Can Hydropower Be Used Everywhere?

Hydropower is a renewable form of energy that utilizes the natural flow of water to generate electricity. It works by using the force of flowing or falling water to spin large turbines connected to generators, which convert the mechanical energy into electrical energy (DOE, 2022). The key benefits of hydropower include its low operating costs, clean emissions-free energy, grid reliability, and water management capabilities like flood control and irrigation.

The goal of this content is to determine where hydropower can and can’t be utilized based on geographic, environmental, social, political, economic, and technological factors. By examining the requirements and limitations of hydropower technology, we can gain a deeper understanding of its potentials and constraints for electricity generation worldwide.

Hydropower Basics

There are three main types of hydropower facilities:

• Impoundment – Water is stored behind a dam and then released through turbines in the dam to generate electricity [1]. This allows electricity to be generated on demand when needed. Examples are large-scale reservoirs and dam systems.
• Diversion – Channels water from a river through a canal or penstock to turn turbines located off the main waterway. Diversion systems generate power while allowing water to keep flowing [2]. These are considered ‘run-of-river’ systems.
• Pumped storage – Stores energy by pumping water uphill to a reservoir at higher elevation. During peaks in electricity demand, water is released back downhill through turbines [3]. Considered a type of large-scale energy storage.

Impoundment facilities like dams offer storage and control over electricity output. Diversion and ‘run-of-river’ systems generate power from natural water flow with little to no storage. Pumped storage recycles water between reservoirs to store power.

Geographic Requirements

Hydropower requires the right geographic features in order to harness the energy from flowing water. The most essential requirements are having a flowing water source such as a river or tidal site, and an elevation change to allow the water to fall. The amount of precipitation that drains into rivers and streams in a geographic area determines the amount of water available for producing hydropower (https://www.eia.gov/energyexplained/hydropower/). In his 1924 paper, R. Blanchard analyzed the geographic factors needed for developing hydropower, emphasizing the importance of an ample and reliable water supply combined with topography allowing for dams and reservoirs (https://www.jstor.org/stable/208357).

Hydropower facilities need a certain amount of land area depending on the scale of the project and type of generation. Using data from hydropower plants across the U.S., one estimate is that on average it takes 0.265 acres of land to generate a megawatt hour of electricity from hydropower, but this can vary significantly by site (https://www.freeingenergy.com/math/hydro-land-acres-hectares-miles-m124/). Overall, the key geographic factors enabling hydropower development are abundant water resources, elevation change, and adequate land area.

Environmental Concerns

Hydropower dams and reservoirs can have significant environmental impacts, especially on wildlife habitats and fish migration patterns. Large dams block fish migration routes and prevent access to spawning grounds upstream, disrupting the life cycles of migratory fish like salmon (Smithsonian Magazine, 2022). Dams also change natural water flows, which alters habitat conditions downstream. Less water flowing downstream can negatively impact water quality, increase water temperature, and reduce oxygen levels.

According to the U.S. Geological Survey, the changes to water flow “have contributed to the decline of some fish species…by slowing the rate at which nutrients and biota are flushed from the system” (Valuing the Water Environment, 2022). Reduced river flows diminish suitable habitat for bottom-dwelling species. Reservoirs created by dams can also flood terrestrial ecosystems and disrupt plant and animal communities.

While fish ladders and other solutions have been implemented, their effectiveness is debated. Overall, large hydropower projects significantly modify river ecosystems and aquatic life (Grubb, 2019). Smaller run-of-river projects have less impact, but all dams obstruct natural water flows to some degree.

Sources:

Valuing the Water Environment. U.S. Geological Survey, 2022, pubs.usgs.gov/of/2004/1001/pdf/ofr2004-1001.pdf. Accessed 24 Feb 2023.

Grubb, Jeff. “Why Some Hydropower Plants Are Worse for the Climate Than Coal.” Grist, 14 Nov. 2019, grist.org/article/why-some-hydropower-plants-are-worse-for-the-climate-than-coal/. Accessed 24 Feb 2023.

“How Dams Damage Rivers.” Smithsonian Magazine, 1 Aug. 2022, www.smithsonianmag.com/science-nature/how-dams-damage-rivers-180978739/. Accessed 24 Feb 2023.

Social & Political Factors

Hydropower projects often lead to social and political concerns, especially around population displacement and resettlement. Large dams can flood inhabited valleys, forcing people to relocate against their will. This occurred with China’s Three Gorges Dam, which displaced over 1 million people. Resettlement is traumatic and disruptive for communities.

There are also competing water uses that lead to political debates. Hydropower dams control the flow of rivers, which can reduce water access for drinking, irrigation, and transportation downstream. This requires negotiations between countries that share rivers, like Egypt and Ethiopia over the Nile River.

Extensive regulation and permitting processes are often required for hydropower projects. Projects must comply with environmental protection laws and obtain construction permits. There is sometimes local opposition and protests against proposed dams. Overall, hydropower has major social and political considerations beyond pure technical feasibility.

Sources:

https://slideplayer.com/slide/6186362/

https://www.slideserve.com/zaina/hydropower-i

Economic Viability

Hydropower plants require substantial upfront investments to construct dams, tunnels, turbines and other infrastructure. According to the National Hydropower Association’s strategic plan, hydropower’s high capital costs make it difficult to attract private investments and secure financing (https://www.hydro.org/wp-content/uploads/2017/08/Strategic-Plan-Documents.pdf). However, hydropower delivers very low operating and maintenance costs over the long run. The U.S. Department of Energy notes that once a facility is constructed, hydropower is extremely cost-effective compared to other energy sources (https://hydropowervision.pnnl.gov/about/state-of-hydropower). The average hydropower plant has operating costs between $0.01 – $0.03 per kWh, lower than fossil fuels, nuclear, solar, or wind. While the initial investment is high, over time hydropower can deliver very affordable renewable energy.

Technological Advances

Recent innovations have made hydropower feasible in locations that previously were not viable sites. New turbine and generator designs now allow efficient energy generation at low-head sites, where the water drop is less than 5 meters. Micro hydropower plants with outputs under 100 kW and pico plants under 5 kW can operate in small rivers or streams.

Advances in modular and customizable turbine designs from companies like Voith Hydro and Andritz Hydro enable optimized performance for each unique site. Variable speed generators provide more flexibility to match fluctuating flows. New materials like carbon fiber composites reduce costs. Automation and remote monitoring improve operability. Overall, these innovations expand hydropower’s range to locations previously unsuitable.

Micro & Pico Hydropower

Smaller hydropower systems called micro and pico hydropower provide decentralized options for providing electricity in remote areas. Micro hydropower systems have capacities up to 100 kW, while pico hydropower systems are less than 5 kW. These small systems have lower barriers to implementation compared to large hydropower dams and often have reduced environmental and social impact.

For example, a report from the World Bank found that decentralized micro hydropower projects in Nepal provided clean energy access to remote mountain communities more affordably than expanding the centralized grid. The smaller scale and distributed nature of micro and pico projects enables providing electricity to rural populations that would otherwise lack access. (Source)

Micro and pico hydropower can utilize small rivers, streams, irrigation canals, and even pipelines to generate electricity locally using small run-of-river or diversion projects. This provides an alternative to transporting electricity over long distances when serving small, distributed loads. While micro and pico projects still require viable hydro resources, they can be implemented in more locations than large-scale hydropower.

Limitations Summary

While hydropower can provide clean, renewable electricity in many parts of the world, there are several key limitations restricting further growth of this energy source globally. These limitations relate to geographic, environmental, social, political, and economic factors.

Geographically, hydropower requires specific terrain and water flow conditions to be viable, which rules out large portions of the world’s land area. Building dams and reservoirs is only feasible in certain mountainous regions and river systems [1]. This geographic restriction inherently limits how much global energy demand can be met by hydropower.

Environmentally, dams and reservoirs can significantly disrupt local ecosystems and wildlife habitats. Blocking rivers alters water flows, temperatures, sediment patterns and fish migration routes [2]. Large reservoirs also flood areas and produce methane emissions. These effects make building new hydropower dams controversial in many locations.

Socially and politically, new hydropower projects often face resistance from local communities displaced or impacted by reservoir flooding and changing river dynamics. Governments may lack incentives to invest in hydropower versus other energy sources as well. These social and political barriers hinder hydropower growth in some regions.

Economically, hydropower has high upfront capital costs for dam and turbine construction. Long-term revenue uncertainty, evolving electricity market dynamics, and competition from other renewables like solar and wind can make hydropower less financially attractive. This restricts private investment in new hydropower facilities.

While a valuable renewable electricity source in suitable locations, hydropower faces geographic, environmental, social, political, and economic limitations to large-scale global expansion.

Conclusion

In summary, there are several key factors that determine the viability of hydropower in a given location:

– Geographic requirements – Areas with access to flowing water and suitable topology are best suited for hydropower. Hilly or mountainous regions near rivers provide the elevation change needed to generate electricity.

– Environmental concerns – Hydropower dams and generators can impact wildlife habitats and ecosystems. Projects must assess and mitigate environmental damage.

– Social & political factors – Community support and government regulations enable or restrict projects. There is often debate over dams given displacement and cultural impacts.

– Economic viability – Upfront infrastructure costs are high. Sites with good energy output potential deliver better return on investment.

– Technology advances – New lower-cost and low-impact options like micro/pico hydropower and in-stream turbines are expanding opportunities.

When available resources and conditions allow, hydropower can play an important role in renewable energy portfolios. It provides stable base load power to supplement variable solar and wind. With thoughtful design and mitigation of downsides, hydropower can be part of building sustainable energy systems.