Hydropower?

Hello everyone! 

Welcome to my first post of 2015. I hope you're all set for a great year! :)

I came across this narrated animation on YouTube explaining how hydropower works. It's a pretty simple concept.

According to the World Energy Council (2010), hydropower is a important global energy resource and in ~160 countries, hydropower contribute significantly to national energy mixes.  

Advantages (adapted from Kaunda et al, 2012):

- Based on the hydrological cycle and therefore considered as a renewable energy resource. 

- Compared to other electricity generation technologies, levels of GHG emission from hydropower are relatively low. The life cycle GHG emission factors for hydropower technologies are ~15–25 g CO2 equivalent per kWhel (Although these figures vary according to the type of reservoir and manufacturing process). Fossil-fuel power generation technologies range between 600–1200 g CO2 equivalent per kWhel (Lenzen, 2008)

- Immerse energy potential, especially in developing countries.  

- Small-scale projects are more manageable and fewer environmental/social impacts. However, electricity generation is low. 

Disadvantages (mainly resulting from large-scale projects) (adapted from Kaunda et al, 2012):

- Social and environmental impacts during construction and operation phases of large-scale projects e.g. building of roads, dam, weirs, tunnels, power plants structures, and electricity transmission lines.

- Land clearance and some human settlements displaced. 

- Inundation of land by the reservoir may destroy ecosystem, destroy infrastructure, and displace settlements. 

- Localised air and water pollution, loss in biodiversity, destruction of infrastructure, change of landscape, destruction of settlements, and loss of livelihood and cultural identity in the direct project affected areas. 

- Large-scale storage hydropower stations: emission of some greenhouse gases (GHGs), especially methane (CH4) and carbon dioxide (CO2) as a result of the buried organic matter decomposition in the absence of enough oxygen (Howarth et al, 2011). 

- Hydrological changes to the river system. 

- Economic, social and environmental challenges. 

Three Gorges Dam, China

A recent news article by AFP (2015) claimed that the Three Gorges Dam in China has broken the world record for annual hydroelectric power production (Yangtze river power station generated 98.8 billion kilowatt hours of electricity in 2014). The dam boasts an installed capacity of 22,500 MW and claimed that it prevented 100 million tons of carbon emissions in 2014. I would like to question where this figure came from and at what level the baseline was set to calculate the emissions reduction.  

The dam has been under intense scrutiny for more than a decade, since it was unveiled in 1994. There are environmental and social controversies surrounding the dam. Some studies suggest effects to the Yangtze River flow (Guo et al, 2012), including sedimentary and geomorphic impacts (Yang et al, 2014). There have also been effects to biodiversity and ecosystems (Guo et al, 2012), especially declining dolphin populations (Araujo and Wang, 2015). 

The Three Gorges Dam - Before and After
http://www1.american.edu/ted/ICE/china-dam-impact.html

Final Remarks:

Hydropower is an efficient and mature technology choice, but small-scale projects seem more feasible. Large-scale projects enable lots of energy to be produced, but there are some negative environmental and social impacts to be considered. In some countries such as Vietnam, hydropower is nearing capacity and there have been suggestions that hydropower plants will be developed almost of potential by 2015-2016 (Pham and Tran, 2013).  Therefore, alternatives should be sought. 

Araújo, C. C., & Wang, J. Y. (2015). The dammed river dolphins of Brazil: impacts and conservation. Oryx, 49(01), 17-24.

Guo, L., Hu, C., & Zhang, L. (2012, October). Ecosystem and biodiversity impacts of Three Gorges Dam. In Geomatics for Integrated Water Resources Management (GIWRM), 2012 International Symposium on (pp. 1-4). IEEE.

Guo, H., Hu, Q., Zhang, Q., & Feng, S. (2012). Effects of the three gorges dam on Yangtze river flow and river interaction with Poyang Lake, China: 2003–2008. Journal of Hydrology, 416, 19-27.

Howarth, R. Santoro, and A. Ingraffea, “Methane and the greenhouse-gas footprint of natural gas from shale formations,” Journal of Climatic Change, vol. 106, no. 4, pp. 679–690, 2011.

Lenzen, “Life cycle energy and greenhouse gas emissions of nuclear energy: a review,” Energy Conversion and Management, vol. 49, no. 8, pp. 2178–2199, 2008.

World Energy Council, Survey of Energy Resources: Hydropower, World Energy Council, 2010.

Yang, S. L., Milliman, J. D., Xu, K. H., Deng, B., Zhang, X. Y., & Luo, X. X. (2014). Downstream sedimentary and geomorphic impacts of the Three Gorges Dam on the Yangtze River. Earth-Science Reviews, 138, 469-486.