say the dams, pylons and transmission line would destroy forever a true wilderness for short-term energy gains; proponents argue that hydroelectricity is a clean source of energy, that Chile needs the 3,500 megawatts per year of power to meet its development goals of becoming South America’s first developed nation by 2018 and, lacking oil or coal reserves, has no viable alternative.
The country needs to triple its installed capacity by 2025 to meet its energy requirements – currently half the nation’s electricity comes from hydropower and the other half from imported fossil fuels. The Patagonian dams alone could generate one-third of Chile’s electricity, which surely makes the sacrifice of a few remote rivers a small price to pay for such bountiful energy? However, those opposing the dams argue that Chile has one of the longest coastlines in the world, 7,000 kilometres, which is ideal for wind, wave or tidal energy projects; 10% of the world’s volcanoes, so plenty of geothermal potential; one of the world’s strongest solar-energy zones in the Atacama Desert, all of which could provide energy more locally to its point of use without disturbing pristine Patagonia. Confused, I consult an energy expert.
Claudio Zaror, a chemical engineer and energy advisor to the government, is a quietly spoken, slight man who endured the worst of Pinochet’s brutal dictatorship. Kidnapped by the secret police in his twenties, tortured and held for years in a cell sixty centimetres square, he was a lucky ‘disappeared’ – he survived. After decades of deprivation, he wants the lives of ordinary Chileans to improve and has little patience for what he considers unnecessary sentimentality over some remote rivers. For Claudio, the issue is clear-cut: ‘We are a developing nation with nearly 20% of the population living in extreme poverty – I want that number to reduce and we need energy for that.’
Every year the country needs an extra 500 megawatt installed capacity – another 8% annually – because of an increase in population, consumption and industrial growth, Claudio says. ‘If it doesn’t come from the Patagonian dams, it will have to come from a fossil-fuel source with all the carbon emissions that entails, because other renewable energy sources are prohibitively expensive. Environmentally and economically, hydropower is our only feasible option,’ he says.
Climate change is bringing new urgency to the situation, Claudio adds, because droughts are becoming more frequent and severe across the central region, where most of the nation’s hydropower comes from. ‘During the 2008–9 drought, less than 15% of the base-load was met by hydro and we had to import diesel for the power plants at $118 per barrel.’ Meanwhile, with 92% of the country’s glaciers retreating owing to climate change, the glacier melt means there would be strong river flow in Patagonia for the short to medium term.
However, the dams issue remains divisive, not just in Aysén, but across the nation. Surveys show more than half the population is against the proposed dams, but the gap is small enough to cause the government problems whichever decision it takes. The controversy has spilled internationally, as people from around the world claim a stake in this globally unique wilderness. Even the venerable New York Times has waded in with an editorial calling for the dam proposals to be scrapped.
Over the last century, humans have built the equivalent of a dam a day – the vast majority since 1950. Two-thirds of the world’s major rivers have now been disrupted with more than 50,000 large dams – there are more than 85,000 dams in the US alone, stoppering large and small rivers and in most cases utterly transforming natural flow. The most famous of these, the Hoover Dam, constructed in the 1930s, is largely responsible for killing the mighty Colorado River before it reaches the ocean. With a 40% increase in global hydropower predicted by 2050, humanity in the Anthropocene has designs on most major rivers, and controversy over how to use these planetary arteries is only set to increase. In Europe and North America, most of the hydropower potential has now been exploited – indeed some dams are being removed and rivers ‘renaturalised’. In Africa, Asia and South America, though, hundreds of hydrodams are being planned to provide essential electricity for some of the world’s poorest people, and in some of the most ecologically important environments from Patagonia to the Amazon to the Congo. However, the people receiving the new electricity are usually not the same people faced with losing their environment, livelihoods and homes.
Globally, hydropower is an attractive low-carbon source of energy, which unlike solar or wind can produce a continual supply of electricity no matter the weather. Around 20% of electricity worldwide already comes from hydropower. The infrastructure can be relatively inexpensive, is 80–90% efficient and comes with its own battery: the reservoir. This is such a good device that solar- and wind-power generators are increasingly looking to use ‘pumped hydro’ to store their surplus electricity, using it to pump water high up to a reservoir for release when the sun doesn’t shine or there’s no wind. Dammed reservoirs are, of course, also a great way of storing water for drought and modulating damaging floods.
Yet dams, for all their attractive benefits, are also saddled with a lot of negative impacts. Creating the reservoir often involves flooding fertile land, sometimes displacing thousands of people. Communities may lose their land, houses and culturally important sites such as ancestral burial grounds or a landscape that carries strong meaning for them. If the area to be flooded is not adequately cleared of vegetation, methane – a greenhouse gas with twenty-five times the warming potential (over a century) of carbon dioxide – will be released from rotting material. Nearly a quarter of humanity’s methane emissions come from big dams. Stalling a river in a reservoir allows some vegetation to build up and rot anyway, which can poison the water for fish.
The weight of so much water can also cause earthquakes, leading to dam breaches and catastrophic loss of life. In other instances, heavy rains can leave dam managers with the dilemma of whether to try to hold the waters back but risk bursting the expensive dam walls, or releasing the flow, risking flooding people downstream. In many cases, the flow has been released with devastating consequences for lives and livelihoods. In this way, dams that are intended to mitigate flooding can actually result in more serious sudden deluges.
Downstream of a dam, natural seasonal floods that revitalise wetlands and fertilise paddy fields cease. The flow may be so reduced that farmers cannot irrigate their fields and streams are no longer navigable. Migratory fish are often prevented from reaching their spawning areas, other fish have reduced vegetation and may be split from their breeding populations, affecting ecosystems and fisheries. And dams are a barrier to sediment flows. Instead of being flushed downriver, sediments get backed up against the dam walls, which damages the turbines and causes the reservoir level
to increase over time. Downstream, though, the effects of losing nutrient-rich sediments is far more problematic. The fertility of the entire system can be impacted, with soils lost during seasonal rains not being replaced. The upstream–downstream demands often straddle national borders leading to conflict over precious water.
However, the economic benefits can be huge, and the new reservoir can be a haven for wildlife, such as birds, or provide new fisheries and much-needed irrigation security. The Aswan Dam on Egypt’s Nile, for example, was highly controversial when it was built in the 1960s. Yet for all the environmental damage it wreaked on the downstream river system, you’d be hard pushed to find an Egyptian that advocates its removal – the dam has been an outstanding economic success, bringing improved harvests from better irrigation despite drought conditions, as well as hydropower and flood protection worth billions of dollars. Even there though, the river is contested. In 2013, Ethiopia voted to strip Egypt of its right to the majority of the Nile, the source of nearly all of Egypt’s water, paving the way for construction of a massive hydropower dam on the Sudanese border.
As with many development opportunities, hydrodams can be constructed in a way that is minimally socially and environmentally invasive, or in the cheapest way to make the fastest possible return on investment.
In August 2008, HidroAysén, the company behind five of the Patagonian dams, submitted its environmental-impact assessment
