Hydroelectricity is a power-generation technology that is produced when water rotates a turbine shaft. That movement is then converted into electricity with the use of an electrical generator. About 20% of the world’s electricity production is currently derived from hydroelectricity.
The four largest electricity-producing stations in the world are all based on hydroelectricity technologies, located in China, Venezuela, and Brazil. In Australia, there are more than 100 hydroelectricity stations in operation.
In the United States, just 6% of total electricity is produced through hydroelectricity, though it does make up 35% of renewable electricity that is generated.
Here are the pros and cons of hydroelectricity to think about and discuss.
List of the Pros of Hydroelectricity
1. It reduces our overall consumption of fossil fuels.
Hydroelectricity is based on water movement. Outside of the fossil fuels that are consumed to create the infrastructure and delivery networks for the electricity, none are consumed to create the energy itself. Except for the water, there is no fuel involved. That means, over time, we can create net gains to the emissions that are released into our atmosphere if all electricity could be converted over to hydroelectricity over time.
2. The energy costs of hydroelectricity are lower than any other common form of energy.
In the United States, most hydropower stations are located in Oregon, Washington State, and Idaho. Residents of these three states typically see lower power costs each month because hydroelectricity is extremely cheap. The average cost of hydroelectricity is just $0.02 per kilowatt hour (KWH). Even geothermal energy is at $0.03 per KWH. Coal power is priced at $0.075 per KWH, while nuclear is $0.095 per KWH.
3. There are lower ongoing maintenance costs associated with hydroelectricity.
Hydroelectricity is a very reliable source of energy. It requires little ongoing maintenance compared to other forms of energy, such as nuclear. The fuel costs for hydroelectricity are minimal, if they even exist at all. If a community is able to afford the initial capital expenditures required to install hydropower, then they will experience cost savings immediately. Over time, that means they’ll pay less for the power they need.
4. Hydroelectricity is incredibly reliable.
Hydroelectricity is also one of the most stable forms of electricity that we currently distribute to homes and businesses around the world. There are few fluctuations in the amount of power that is being produced. Hydropower is also scalable to meet the changing demands of a community. That is why it is a highly desired baseload energy resource. Efficiency rates for hydroelectricity commonly exceed 90%.
5. New productions levels can be added to existing resources.
Although hydroelectricity is a minimal component of the U.S. power grid, several nations receive more than 90% of their electricity through this resource. New production levels can be added to existing facilities as well, extending the life and reach of the resource. The average hydroelectricity facility could have its total maximum output expanded by up to 20% with simple upgrades.
6. It is a renewable power source.
Because hydroelectricity is based on the natural water cycle of our planet, which is powered by the sun, it is considered a renewable source of power. That makes it a more reliable long-term source of energy compared to finite fossil fuels. Although this technology can be susceptible to long-term weather pattern changes, such as an extended drought, careful placement can limit these risks, allowing each community to benefit from this affordable type of power.
7. Reservoirs create new recreational opportunities.
The reservoirs created behind large-scale hydroelectricity facilities create a number of recreational and entrepreneurial opportunities for the local community. Boating, fishing, and swimming are commonly available. Most installations, as part of the placement agreement, require the public to have access to the reservoir for such activities. That means you don’t need to live by a lake or an ocean to have a nice day at the beach.
8. They can change output levels extremely quickly.
Hydroelectricity facilities have the ability to quickly change output levels, depending upon the demand placed upon the network at any given time. They can literally go from zero power generation to maximum output almost immediately. That means they can be a much-needed backup for the local power grid if something should happen to the primary electricity generation facility.
9. It creates new agricultural opportunities.
The reservoir created by the hydroelectricity facility can provide new agricultural opportunities for the region as well. Dams on the Nile River, for example, helped to control the annual floods that occurred. The reservoir can be a water source for field irrigation. The reservoir can even be used as a community water supply, if filtering infrastructure is part of the water distribution network. When combined with the recreational opportunities, the net economic gains can help to offset the higher capital costs of this type of power generation.
10. It is a domestic source of power.
All countries that develop hydroelectricity are able to create domestic resources with their facilities. That helps to limit import costs for power, especially for border communities. It even creates opportunities for exporting electricity. Global exports of electricity in 2016 were valued at $26.4 billion, with Germany topping the list of exporters by accounting for 11.5% of the total market. The United States imports about 50 million MWH of electricity annually, while exports have declined to under 9 million MWH.
List of the Cons of Hydroelectricity
1. It changes the landscape.
Hydroelectricity requires high volumes of water movement to be effective. That means we construct dams and other structures along rivers to provide the infrastructure required to benefit from water movement. That changes how water flows and builds a reservoir behind the dam that alters habitat structures. When power lines and road networks are included, the region is very different from its natural state.
2. It can affect marine life negatively.
We also know that dams can negatively impact marine life in multiple ways. Salmon may not be able to swim upstream for their spawning process. Water flow changes may alter how fish develop or where they develop. Other biological and physical factors are involved, along with species exploitation by new fishing and recreation opportunities in the newly created reservoir. Unless specific steps are taken, like the inclusion of salmon ladders, the benefits of hydroelectricity may be outweighed by the negatives it creates.
3. It is expensive to build new hydroelectricity facilities.
The construction of any power plant is a prohibitive capital cost for many communities. According to the Global CCS Institute, the cost of a new facility is up to $8,000 per kilowatt. Although maintenance costs are typically lower for this type of electricity generation, the installation costs for hydroelectricity to produce the expected 60 trillion KWH required by 2050 would be $3 trillion in just the United States.
4. It is susceptible to long-term weather patterns.
Hydroelectricity may be a reliable form of power when water is present. When there is no water, however, then there is no electricity being produced. An extended drought or change in weather patterns, such as a reduced snowpack, can immediately impact the amount of power that can be generated by a facility. In California, the drought from 2011-2015 caused hydropower levels to drop from meeting 18% of total needs to less than 7% of total needs.
5. There are a finite number of locations suitable for hydroelectricity.
There are only a handful of areas on our planet that are suitable for large-scale hydroelectricity installations. We have already used many of the areas, which limits the amount of expansion that is available. About 30 hydroelectricity facilities currently produce more than 2,000 megawatts of energy, but only one of these projects is a new facility that was started in the past 24 months.
6. There are limits on long-term capacities.
Hydroelectricity is dependent upon the size of the facility constructed and the water flow available from the local waterway. That means the total capacity is limited once it is installed. Greater efficiencies may be able to produce more power from existing equipment, but there is no way to have large increases in demand be met. Most facilities are built on rivers, so the pattern of power generation is completely dependent upon the pattern of water flows that are available.
7. Water oxygen levels can be altered with hydroelectricity.
Hydropower facilities are known to impact the quality of the water passing through. One of the greatest concerns is a lower level of dissolved oxygen levels within the water. This issue can be extremely harmful to riverbank habitats, requiring artificial aeration below the facility to reduce its impact. When combined with lower downstream water flows, if not properly managed, an entire eco-system could be destroyed by one facility.
These hydroelectricity pros and cons show us that this renewable energy resource can provide stable, affordable energy to homes and businesses around the world. There are installation costs and challenges which must be overcome, which means it is not a short-term solution. Hydroelectricity is a long-term installation that invests into our future.