Good Environment: This graph from the Energy Information Administration communicates the reality of renewable energy in America better than any other single source. Renewable energy covers only a small slice, 8 percent, of the country’s needs. And despite the focus on biofuels and solar power, the chart shows that more than a third of that slice comes from hydropower. In the wider world, an even greater proportion of renewable energy comes from hydropower—83.8 percent of renewable generation, according to the International Energy Agency.
The environmental line on hydropower has been that it’s good for the global climate, but bad for the local environment. But as the push for hydropower gains strength in places like Africa and the Amazon, environmental groups are arguing that hydropower contributes to climate change, too. Friends of the Earth International and Rivers International released this Google Earth video that explains how the risks of new, big dams counter their low-carbon footprint, particularly as the world warms up.
The groups argue that climate change exacerbates the hazards of dams, while modifying their benefits. As rivers dry up, hydro projects will produce less energy, less reliably. Dams built now depend on historical data, which won’t predict flows in the future. Melting glaciers and weird weather heighten the risks of floods. A dam is a huge, inflexible investment, and climate change requires adaptation. Large hydropower projects also contribute to water scarcity: Huge amounts of water evaporate from dammed reservoirs.
And although large hydropower projects don’t slough carbon into the atmosphere, they do contribute to climate change by producing methane from rotting algae in reservoirs. There’s some debate about how bad this problem is, but the environmental groups put the impact at the same level as effects from the global air travel industry.
Hydropower doesn’t have to come with these risks, though. Small hydroelectric projects can tap into a river’s energy without damming it. In the United States, a government laboratory put the potential of small hydro at a substantial 30 gigawatts. That energy could come from “run of the river” projects that don’t require dams, or from projects built on existing dams. The Department of Energy is also investing in small hydro pilot projects that could tap lower energy spots on a river. Business Week reported two years ago on a project in Brazil that suspended turbines in the middle of the river. (Like the government-funded Alden Turbine, the project would allow fish to pass freely up and down the river.) Developers can also place small hydro projects in places where they’ll have little environmental impact, like irrigation canals and the streams exiting water treatment plants.
These types of project can’t produce the same scale of energy as large dams can. But they contribute to community resilience by distributing the responsibility for energy generation. In places like Africa, where many communities are not connected to the grid, investing in small, distributed energy projects make more sense than placing a huge bet on a dam. But even in places with robust grids, distributed renewable energy can help mitigate the harms that huge, unsustainable projects require—whatever the energy source.
Shattered Himalaya
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Dams Cannot Protect Against Floods: Expert
The News Pakistan: Despite the fact that Sindh has faced devastating floods in the last two years due to a change in weather patterns, the government is doing little to take measures to minimise the impact of such disasters in future, a visibly worried Naseer Memon tells The News.
“Floods are a relatively predictable disaster,” he said. “And careful monitoring of weather patterns through modern technology can help in predicting floods to a reasonable degree of accuracy.”
Memon is an expert on water management, and, unlike other water experts, he thinks that construction of large dams on the Indus River system will not be of any help. “Dams cannot protect us from floods of such magnitude (as that of 2010). Last year, 1.1 million cusecs of water remained at the barrages of Sindh for 11 days. Any dam of the size of (the proposed dam of) Kala Bagh would have been filled within three days. Also, sudden inflow of floodwater is a threat for a dam’s structure, which if broken could cause even greater damage.”
Idrees Rajput, on the other hand, does not agree with Memon. “A dam can definitely reduce the intensity of floods,” said Rajput, a member of the governing body of the Pakistan Engineering Council. “If a river carries a flood of, say, 20 million acre feet (MAF) of water and there is a dam on the river that can store 7 MAF, then we can say that the magnitude of the flood has lessened.”
But both the experts agree that no dam could have stopped this year’s flood, which was “not a river flood, but a rain flood”. But the government could take some measures to reduce the impact of floods. According to them, removing encroachments from river bodies can really help. “Likewise, a better early warning system in flash flood areas could also ameliorate the effects,” Memon said.
He says that the issue of floods needs much more attention than the government is currently giving it. “For example, Wapda’s Water Vision 2025 does not take climate change into consideration. The Wapda is planning to add 10,000 Mega Watt hydropower through five mega projects, including Bhasha, Kalabagh, Akhori and other dams, by 2016. Estimates for these projects are around 20 billion US dollars. The Wapda has not even the remotest sense of climate change impact on these plans. While Tarbela and Mangla dams are already loosing their capacity owing to heavy silting, newly envisaged dams are bound to meet the same fate as climate change has to result in generating even greater amounts of silt from Himalayas in the coming years,” he wrote in one of articles, Climate Change and the Future of Large Dams.
Climate change is a major challenge for Pakistan, the expert added, as the country receives most of its water from Himalayas where the pace of melting of glaciers has increased due to rising temperatures. More floods are expected in the next three to four decades due to the glaciers’ melting.
What measures should be taken? “The government has to demonstrate political commitment for this. Organisations responsible for disaster management need better attention and adequate technical, financial and human resources. Improving infrastructure planning, stopping deforestation from flood plains and improvising flood protection structures can help in reducing the damage the floods may cause,” he said.
