As defined by the International Commission on Large Dams (ICOLD), a “large dam” is at least 15 m tall or must carry at least 3 million cubic meters of water. The controversial Bakun Dam, located at Balui River, about 200 km from Bintulu town in Sarawak, easily meets these criteria of a large dam.
Once completed, Bakun Dam would be 205 m tall, making it the second tallest dam in the world outside China. After nearly 15 years (which included several delays), the Bakun dam is expected to be completed by the end of 2010 with a cost overrun of nearly RM2 billion (about one-quarter more than the initial expected cost).
The Bakun Dam would generate 2,400 MW of electricity. Initially, it was planned that 70% of that generated electricity would be delivered to Peninsular (West) Malaysia and the rest to East Malaysia. However, according to the blog by Dato’ Sri Peter Chin Kah Fui, the Minister of Energy, Green Technology and Water, all of Bakun’s generated electricity would remain in Sarawak for the development of the Sarawak Corridor of Renewable Energy (SCORE) to make Sarawak a developed state by 2020.
Large dams are a reflection of human vanity. They are icons of a country’s technological advancement, aspirations, and economic and scientific progress. For instance, India’s first Prime Mister, Pandit Jawaharlal Nehru viewed massive dams like Bhakra Dam in India as a symbol of “the nation’s will to march forward with strength, determination and courage”. Similarly, Egypt’s second President, Colonel Gamal Abdel Nasser, saw the Aswan Dam as Egypt’s modern-day pyramid and a symbol of the nation’s defiance of Western powers.
The book “Silenced rivers: The ecology and politics of large dams” by Patrick McCully exposes the myths on the usefulness of large dams. River damming is done primarily for two purposes: 1) to increase the storage of water, such as for irrigation, and 2) to increase the hydraulic head; that is, to raise the difference in height between the reservoir surface and the river downstream. It is this hydraulic head that drives the water turbines to generate electricity. The higher the hydraulic head (or the higher one builds a dam), the more power or electricity one could potentially obtain.
Patrick McCully discusses at length the consequences of river dams, in particular of large dams. Among them are as follows:
- Dams alter the biodiversity of the river and its surrounding habitat because of changes in the river flow volume and pattern, and water quality (such as water temperature, nutrient content, turbidity, dissolved gases, and concentration of minerals and heavy metals).
- Dams are often built without a long term study on the impact of river damming on the environment. Additionally, those who carry out the environmental impacts are also not from independent bodies (with nothing to lose or gain if their assessment points to severe detrimental damage to the environment). Instead, those who carry out such environmental assessments are often only engineers with very little training in environmental studies. Consequently, large dams are typically built based on biased and excessively optimistic projections.
- Cost overruns and long delays often occur in building large dams. Moreover, large dams often fail to deliver the promised amount of power in electricity, even years after dam completion. On average, as estimated by the World Bank, hydroelectric dams only provide about half their potential capability. The High Aswan Dam, for instance, could potentially provide about 18,500 GWh per year, but actual electricity generated was about 40% or 7,200 GWh per year. The Bakun Dam is projected to generate as much as 16,785 GWh per year or 80% of its potential, a figure considered to be unrealistically optimistic.
- Dams can be sources of diseases such as schistosomiasis (bilharzia) and mosquito-borne diseases such as malaria, yellow fever, dengue, and Japanese encephalitis. Dams help to spread such water-borne diseases because they create habitats in which insects, snails, and other animals that serve as vectors (carriers) for these diseases to thrive.
- Large dams can cause earthquakes most possibly by the stored water exerting excessive pressure on the micro cracks and fissures in the ground under or near the reservoir. Reservoir operations from more than 70 dams in the world have been linked to earth tremors. In India, for example, five out of nine earthquakes in the 1980s were believed to have been induced by reservoirs. Recently, the Zipingpu Dam in China is believed to have caused the May 12, 2008 earthquake which killed about 80,000 people. Stored water as high as 100 m is sufficient to trigger earthquakes.
- Large dams cause displacement of a large number of people, often indigenous people with little voice in the political arena. It is estimated that 30 to 60 million people (mostly those in China) have been displaced due to river dams. The Bakun Dam has resulted in the displacement of 15,000 people, mostly from the Kayan and Kenyah ethnic groups. Moreover, human resettlement often cause hardship after resettlement, with many of those displaced unable to find good or permanent jobs or them being unable to continue their agriculture or hunting activities as prior to their resettlement. The Bakun Dam population in the Sungai Asap Resettlement, for example, has dwindled rapidly because the displaced natives are unable to secure jobs after resettlement.
- In contrast to popular belief, hydroelectric is not a green technology or a source of renewable energy. Although hydroelectric does not involve the burning of fossil fuel (source of carbon dioxide, a greenhouse gas), hydroelectric is instead a source of other greenhouses gases, primarily methane. Methane is about 20 times more potent than carbon dioxide in causing global warming. When huge areas of forest are flooded, this water-logged condition increases the emission of methane gas from decaying vegetation. The warm, nutrient-rich, and severely oxygen-depleted water at the bottom of tropical river dams can create conditions for methane-producing bacteria which feed on decaying vegetations. Furthermore, studies from Brazil and Canada estimated that their hydroelectric dams can have an equal or even a larger impact on global warming than electricity generated from conventional coal-powered plants. However, depending on the conditions such as local climate and vegetation as well as the amount of area flooded and amount of water stored, hydroelectric dams may instead contribute to a lesser impact on global warming than coal- or gas-powered plants.
It is a myth that dams are an effective flood control. Although dams can help to minimize the risk of the periodic, normal floods, they can instead become the source for severe and extreme flooding damages. By confining the river to a straighter course, embankments increase the volume and speed of the river, which in turn increase its potential to cause larger damage downstream. Containing the river’s sediment load within its banks raises the river bed, which means embankments must be raised further to compensate for the higher river bed. Eventually, the river level will rise above the height of the surrounding plain, a recipe for a devastating damage of a flash-flood should the huge embankments break. The problem is hydroelectric dams suffer from two conflicting purposes: to generate electricity and to reduce flooding. The water level in hydroelectric dams are intentionally kept high to increase the power for electricity, but by keeping the water level high, this creates a greater risk of flood damage. To reduce flooding events, the water level in reservoir must be kept low, but this act reduces the power for electricity. So if you are a river dam operator, what would you do? The country needs electricity, so you keep the water level high.
Patrick McCully’s book is an excellent book about the myths, science, and consequences of large dams. Though this book was published in 1998 and updated in 2001, its message remains relevant even today.
The Bakun Dam is a socially and environmentally destructive way to meet Malaysia’s growing energy needs. Greater economic growth and greater push for wealth require increasingly more energy to drive these aspirations. Presently, Malaysia is self-sufficient in energy, but this is expected to end by 2015 (only five years away). After that, Malaysia must import energy and scour her land and seas for further sources of energy. But traditional sources of energy (that is, fossil-based energy) are detrimental to our climate. At the moment, hydroeletric dams contribute 18% of Malaysia’s electricity needs.
So if hydroelectric is a dirty word and if we want to divorce ourselves from it, with what could we replace hydroelectric for our electricity? More gas- and coal-powered plants? But those energies are dirty too. Furthermore, natural gas and oil are both running out in Malaysia. What about nuclear energy? Oh, that would be another contentious and much more heated issue than the Bakun Dam controversy. Biofuel? Even if Malaysia’s palm oil biofuel is shown, without a shadow of doubt, to be net carbon zero, there’s not enough of palm oil to be a major supplier of energy for the country. Wind energy? No, Malaysia experiences only low wind speeds. Our best bet for renewable energies are solar and geothermal power, with some contribution from biogas and biofuel (provided they are shown to environmentally friendly). And nuclear power should also not be ruled out.
Issues like Bakun Dam only highlight the energy challenges faced by Malaysia and the world today. Malaysia needs to find alternative and less destructive ways to meet the nation’s energy demands, and we must do our part too by understanding that we need to change our lifestyles to one with a lower carbon footprint.