy, Water Journal of Sustainable Development of Energy, Water, vol. 4, no. 4, pp. 379-391, 2016. ↩︎

  20. "Levelized Cost and Levelized Avoided Cost of New Generation Resources in the Annual Energy Outlook 2020," February 2020 ↩︎

  21. "10 Reasons for promoting the hydroelectricity," Itaipu. ↩︎

  22. "Benefits of Hydropower," Office of Energy Efficiency & Renewable Energy. ↩︎

  23. "Hydropower or Solar Power?," Green Journal, 4 December 2017. ↩︎

  24. "Riding the renewable wave: tidal energy advantages and disadvantages," 26 June 2020. ↩︎

  25. "Tidal Stream Projects – MayGen." ↩︎

  26. "Tidal Stream Projects – Strangford Narrows." ↩︎

  27. "Roosevelt Island Tidal Energy Project, New York," PowerTechnology. ↩︎

  28. "The East River Becomes a New Energy Source for New York City," The Wall Street Journal, 15 September 2020. ↩︎

  29. "Roosevelt Island Tidal Energy Project (RITE), East River, New York," Renewable Technology. ↩︎

  30. "The RITE Project (East River, NYC)." ↩︎

  31. "Downloads," Turbulent. ↩︎

  32. "Projects," Turbulent. ↩︎

  33. Waterotor Energy Technology. ↩︎

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