AsianScientist (Jun. 29, 2015) – In its 2012 report on renewable energy, the Intergovernmental Panel for Climate Change (IPCC) listed hydropower as one of the six major renewable energy sources, alongside bioenergy, solar, geothermal, ocean and wind.
Hydropower, as its name suggests, harnesses the potential energy from water flowing from a higher to a lower elevation to generate electricity. Humans have used water this way for more than a thousand years, beginning with farmers using water mills for grinding wheat and sawing wood.
We have come a long way since the first hydroelectric station powered up in 1882—today hydropower provides 16.4 percent of the world’s electricity, according to a report by the Center of Climate and Energy Solutions, a non-profit organization based in the United States.
But while it is less polluting than smokestack industries and less dangerous than nuclear energy, hydropower is not entirely impact-free, as it involves massive construction projects and potentially devastating downstream effects.
Take for example China, currently the world leader in hydropower production, with 61.4 Mtoe (million tons of oil equivalent) each year. Despite its considerable hydropower capabilities, China ranks poorly on the World Energy Council’s Energy Trilemma index (74th out of 129), a ranking that takes into account the ability of a country to balance energy security, equity and environmental sustainability.
The area surrounding the Three Gorges Dam, a massive hydroelectric dam spanning the Yangtze River in China’s Hubei province, has reportedly had a 70 percent increase in natural disasters since the completion of the dam in 2010. Alteration to the water flow also increases the probability of landslides and flooding occurring—hydrologists warn that damming could lower water table levels, which may exacerbate the situation in the event of a drought.
Disrupting the ‘mother of water’
After scaling up its hydropower goals to 430 GW (from 380 GW) by 2020, China is now looking to invest in dam construction on the Mekong River. The Mekong River is derived from a Laotian-Thai phrase ‘Mae Nam Khong’ which translates to ‘mother of water,’ symbolizing the life it brings to the people that share its resources. The longest river in Southeast Asia, the Mekong River is shared by six nations. China and Laos each have 2,000 kilometers of the Mekong running through their respective borders.
In 1995, the Mekong Treaty was signed by four countries of the Lower Mekong—Laos, Cambodia, Thailand and Vietnam—to promote cooperation and mutually-beneficial development of the Mekong River Basin. However, Laos and Thailand caused a shake-up in 2012 by starting the US$3.8 billion construction of the Xayaburi Dam.
Once completed, the Xayaburi Dam will be an ecological game-changer for the entire region as changes in sediment and nutrient flow are predicted to severely affect agriculture downstream in Cambodia all way down to the Mekong Delta in Vietnam. Annual flooding patterns will also likely be affected, disrupting the complex fish migration routes of hundreds of species.
Unlike rivers in Canada where fish passes and ladders allow fish to head upstream to spawn, such projects have been unsuccessful on the Mekong to date, says Ian Baird, an assistant professor of geography at the University of Wisconsin-Madison who studies the Xayaburi Dam development and its impacts.
“Rather than just needing to create conditions for just a single or a few species to pass a dam… there are well over a hundred migrating species that need to be accommodated in the Mekong region,” Baird explained to Asian Scientist Magazine. “And these fish migrate in different seasons, and in different parts of the water column.”
People are not spared from a loss of habitat either. An estimated 40-80 million people have been displaced by dams in India and China alone.
Decentralization, smaller dams, or no dams at all?
To minimize widespread ecological damage, one suggestion advocated by non-governmental organizations such as the International Rivers and Conservation Watch is the decentralization of hydropower plants. For example, the planned capacity of the Xayaburi Dam is approximately 1,300 MW and will be able to power one million households. However, most of these households will be in cities far away, while the villages near the dam, if not already flooded or its inhabitants resettled, will continue to have little or no access to electricity.
Microdams, also known as run-of-river dams, do not require extensive construction and as such, will not as drastically affect the river basin hydrology and fish stocks. Small scale hydropower dams would also help alleviate poverty by providing energy for the inhabitants on the Mekong. The downside to microdams is that the energy generated depends on seasonal flow and therefore may not provide the energy security that governments strive for.
Or what if dams could be eliminated entirely? A practice called pumped hydro uses electricity generated by other power sources like solar, nuclear and wind to lift water uphill to a reservoir, where it is stored as potential energy for later use. When the power is needed, the water is allowed to rush downhill, turning a turbine and generating electricity.
But as Baird cautions, newer technologies must first be “well-tested and proven before too much confidence is put in it.” And it remains to be seen if we can harness this infinite, renewable source of energy in a responsible manner, scaling up to meet our energy demands while also protecting the sanctity of the ‘water mother.’
This article was first published in the print version of Asian Scientist Magazine, July 2015.
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