The Belo Monte Dam project was first proposed to be built over the Xingu River in the Para State of Brazil in the late 1970's. But the project was immediately shelved as it came under major criticism from environmentalists and human activists group. 20 years down the lane, the Brazilian government decided to revisit the project again in the wake of the growing demand for energy in the booming Brazilian economy. Since then there has been an ongoing debate in Brazil centering on the economic and the environmental impact of the dam. In early 2011 the project was given the green signal to go ahead, but it was once again withdrawn on the basis of new objections brought forward in September 2011. 
Belo Monte Dam is a hydroelectric dam, which means it generates electricity from water. Hydroelectricity is the major renewable energy source that counted for almost 16% of the global electricity supply in 2008 . According to a report published by the Intergovernmental Panel on Climate Change (IPCC), the global hydro power technical potential was 14576 as of the year 2009, which is more than four times what's generated right now. The basic principle behind the generation of hydroelectricity is very simple: potential energy of falling water/kinetic energy of running water is converted in to electrical energy through the rotating turbines in a generator. The rotating turbine causes a change in the electromagnetic flux linkages in the generator which eventually induces current in the coil through electromagnetic induction. The power generated depends on several factors, per
where P is the Power, ρ is the density of water, h is the height, r is the flow rate in cubic meters/sec, g is the acceleration due to gravity, and k is an efficiency of coefficient.
It is easier to maximize the power generated through maximizing the height as it increases the potential energy. To maximize the height you would either use the water flowing in from river upstream or build an elevated water storage system, also known as a dam.
The Belo Monte dam is the example of such an elevated water storage. It is planned to have a reservoir area of 500 Sq Km and an installed capacity of about 11000 MW and with capacity factor of 40% this would equate to an annual power generation of 4500 MW . When completed, the installed capacity would make it the third largest dam in the world in terms of power generation. All of this would come at a projected cost of 11 billion dollars which does not include another 2-3 billion dollar projected expense in transmission lines. If we assume that the total cost of the project + transmission cost is 14 billion dollars, we can then calculate the investment cost per MW:
According to Mark Jacobson and Mark Delucchi's paper on cost projection model for hydropower plants, average installation cost per MW of hydropower generated is approximately $2.2 million . Based on that projection the Belo Monte dam seems to be on the highly expensive side and that's without even accounting for the social and the environmental cost that comes with every hydro power plant that's been built in the past.
The sole reason behind the original draft for the Belo Monte Dam being shelved was the environmental impact it was going to have on its surroundings. According to some estimates the Belo Monte Dam would potentially displace 16,000 natives from their ancestral grounds and endanger 1000 reptile, bird and fish species .
Already termed as the 'Monster Dam,' Monte Belo Dam would require up to 80% of the Xingu river to be diverted from its original course to feed the dam complex. This would create a serious drought for Juruna and Arrara natives living in the Paquicamba and Arara territories, who depends on the river for fishing and water supply. Also to divert this massive amount of water, the project would require building two artificial canals, the excavation of which would see more land removed from the earth then the construction of the Panama Canal .
Besides the regional impact there is also the general environmental impact that most hydro power construction eventually leads to. These includes large amount of methane emission from rotting trees and plants in stagnant reservoir water. Most of these plants have tied up carbon which is then released as methane once the trees start to rot in the reservoir water . Although there is no debate on the fact that hydro power dams do eventually emit methane to a certain extent but there is serious contention about the cost benefit ratio of this methane emission as hydropower plants don't burn any fossil fuel like other power generating sources (the fossil fuel spared could have led to more emission).
Brazil is going through the same industrialization period that most developed countries in the west went through a few hundred years ago. If you look at the energy consumption and greenhouse gas emission of that period by those countries, it would be hard to object to Brazil's effort to build the Belo Monte dam to support its booming economic growth. But still, if we look at the current scenario and look at the social and environmental cost of building the dam (some say the environment impact outweighs the economic cost of the project) then we do have to stop and think as to how feasible it is in terms of Brazil's plan to become the next developed nation. If all the concerns and estimates are right, then Brazil would have to risk the lives of hundreds of indigenous people (and endanger thousands of bird and marine species) for the sake of the economic growth of the nation.
© Navid Chowdhury. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
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