My old friend and fellow journalist McKenzie Funk hipped me to a really impressive piece of reporting out of Brazil. The Folha de Sao Paulo (the nation’s largest newspaper) has produced an immersive study of the Belo Monte project, which will see the construction of the third most productive hydroelectric dam in the world—and the destruction of a sizable patch of rainforest and the displacement or death of its human and wild denizens.
The Folha piece is long, but worth your time. The United States had largely completed its iconic hydro projects by 1970, two generations ago (Hoover, 1934; Grand Coulee, 1942; Glen Canyon, 1966). It’s easy to assume that the rest of the world worked on the same timeline. But it didn’t. Major hydroelectric projects are underway all over the globe, as billions of people enter the modern, electrified economy for the first time. Each dam forces a difficult cost-benefit decision, with economic (and downstream) benefits on one side and environmental and social disruption on the other. The Folha piece illuminates the universal conundrum with its remarkably deep and broad study of Belo Monte.
I’m interested in dams in part because they are often built expressly to power mines and smelters. This is not the case with Belo Monte, which will power homes and businesses in Brazilian cities, but not all that far to its north is the example par terrible. The Afobaka Dam, in Suriname, was built by Alcoa in the early 1960s to provide electricity to its major aluminum operation there. Afobaka is about as simple as dams come. It’s an earthen dike, or embankment, with a single concrete section housing a hydro plant. But it is remarkable in one way: it is by far the least efficient hydroelectric dam ever built.
One way to express the efficiency of a hydro project is in hectares per megawatt—that is, the area flooded by the dam’s reservoir relative to its electrical output. A 2003 World Bank report (“Good Dams and Bad Dams”) ranks 49 significant projects according to this criteria. At one extreme, the Arun II dam in Nepal and Pehuenche dam in Chile have ratios of less than one: each flooded hectare generates more than a megawatt. At the other extreme is Afobaka (a.k.a. Brokopondo). It produces a measly 30 megawatts. But to get it, the dam drowns more than 1,500 square kilometers of Surinamese jungle. That works out to an appalling 5,333 hectares per megawatt. The drowned area is considerably larger than Los Angeles. The electricity would barely keep the lights on in Barstow.
Measured by this metric, Belo Monte is among the “best” dams in the world: Its hectares-to-electricity ratio is just over 4. At 11,000 megawatts from a reservoir of 45,000 hectares, Belo Monte will produce 366 times more electricity than Afobaka while flooding an area only a third as large.
But, of course, the moral calculus for building Belo, and any dam, is much more complex and much less black-and-white than a simple ratio. As mining firms, bringing with them the dams they need, seek to push further into the remaining wild corners of the globe, it’s to be hoped that those doing the math look beyond the value of a mine’s ore, and beyond the few decades of a mine’s working life, when answering the question of whether to build. The world needs what mining produces. But mining doesn’t need to produce another Afobaka.
Image of drowned trees in the Brokopondo (Afobaka) Reservoir. By Rutger Hermsen / Creative Commons.