This House would build hydroelectric dams

Dams have probably existed for about as long as humans have had agriculture, to control water flow and to use the hydraulic energy for a water mill. Since the 19th century, dams have also been used to convert the hydraulic energy into electricity. There are several methods, but they all rely on the dam (in jargon called a hydroelectric power station) converting the energy of flowing water into electricity through a turbine and generator.

There are all sizes of hydroelectric power stations, varying from ‘pico hydro’, which is usually just a few pipes diverting water from a river instead of a dam, to large and specialized industrial facilities. The large dams generate a lot of energy but have also drawn a lot of criticism because they involve large-scale landscape restructuring. This casefile takes a closer look into that debate, and ignores issues that might come into play around the smaller scale hydroelectric power stations.

The largest hydroelectric power stations in operation as of 2011 are the Three Gorges Dam in China, Itaipu, shared by Brazil and Paraguay, Huri in Venezuela, Tcuruí in Brazil and the Grand Coulee in the United States.[1] Power from hydroelectric power stations in 2008 was about 15% of total power production and is by far the largest renewable energy source in use, providing between 80% - 85% of total renewable energy production.[2]

 

Title 
Hydro electric dams reduce carbon dioxide emissions
Point 

Hydroelectric dams burn no fossil fuels so emit no greenhouse gasses at all in producing energy. Suppose we replace all coal fired power stations with hydroelectric power stations. In 2010, over 42% of global electricity production was produced through coal, accounting for over 28% of global carbon dioxide emissions.[1] Since there is more than enough potential capacity for hydropower,[2] we could hypothetically completely replace coal and even other fossil fuels for electricity, thus helping cut down greenhouse gas emissions massively.

[1] IEA, Power generation from coal, 2010

[2] Energy Consumers Edge. Hydropower dams pros and cons.

Counterpoint 

Hydroelectric dams don’t reduce carbon dioxide emissions. Dams currently hold off about 15% of global freshwater runoff. If we want to sustain biodiversity and river-related goods and services, we can’t easily increase the number of dams.[1] Also: building dams requires cutting down forests, which themselves are important tools in combating greenhouse gases, since they consume and ‘lock up’ carbon dioxide. Plus, the construction of the dams themselves releases carbon dioxide. Finally: global energy demand is expected to continue increasing,[2] meaning that hydropower will probably just be added to the supply and not replace coal.

[1] International Rivers, Frequently Asked Questions.

[2] IEA, World Energy Outlook, 2010, Executive summary

Title 
Hydroelectric dams provide cheap access to renewable energy
Point 

In 2010, about 1.4 billion people had no access to electricity.[1] Hydropower provides a source of energy that is cheaper even than conventional coal.[2] Large dams can last for over a hundred years[3] and are easy to switch on and off according to demand, making them very cost-effective. Given that having no access to electricity makes work and study nearly impossible, alleviating global poverty by giving access to electricity is an important step to take.

[1] IEA, Access to Electricity, 2010

[2] Wikipedia. Cost of electricity by source.

[3] WWF, Dam Right!, 2003

Counterpoint 

Hydroelectric dams require massive initial investments. True, dams generate cheap electricity, when the dams are eventually built. But building dams is incredibly costly. Actual costs for hydropower dams are almost always far higher than estimated; in a number of cases, the actual cost was more than double the estimated cost. The Itaipu Dam in South America cost $20 billion and took 18 years to build. This was 488% higher than originally estimated.[1] Given that there are cheaper alternatives than large-scale dams for renewable and accessible energy, dams aren’t worth it from an economic perspective.

[1] International Rivers, Frequently Asked Questions.

Title 
Hydroelectric dams can be used to provide flood control and irrigation
Point 

The large water reservoirs created by hydroelectric dams can provide facilities for water sports and can become tourist attractions themselves. The reservoirs can be used for irrigation to help farmers and can be a means for flood control. A prime example of this is the Tennessee Valley Authority, an organisation responsible for flood control, electricity generation, economic development and even fertilizer generation in the Tennessee Valley in the U.S., spanning parts of Alabama, Mississippi, Kentucky, Georgia, North Carolina and Virginia.[1]

[1] Tennessee Valley Authority, homepage.

Counterpoint 

As well as benefits hydroelectric dams have added dangers. Dams increase the risk of earthquakes, because the weight of the water-reservoir impacts the Earth’s crust underneath.[1] Moreover, big dams run the risk of bursting, causing massive damage in their wake. The bursting of the Chinese Banqiao dam in 1975 is estimated to have cost about 230,000 lives.[2]

[1] BBC News, ‘Earthquake risk from dams’, 2002

[2] The New Internationalist, ‘Big dams, big trouble’, 2003

Title 
Hydroelectric dams increase methane emissions
Point 

Hydroelectric dams emit a lot of methane, which is an even more potent greenhouse gas then carbon dioxide. This happens when the plants and vegetation submerged in the reservoir start to rot under water: they then produce methane which bubbles up and is released into the atmosphere. On balance, some dams produce more greenhouse gasses than conventional power plants running on fossil fuel.[1]

[1] New Scientist, ‘Hydroelectric power's dirty secret revealed’, 2005

Counterpoint 

Hydroelectric dams can mitigate methane emissions. Dams can capture the methane released from their reservoir and even use it to their benefit: an experimental project in Brazil showed that hydroelectric dams can capture the methane and burn it to produce even more energy, whilst at the same time preventing the methane from being released.[1]

[1] BBC News, Earthquake risk from dams, 2002

Title 
Hydro electric dams destroy existing ecosystems
Point 

Large dams wreak havoc with the environment: they destroy habitats and ecosystems both further upstream and downstream. They prevent salmon from swimming upstream to spawn. The water going through them is often warmer and devoid of nutrients, depriving downstream riverine wildlife of their natural habitat. A shocking example is China’s Three Gorges Dam, which Scientific American called ‘an environmental disaster’.[1]

[1] Scientific American, ‘China’s Three Gorges Dam: An environmental disaster?’ 2008

Counterpoint 

Hydroelectric dams can mitigate the ecological impact. Hydroelectric dams can take steps to mitigate their environmental impact. For example, for salmon, dams these days have ‘fish ladders’, allowing them to reach their spawning grounds. For these and other sustainability measures, the International Hydropower Association developed several guidelines and protocols to minimize ecological impact as far as possible.[1]

[1] International Hydropower Association, Hydropower Sustainability Assessment Protocol.

Title 
Hydroelectric dams destroy communities
Point 

What applies to the environment, also applies to the human communities. Building dams often involves relocating people and removing them from their ancestral homelands. For example, China’s Three Gorges Dam involved relocating 1.3 million people,[1] involved severe human rights abuses[2] and has had dire social consequences.[3]

[1] CBS News, ‘China Completes Three Gorges Dam’, 2009

[2] International Rivers, Human Rights dammed of at Three Gorges, 2003

[3] New York Times, ‘Chinese Dam Projects Criticized for Their Human Costs’, 2007

Counterpoint 

Hydroelectric dams don’t destroy communities, governments do. Building dams only violates human rights if the governments building them do so. That’s why we never heard of large-scale human rights violations when the Hoover Dam in the United States was built. Moreover, responsible dam builders in the International Hydropower Association have taken steps to ensure they build dams with the utmost respect for human rights, through the guidelines mentioned above.

Bibliography 

BBC, ‘Earthquake risk from dams’, May 9, 2002. URL: http://news.bbc.co.uk/2/hi/science/nature/1974736.stm Last consulted: September 25, 2011

BBC, ‘Project aims to extract dam methane’, May 10, 2007. URL: http://news.bbc.co.uk/2/hi/6638705.stm  Last consulted: September 25, 2011

CBS News, ‘China Completes Three Gorges Dam’, February 11, 2009. URL: http://www.cbsnews.com/stories/2006/05/20/world/main1638180.shtml Last consulted: September 25, 2011.

International Energy Agency. Power generation from coal. 2010. URL for PDF: http://www.iea.org/papers/2010/power_generation_from_coal.pdf Last consulted: September 25, 2011

International Energy Agency. World Energy Outlook 2010. Executive Summary. 2010. URL for PDF: http://www.iea.org/weo/docs/weo2010/WEO2010_ES_English.pdf Last Consulted: September 25, 2011.

International Energy Agency. Access to Electricity. 2010. URL: http://www.iea.org/weo/electricity.asp  Last consulted: September 25, 2011.

Energy Consumers Edge. Hydropower dams pros and cons. Undated. URL: http://www.energy-consumers-edge.com/hydropower_dams_pros_and_cons.html  Last consulted: September 25, 2011

International Rivers. Frequently Asked Questions. Undated. URL: http://www.internationalrivers.org/en/node/480  Last consulted: September 25, 2011

International Rivers, Human Rights dammed of at Three Gorges. January 1, 2003. URL: http://www.internationalrivers.org/china/three-gorges-dam/human-rights-dammed-three-gorges Last consulted: September 25, 2011.

International Hydropower Association, Hydropower Sustainability Assessment Protocol. Undated. URL: http://hydrosustainability.org/  Last consulted: September 25, 2011.

New Scientist, ‘Hydroelectric power's dirty secret revealed’, February 24, 2005. URL: http://www.newscientist.com/article/dn7046-hydroelectric-powers-dirty-secret-revealed.html  Last consulted: September 25, 2011

New York Times, ‘Chinese Dam Projects Criticized for Their Human Costs’, November 19, 2007. URL: http://www.nytimes.com/2007/11/19/world/asia/19dam.html?_r=1&oref=slogin Last consulted: September 25, 2011.

Renewable Energy Policy Network. Renewables 2010 Global Status Report. July 15, 2010. URL for PDF: http://www.ren21.net/Portals/97/documents/GSR/REN21_GSR_2010_full_revised%20Sept2010.pdf

Scientific American, ‘China’s Three Gorges Dam: An environmental disaster?’. March 25, 2008. URL: http://www.scientificamerican.com/article.cfm?id=chinas-three-gorges-dam-disaster Last consulted: September 25, 2008.

Tennessee Valley Authority, homepage. Undated. URL: http://www.tva.gov/index.htm Last Consulted: September 25, 2011.

The New Internationalist, ‘Big dams, big trouble’, march, 2003. URL: http://findarticles.com/p/articles/mi_m0JQP/is_2003_March/ai_99232389/  Last consulted: September 25, 2011

Wikipedia. List of largest hydroelectric power stations. URL: http://en.wikipedia.org/wiki/List_of_largest_hydroelectric_power_stations  Last consulted: 25 september 2011

Wikipedia. Cost of electricity by source. URL: http://en.wikipedia.org/wiki/Cost_of_electricity_by_source Last consulted: September 25, 2011

WWF International, Dam Right! WWF's Dams Initiative, March 2003, http://www.rivernet.org/general/docs/damrightwwfcampsummary.pdf

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