Dams and climate change


in Economics, Politics, The environment

Emily Horn, looking sad with some skulls

In the past, environmental groups have often opposed hydroelectric projects, both in the form of large dams and smaller run-of-river projects. Now, I think the seriousness of climate change overrides past objections about destroying habitat and disrupting ecosystems in rivers. While we should definitely take cost-effective measures to reduce the harmful impacts of dams (for instance, removing trees from the area that is to be flooded), I think we need to accept more dam construction as a necessarily part of moving to a sustainable low-carbon economy.

Dams have virtues as a consistent source of energy for electrical generation. Their variable output also means they can be used to balance out production from sources like wind farms and solar facilities. With pumped hydroelectric storage, dams can also save energy at times when production exceeds demand, and do so in a way that is reasonably efficient.

Climate change impacts also support the call for more dams. The loss of glaciers and snowpack mean that natural water flows are going to become more variable. More and larger dams could help to smooth that out, as well as compensate for how our current hydroelectric infrastructure will face challenges as a result of decreased summer water flow.

Climate change is making many people re-think nuclear power, a source of electricity with a lot more black marks against it than hydroelectricity has. As such, I think we should be glad that many past attempts by environmentalists to block dams have failed, and we should strive to support their further development where suitable sites exist.

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{ 63 comments… read them below or add one }

. March 26, 2009 at 12:32 pm

In the Fight Over Clean Energy, Will “Environmentalists” Stand With Science?

By Professor Andrew Weaver, Lead author for the Nobel Prize-winning Intergovernmental Panel on Climate Change.

Switching from fossil fuels to emissions-free energy sources is not going to happen without resistance. Each new hydro and wind project is being opposed by well-meaning citizens and environmental groups not familiar with the science. Each energy conservation policy is fought bitterly by “public interest groups” demagoguing to keep energy subsidized. Each attempt to tax carbon and each law to reduce emissions draws the fossil fuel lobby into action alongside these “public interest” groups.

The public debate has become a caricature. People complain about windmills blocking their view. Kayakers complain about seeing a transmission line on their weekend excursions. The public dialogue is riddled with outlandish and demonstrably false assertions such as windmills will devastate local bird populations or a hydro project will create more greenhouse emissions than it will displace by eliminating a coal-burning power plant. Some of the most insidious arguments attempt to slow things down: that we should do more planning, that we should do energy conservation first and build renewable energy later, that we shouldn’t do anything until China does.

These arguments are fundamentally not serious. They come from groups and spokespeople that have simply not grappled with the math — with the scale and speed at which we must eliminate fossil fuel emissions.

. March 26, 2009 at 12:33 pm

Backlash Against the Green Economy in BC
by Tzeporah Berman

To vote against cap & trade or carbon taxes, or to campaign against renewable energy companies being allowed on the grid or against energy conservation, is to act against the reports of the Nobel Laureates on climate science and policy. It may stick in the craw of environmentalists like me to say so, but we need to be grateful to the previous generations that built the mega dams and gave our generation such a head start towards a clean grid which could become the basis for a green economy. Those who fought big hydro dams back in the day did not have the knowledge of global warming that we have now, but we are lucky environmentalists lost most of those fights. And we must not make the mistake of acting against emission-free power in the face of all the science available today.

. March 26, 2009 at 9:49 pm

Hydroelectricity >> Disadvantages

Hydroelectric projects can be disruptive to surrounding aquatic ecosystems both upstream and downstream of the plant site…

The reservoirs of power plants in tropical regions may produce substantial amounts of methane and carbon dioxide. This is due to plant material in flooded areas decaying in an anaerobic environment, and forming methane, a very potent greenhouse gas…

Another disadvantage of hydroelectric dams is the need to relocate the people living where the reservoirs are planned…

Failures of large dams, while rare, are potentially serious — the Banqiao Dam failure in Southern China resulted in the deaths of 171,000 people and left millions homeless…

Changes in the amount of river flow will correlate with the amount of energy produced by a dam.

oleh March 27, 2009 at 7:11 am

I agree that changing conditions warrant changing priorities. Hydro-electiric power which generally requires dams and transmission lines are an increasingly better alternative. Also the negative effect of those dams is somewhat mitigated by our increased knowledge and regulatory and environmental assessments. ( I admit that I never was particularly troubled by dams in general )

Tristan March 27, 2009 at 9:05 am

If you don’t remove organic matter from the area being flooded, there is a serious chance that the damn will produce more Co2 than the equivalent coal plant. Such precautions can’t only be taken when “cost effective”. What’s worse, is that trees don’t make up the totality of the problem – what do you think the dirty is made from?

The sad fact is, there are precious few sites where dams can be built without massive Co2 production resulting, and they are mostly already used. We see the dam and it looks relatively small – it is difficult to conceive of just how much earth is flooded – all earth which has to either be removed down to bedrock, or will rot.

. March 27, 2009 at 10:25 am

Hydroelectricity >> Disadvantages >> Greenhouse gas emissions

According to the World Commission on Dams report, where the reservoir is large compared to the generating capacity (less than 100 watts per square metre of surface area) and no clearing of the forests in the area was undertaken prior to impoundment of the reservoir, greenhouse gas emissions from the reservoir may be higher than those of a conventional oil-fired thermal generation plant.

In boreal reservoirs of Canada and Northern Europe, however, greenhouse gas emissions are typically only 2% to 8% of any kind of conventional fossil-fuel thermal generation

Milan March 27, 2009 at 10:28 am


Do you have any sources to quantify the emissions you are talking about? The report cited in Wikipedia suggests that they are only a major concern in a minority of cases.

Also, and sources on the number of viable sites available? At least a few sites are very likely to be developed in Canada: Lower Churchill, among them.

. March 27, 2009 at 10:39 am
. March 27, 2009 at 10:46 am

From Part II:

“The scientific literature shows that reservoirs can emit CH4 due to the anaerobic decomposition of
biomass and CO2, and that in some particular circumstances, this can be substantial and of a similar
order of magnitude as the thermal emissions avoided. At least two reservoirs have been shown to
emit quantities of CH4 equivalent to, or in excess of, the GWP of thermal emissions of CO2 avoided
(Balbina in Brazil and Petit Saut in French Guyana). Others, such as Tucurui and Itaipu, also emit
CH4 but not in quantities sufficient to put at risk the climatic benefits of such huge hydroelectric plant.
Tropical reservoirs that are shallow and uncleared of biomass appear most at risk. Scenarios are
calculated showing that in cases where the power generated by the hydroelectric plant is less than 0.1
W/m2 of reservoir area, then there is a risk that the GHG emissions may exceed the thermal emissions
avoided. Where values exceed 0.5 W/m2 of reservoir the scenarios show the possibility of reservoir
emissions putting at risk the benefits of CO2 avoided by hydroelectric scenarios…

In general it can be said that the risk of CH4 emissions can be reduced by :

* avoiding low W/m2 ratios (i.e around 0.1)
* clearing the reservoir of all biomass prior to flooding”

Milan March 27, 2009 at 10:48 am

This suggests that there may be a trade-off between climate change mitigation and adaptation. Dams with big capacities can help take the place of winter snowpack and glaciers, reducing summer drought danger. At the same time, higher capacity dams generally have higher associated greenhouse gas emissions.

Certainly, all the interconnections between dam construction and climate change ought to be taken into account when doing energy supply planning.

Tristan March 27, 2009 at 1:04 pm

I’d like to thank . for the fantastic information gathering. It’s nice to have all these resources linked from one convenient location.

It’s nice to see a clear number associated with the varying risk. Now we can calculate quite easily whether site C will have a chance at producing less C02 than the thermal equivalent.

Milan March 27, 2009 at 1:13 pm

The Site C page on Wikipedia is a bit vague:

“The dam would flood 50 miles of river valley and farmland to create a reservoir for the 900 megawatt project.”

Do they mean fifty square miles, or a length of river fifty miles long? If we knew the planned extent of the reservoir, we could calculate a W/m2 ratio. It would also be useful to know what kind of ecosystems will be flooded, and what sort of biomass clearing is planned.

Tristan March 27, 2009 at 1:14 pm

Site C promises to flood 5,340 hectares, “about half” forest. So that’s 53,400,000 square meters.

It promises about 900megawatts. So, that’s 900,000,000 (900 million) watts, divided by 53 million square meters. So, 45 watts per square meter?

Wow, it’s a fantastic deal.

Milan March 27, 2009 at 1:17 pm

To me, it seems like rocky canyons are the ideal locations for dams, since you can just fill up the space between the canyon walls without flooding large areas of countryside.

Is there any reason why rivers in rocky canyons can’t have a whole string of dams build along them, with each reservoir starting near the base altitude of the previous dam?

It would be apocalyptic for migrating fish and animals that live in the canyon, but it seems like it could produce a lot of energy for a relatively small environmental impact.

Milan March 27, 2009 at 1:28 pm

45 watts per square metre does seem pretty good. By comparison, a 100% efficient solar cell could produce about 1370 watts per square metre. Commercial solar cells range from about 10% efficiency up to over 40%, though the latter use exotic materials and are very costly.

As such, building Site C would be akin to covering the flooded area with 3% efficient solar cells that worked constantly. That’s not a great efficiency level, but the dam would probably be a lot cheaper than 900 megawatts worth of solar capacity. It would also operate closer to peak output more of the time.

(A better figure for solar irradiance would take into account the latitude of the site and the weather there.)

Tristan March 27, 2009 at 5:34 pm

“To me, it seems like rocky canyons are the ideal locations for dams, since you can just fill up the space between the canyon walls without flooding large areas of countryside.”

This is true in practice, where there are rocky canyons, humans are good at filling them up with dams. Certainly there is room for improvement. One thing to consider is if a river has had no dams on it, it will still have fish. Putting the first dam in causes massive ecological devastation, but after that, the detestation is much more minor. This is why it makes sense that the Fraser has zero dams on it, while the Columbia has a million. (Or at least a few dozen).

. March 27, 2009 at 5:44 pm

List of dams in the Columbia River watershed

Total Capacity (MW): 24,149

. March 27, 2009 at 5:45 pm

Water battery: Riverbank Power brings new twist to pumped storage
March 23rd, 2009

Riverbank does pumped hydro storage, but not like conventional projects that require the right geography and topology (i.e. a large natural reservoir hundreds of metres over lake level).

Riverbank depends more on geology. It looks for brownfield sites that are located next to a large body of water and transmission lines (with adequate capacity). It then digs a few deep holes to figure out the rock conditions. If the rock is hard and if the site meets all other conditions, it will excavate massive caverns 600 metres below the surface that can safely contain 3.8 billion litres of water.

Anon March 27, 2009 at 6:04 pm

Incidentally, the ‘business-as-usual’ emissions estimates produced by some governments already include the planned construction of new large dams.

If those projects were blocked for some reason, even greater cuts elsewhere would be necessary in order to meet emission targets.

. April 6, 2009 at 12:45 pm

A North American Energy Plan for 2030: Hydro-electricity the forgotten renewable energy resource

Posted by Big Gav on April 6, 2009

Hydro energy’s potential may be overlooked because; it is “old” renewable energy, or because like nuclear energy, some hydro electric schemes have been criticized by environmental groups, but most importantly a perception by many, that most hydro electric potential in North America has already been exploited. Hydro electricity deserves more scrutiny because;

1) North America has significant undeveloped potential,
2) the technology is well understood, although technical improvements continue to be made, especially for low head and small hydro,
3) hydro has a very high energy return on energy investment (ERoEI),
4) additional hydro can enable more wind and solar energy capacity to be absorbed by the grid,
5) hydro potential is more geographically dispersed than wind and solar, and finally,
6) the cost of developing additional hydro capacity is moderately low and has very low technical and financial risk.

. April 17, 2009 at 12:41 pm

Then we come to the run of the river projects in British Columbia. Properly regulated RoR can be some of the least environmentally obtrusive forms of electricity production. The public discourse has been hijacked through greenwashing by those opposed to the privatization of energy and the potential impact on union jobs.

Where is the informed discussion on the proper regulatory framework that would allow RoR to proceed with the smallest ecological footprint?

And if we can generate excess green energy in B.C., a province blessed with so much potential for renewable energy production, we could export that energy to Alberta or the U.S. and displace energy production from highly polluting coal-fired electricity plants.

. April 22, 2009 at 11:34 am

World’s major rivers ‘drying up’
By Matt McGrath
BBC environment reporter

Water levels in some of the world’s most important rivers have declined significantly over the past 50 years, US researchers say.

They say the reduced flows are linked to climate change and will have a major impact as the human population grows.

The only area with a significant increase in water flows was the Arctic due to a greater snow and ice melting.

The study was published in the American Meteorological Society’s (AMS) Journal of Climate.

. June 1, 2009 at 4:11 pm
. June 12, 2009 at 1:36 pm

Environment fears halt China dams

China’s environment ministry has suspended construction of two dams on a tributary of the Yangtze River.

The projects on the Jinsha River had been started without environmental assessments or approval from the ministry, officials said.

The dams are part of a series of eight power stations planned for the Jinsha.

The $30bn (£18bn) project has been criticised by conservationists, who say it will damage the region’s environment and biodiversity.

The power stations are expected to generate as much electricity as the controversial Three Gorges Dam – about 20 gigawatts.

The series of hydro-electric stations is planned for a 560km (350 mile) stretch of the Jinsha River in south-west China’s Yunnan province.

. July 20, 2009 at 12:45 am

The Rampart Dam was a hydroelectric power proposal in the 1950s and 1960s by the U.S. Army Corps of Engineers to dam the Yukon River in Alaska, United States. The project was planned for Rampart Canyon, about 105 miles (169 km) west-northwest of Fairbanks, Alaska. The resulting dam would have created a lake roughly the size of Lake Erie, making it the largest man-made reservoir in the world. The plan for the dam itself called for a concrete structure 530 feet (162 m) high with a top length of about 4,700 feet (1,430 m). Though supported by many politicians and businesses in Alaska, the project was canceled when concerns arose about the project’s cost. Native Alaskans in the area protested the threatened loss of nine villages that would be flooded by the dam. Conservation groups abhorred the threatened flooding of the Yukon Flats, a large area of wetlands that provides a critical breeding ground for millions of waterfowl. Fiscal conservatives opposed the dam on the grounds of its large cost and limited benefit to Americans outside Alaska. Because of these objections, United States Secretary of the Interior Stewart Udall formally opposed construction of the dam in 1967, and the project was shelved.

. August 23, 2009 at 4:56 pm

Russia plant disaster toll rises

The death toll from Monday’s accident at Russia’s largest hydro-electric plant has risen to 67, officials say.

They say eight people are still missing after a massive surge of water in the turbine hall at the Sayano-Shushenskaya plant in Siberia.

Rescue and clean-up operations are continuing, but officials say chances of finding any survivors are slim.

The cause of the accident on the plant on the Yenisei River remains unclear and an investigation has been launched.

. August 23, 2009 at 5:03 pm

Harper makes Yukon hydro expansion funding official

Last Updated: Friday, August 21, 2009 | 5:49 PM CT

Prime Minister Stephen Harper signed off on the federal government’s contribution to Yukon Energy Corp.’s $160-million upgrade to its Mayo hydroelectric dam on Friday, the final day of his northern tour.

Harper boarded a helicopter Friday morning to tour the Wareham hydro dam near the central Yukon community of Mayo, overlooking the scenic Stewart River. He was joined by Yukon Premier Dennis Fentie and Yukon Energy officials.

In May, the federal government said it would commit $71 million toward expanding the Mayo facility. That funding was the first to be announced under its $1-billion Green Infrastructure Fund.

. September 21, 2009 at 10:45 am

‘Millions at risk’ as deltas sink
By Richard Black
Environment correspondent, BBC News website

Most of the world’s major river deltas are sinking, increasing the flood risk faced by hundreds of millions of people, scientists report.

Damming and diverting rivers means that much less sediment now reaches many delta areas, while extraction of gas and groundwater also lowers the land.

Rivers affected include the Colorado, Nile, Pearl, Rhone and Yangtze.

About half a billion people live in these regions, the researchers note in the journal Nature Geoscience.

They calculate that 85% of major deltas have seen severe flooding in recent years, and that the area of land vulnerable to flooding will increase by about 50% in the next 40 years as land sinks and climate change causes sea levels to rise.

“We argue that the world’s low-lying deltas are increasingly vulnerable to flooding, either from their feeding rivers or from ocean storms,” said Albert Kettner from the University of Colorado in Boulder, US.

“This study shows there are a host of human-induced factors that already cause deltas to sink much more rapidly than could be explained by sea level alone.”

Most of the at-risk river basins are in the developing countries of Asia, but there are several in developed nations as well, including the Rhone in France and the Po in Italy.

The Po delta sank by 3.7m during the 20th Century, mainly from methane extraction, the researchers say.

. September 25, 2009 at 11:14 am

The Vajont Dam
By RobK on Structures

High up in the Italian Dolomite mountains, 90km north of Venice, the Vajont Dam was the scene of one of the 20th century’s worst engineering disasters. The tallest dam in the world when it was completed in 1959, at 262m, it was beset with problems from the beginning. On October 9, 1963, before it had even been completely filled, an enormous landslide (the 2km-long scar of which can still be clearly seen) sent 260 million cubic metres of mountainside into the lake behind the dam, causing a wave of water 250 metres high to spill over into the valley below.

The giant wave completely destroyed five villages, killing almost 2,000 people, maybe even more. Strangely, the dam itself was relatively undamaged and still stands today, with the upstream face largely buried beneath the landslide. Although the communities (the largest of which was Longarone) have been rebuilt, they are very different places than before the disaster. Many of the survivors were relocated to a newly built town 35km away, also called Vajont, and the valley is now home to many more industries. Apparently this has been a source of controversy in the area: the victims were offered tax breaks by the government to help them rebuild their lives, but many of these privileges ended up being bought from them by large corporations.

. October 15, 2009 at 12:33 pm

The trouble facing Canadian rivers

Canada’s major waterways have suffered significant alterations in their natural flows, a WWF-Canada report contends

Martin Mittelstaedt

From Thursday’s Globe and Mail Published on Wednesday, Oct. 14, 2009 8:16PM EDT Last updated on Thursday, Oct. 15, 2009 2:35AM EDT

The seasonal waxing and waning of rivers is one of nature’s most crucial cycles, influencing everything from the success of salmon runs to having enough water during parched summers to irrigate crops.

But by this measure, many of Canada’s major rivers are in trouble, contends a new report that says many of the best known rivers have suffered major alterations in their natural flows due to hydro dams, irrigation schemes and withdrawals by industry, and could be further compromised by the effects of global warming.

The report, by WWF-Canada, one of the country’s major environmental organizations, says the rivers that have been most altered from their natural state include the St. Lawrence and the South Saskatchewan, whose “ecosystems are in serious trouble” as a result. But it warned that if safeguards aren’t put in place soon, some of North America’s last free-flowing rivers, including the Skeena in B.C., the Athabasca in Alberta, and the Mackenzie in the Northwest Territories “could soon be in trouble as well.”

. October 23, 2009 at 10:51 am

A Lot of Hydro Power Depends on Glaciers, and We All Know What’s Happening to Those…

A study by Lausanne’s EPFL technical university forecast a decline to 46 percent by 2035 for hydro from around 60 percent now as precipitation declines and total energy use increases.

In the same way as the Himalayas are “Asia’s water-tower,” Switzerland is the source of Europe’s biggest rivers, supporting agriculture and waterways, and cooling nuclear power stations.

Philip Beck November 30, 2009 at 10:01 am

Hi : fantastic info on this thread, well done.
I’m doing some investigations for the Spirit of Ireland project and I wonder if any of you have come across any prior projects that resemble it ? The basic idea is to deal with the intermittency of wind by using the electricity generated by wind turbines to pump seawater from sea level up U-shaped valleys, store it behind dams, and let it flow down through flexible load hydro turbines to meet demand from the national grid.
Any references very welcome ! Thanks, Philip (www.spiritofireland.org )

Milan November 30, 2009 at 10:04 am
. April 27, 2010 at 11:09 am

“Site C is a “clean energy project” – a catch phrase that’s used repeatedly because it plays to sensibilities of a population left jittery by global warming threats.

But it is open to debate as to whether or not that is an accurate description.

Andrew Weaver, the eminent, Cambridge educated expert on atmospheric sciences from the University of Victoria, thinks it is.

“Yes, it meets the definition of clean energy,” he says, pointing out that hydro power is just about as clean as it gets.

Dr. Weaver is quick to acknowledge that greenhouse gases will be produced by the massive construction effort needed to build the dam. And he agrees that emissions will be released when vegetation rots in the reservoir that will be created.

But relatively speaking, the amounts of greenhouse gases produced will be minor, he says, and once up and running, Site C will be generating clean energy for a long time to come.

. May 10, 2010 at 9:51 am

Energy in Brazil
Power and the Xingu
A huge Amazon hydropower project shows how hard it is to balance the demands of the environment and of a growing and prospering country

Apr 22nd 2010 | RIO DE JANEIRO | From The Economist print edition

A generation ago similar protests over an earlier version of the same dam—known then as Kararao—forced officials to rethink their strategy. They came up with Belo Monte. It was not just a marketing ploy. Instead of building a great wall across the Xingu to create a massive reservoir, Belo Monte is designed as a run-of-river dam, a technique that harnesses the natural flow of the river to drive the turbines.

The new version will still flood a lot of forest: a reservoir of 516 square kilometres (200 square miles) will leave scores of villages awash and force thousands from their homes. But that is a third of the area that the original dam would have inundated. The consortium has committed to help relocate the displaced and patch up any damage to the environment.

But these environmental safeguards will also curb Belo Monte’s capacity to generate power, which will vary with the flow of the Xingu. When swollen by the rainy season, the river will cascade through the turbines, turning out up to 11,200 megawatts—adding 10% to Brazil’s existing generating capacity. But during the dry Amazon summer, when the Xingu shrinks, Belo Monte’s assured output will plunge to an average of 3,500-4,500 megawatts. Add in the likelihood that the rate cap leads to escalating subsidies, and no wonder that some Brazilians wonder whether an all-too familiar species has re-emerged in the Amazon: a white elephant.

But with the economy set to grow by up to 7% this year, and tens of millions of Brazilians consuming more after leaving poverty, investing in more power generation is essential. The protesters want smaller wind or solar plants. But without Belo Monte, Brazil would probably have to build nuclear power plants or invest in coal-fired thermal energy. And then the protests would no doubt be even bigger.

. May 12, 2010 at 1:35 pm

Dams in Africa
Tap that water
Controversy surrounds the argument for dam-building in Africa

May 6th 2010 | NAIROBI | From The Economist print edition

AFRICA is the “underdammed” continent. It is the least irrigated and electrified, yet it uses only 3% of its renewable water, against 52% in South Asia. So there is plenty of scope for an African dam-building boom. Ghana long ago dammed the River Volta, Egypt the Nile, Zambia, Zimbabwe and Mozambique the Zambezi. But there are new projects aplenty.

Sudan’s president, Omar al-Bashir, for instance, is so proud of the new Merowe dam in the north of his country that he made it a selling-point in his recent election campaign. Costing $1.8 billion, it will produce 1,250 megawatts and create a lake 174km (108 miles) long, above the Nile’s fourth cataract. If all goes well, it may even fulfil an old dream to irrigate swathes of farmland in northern Sudan, while sending electricity to run the thirsty air-conditioners of Khartoum. And all without dirtying the atmosphere, once the dams have been built.

China is building most of Africa’s new dams out of its own pocket, with all sorts of hoped-for spin-offs. International Rivers, a lobby that tries to save rivers from dams it says are destructive, admits that the Chinese are much greener these days. China Eximbank cancelled a loan for a dam in Gabon on environmental grounds. Even so, political instability, graft and incompetence have meant that many African dams, once built, have failed to produce what was promised. The Inga I and II dams on the Congo river have generated a fraction of the power they were meant to. The technology is demanding. Seasonal rains produce muddy rivers, with higher sedimentation than northern countries’ dams filled with melted snow. That means a shorter lifespan and heavier maintenance. Angola has spent $400m overhauling its dams and transmission lines.

. June 9, 2010 at 4:32 pm

A special report on water
The ups and downs of dams
Small projects often give better returns

May 20th 2010

The Aswan high dam, for example, is often cited as a cautionary example, a quixotic construction that now reduces the mighty Nile to a dribble before it trickles to the sea, leaving behind an explosion of water hyacinth, outbreaks of bilharzia, polluted irrigation channels and a build-up of sediment inland that would otherwise compensate for coastal erosion from Egypt to Lebanon. Yet, according to the World Bank, it has provided a bulwark against flooding for buildings and crops, a huge expansion of farming and Nile navigation (lots of tourism) and enough electricity for the whole of Egypt—all of which amounts to the equivalent each year of 2% of GDP in net benefits.

So would the World Bank today lend money for an Aswan dam if it did not already exist? The bank has been involved in few of the 200 or so large dams built in the past five years, but that is mainly because dam-builders—of which China is much the biggest—do not care for the bank’s time- and money-consuming regulations, designed to ensure decent technical, social and environmental standards. Their strictness partly reflects greater knowledge about the consequences of building dams, partly the related political controversies of the 1980s. Even so, the bank was involved in 101 dam and hydro projects in 2007, up from 89 in 1997 and 76 in 2003; and it approved over $800m in hydro lending in 2008, up from $250m in 2002.

Suspicions of big dams still run high—and with some reason. Mr Thakkar, scrutineer of the Indian water scene, says that although the installed capacity of India’s hydro projects increased at a compound rate of 4.4% a year between 1991 and 2005, the amount of energy generated actually fell. Some of the projects, poorly sited or poorly designed, were doomed to be uneconomic from the start. Others have been badly maintained or have simply silted up. But though 89% of the country’s hydro projects operate below design capacity, the building continues wastefully apace.

. July 26, 2010 at 3:02 pm

Dammed if they do
China’s hydropower plans are a test of its avowed good neighbourliness

Jul 8th 2010

“The Chinese press steers clear of dams with a barge-pole. Academics and NGO representatives who oppose the dam-building on social or environmental grounds do not want their names published. In private even academics in favour of hydropower development complain that nearly all relevant information, even the amount of rain that reaches them, is treated as a state secret. (Though, they add, at China’s meteorological and rivers bureaus, even state secrets can be imparted if the price is right.)

Until recently China was no less communicative towards downstream neighbours, who have seen a sharp drop in Mekong levels in recent years. Thailand, Laos, Cambodia and Vietnam complain that China neither consults nor informs them about what it is up to. For all that it preaches harmony and good neighbourliness, China comes across as a regional bully, with its foot on the Mekong’s throat. The Mekong basin is the greatest inland fishing region in the world. Distraught Thai, Laotian and Cambodian fisherman and farmers blame Chinese dams for killing off fish stocks, cutting irrigation and disrupting livelihoods. Recently a Bangkok Post editorial accused China of “Killing the Mekong”.

In March China broke its silence over dams, denying that it was responsible for reducing the Mekong’s flow reaching downstream neighbours. It blamed instead the drought, from which China has suffered as much as anyone. The truth lies somewhere in between. Less than one-sixth of the total Mekong catchment is in China, but that upstream flow is crucial to neighbours during the dry season. China has held some of the dry-season flow back.”

sitanon jesdapipat November 8, 2010 at 2:31 am

Points well taken. But there are more to consider. Not every country could build dams, and not all the dams should be built. The ultimate point is the purpose of building dams. Then how to build them environmentally friendly. And, operate them sustainably…
Dams could cause desertification in some areas. Dams could also lower ground water in others. Building a dam is not sufficient in itself. One has to ensure that it has water, and that it could store water. It could deliver what has been promised.

. April 5, 2011 at 10:59 pm

Michael Ignatieff has matched Stephen Harper’s committment to the lower Churchill project — and taken it a step further.

Both the Liberal leader and the Conservative leader have promised loan guarantees for the $6.2-billion project. But now Ignatieff is proposing a federal role in a larger and more lucrative project on the same river system.

Calling the current hydro proposal the lower Churchill project is really a misnomer. What everyone is talking about is the Muskrat Falls development. Its an 824 MW project that would see Labrador power brought to the island of Newfoundland and into Nova Scotia using a system of subsea cables.

Muskrat Falls is the current project. But Gull Island is the government’s dream development. The Gull Island rapids are part of the same river system as Muskrat Falls and the original Churchill Falls development. Gull Island has the potential to produce 2,250 MW — nearly three times the size of Muskrat Falls. Nalcor calls it the best untapped hydro project in North America.

The problem with developing Gull Island has been an unrelenting border war between Newfoundland and Larbador and Quebec. The best market for its power is in southern Ontario and the northeastern United States. To get there, Gulls Island power needs to ride Quebec’s transmission wires.

. May 2, 2011 at 6:20 pm

The River Nile
A dam nuisance
Egypt and Ethiopia quarrel over water

Apr 20th 2011 | ADDIS ABABA | from the print edition

MOST of the water meandering down the lower reaches of the Nile, the world’s longest river, comes from the Ethiopian highlands, putting rulers in Addis Ababa, the capital, in a position of unusual power, one they have rarely dared to exploit. But since Egypt, the biggest and most influential consumer of Nile water, is distracted by revolutionary upheaval at home, this may be changing. Ethiopia and the other upstream countries—Burundi, Congo, Kenya, Rwanda, Tanzania and Uganda—have banded together to rewrite a 1959 treaty that favours Egypt.

They may succeed. After decades of strong population growth, Ethiopia has overtaken Egypt as Africa’s second-most-numerous nation. The total population of the upstream countries is 240m against 130m for the downstream duo of Egypt (85m) and Sudan (45m), whose 14m southerners will soon be independent and are being courted by both sides.

. July 3, 2011 at 10:49 am

China and opposition to dams
Choking on the Three Gorges
China’s government at last owns up to problems at its monster dam

Jun 9th 2011 | BEIJING | from the print edition

RAIN along the middle and lower Yangzi River this week has helped alleviate the region’s worst drought in 50 years. But it has not doused a storm of criticism of the Three Gorges dam upriver, including allegations that it contributed to the disaster. Opponents of the colossal edifice have been emboldened by rare government admissions of environmental and other “urgent” problems caused by the dam.

In private, officials have worried about the project for some time and occasionally their doubts have surfaced in the official media. But the government itself has refused to acknowledge them. When the project was approved by the rubber-stamp parliament in 1992, debate was stifled by the oppressive political atmosphere of the time, following the Tiananmen Square massacre three years earlier. Last July, with the dam facing its biggest flood crest since completion in 2006, officials hinted that they might have overstated its ability to control flooding. On May 18th, with the dam again in the spotlight because of the drought, a cabinet meeting chaired by the prime minister, Wen Jiabao, went further in acknowledging drawbacks.

Having called the dam “hugely beneficial overall”, the cabinet’s statement said there were problems relating to the resettlement of 1.4m people, to the environment and to the “prevention of geological disasters” that urgently needed addressing. The dam, it said, had had “a certain impact” on navigation, irrigation and water-supply downstream. Some of these problems had been forecast at the design stage or spotted during construction. But they had been “difficult to resolve effectively because of limitations imposed by conditions at the time.” It did not elaborate.

. July 18, 2011 at 7:29 pm

ENERGY Deal aims to rekindle Bute Inlet hydroelectric project

JUSTINE HUNTER VICTORIA Alterra Power hopes to resurrect an ambitious run-of-the-river project that would rival the capacity of BC Hydro’s proposed Site C dam.

To do so, Alterra is signing a partnership agreement with the Homalco First Nation on Friday, handing the tiny band $1.5-million in exchange for an agreement that would allow the Bute Inlet hydroelectric project to proceed in its traditional territory.

The Bute Inlet project stalled last year when Plutonic Power, the developer, dropped out of the running for a power-purchase agreement with BC Hydro, citing confusion over the province’s clean-energy policies.

Plutonic Power merged with Magma Energy earlier this year to create Alterra and is now moving forward again. The pact with the Homalco promises the band significant benefits if the project proceeds, including a share of potential revenues and right of first refusal on contracts.

The project has the potential to create 1,030 megawatts of electricity – compared to the $8-billion Site C megaproject, which would generate 1,100 megawatts by building a third dam on the Peace River. Alterra’s project, opposed by a number of environmental organizations, would partly dam creeks and rivers with 17 power facilities in the glaciated Coast Mountains above Bute Inlet, located roughly 250 kilometres northwest of Vancouver, and it would require power lines to connect to the provincial grid.

. November 13, 2011 at 10:45 am

Climate research exonerates giant dam

Edward Wong November 14, 2011

BEIJING: A scientific study has found that the Three Gorges Dam, the world’s largest hydro power project, has not contributed to climate change, a report by Xinhua, the Chinese state news agency, says.

The study, published by the Social Sciences Academic Press under the Chinese Academy of Social Sciences, focused on climate change and found that the dam’s environmental impact was limited to a 20 kilometre radius, the Xinhua article said.

”No direct link has been found between the dam and local severe droughts and floods in recent years, according to the report, which instead laid the blame on extreme weather conditions caused by abnormal atmospheric circulation and air temperature mainly incurred by changes in ocean temperature and snow conditions at the Qinghai-Tibet Plateau,” says the article, published on Friday.

The results of the study were the first to be published since controversy over the dam has grown this year. Critics of the dam and some Chinese news organisations raised questions about whether the dam had worsened the effects of a drought that hit the Yangtze River region of central and southern China. The Three Gorges Dam stands in the middle of the Yangtze River.

. November 29, 2011 at 1:18 pm

Mr Verghese points out that the Tsangpo/Brahmaputra falls 2,450 metres (8,000 feet) over a few kilometres in China just before it reaches the Indian border. Send it through a 100km tunnel from the Tibetan plateau down to Assam and an enormous 54,000MW could be generated. One day its power could light not only much of north-east India and Bangladesh, but nearby Myanmar and beyond. Such a mega-structure would become a keystone for regional co-operation.

. November 29, 2011 at 9:07 pm

Google Earth Shows How Dams Could Worsen Climate Change

A project of two NGOs highlights far-ranging effects of damming rivers.

A new interactive Google Earth video tour aims to teach people how damming rivers around the world can exacerbate climate change.

The video, created by the nonprofit conservation groups International Rivers and Friends of the Earth International, is narrated by Nigerian environmental activist Nnimmo Bassey and will debut at the United Nations COP 17 Climate Change Conference in Durban, South Africa, this week.

. November 29, 2011 at 9:12 pm
. January 19, 2012 at 8:30 pm

A study by an environmental group suggests the federal government may be underestimating greenhouse gas emissions from hydro developments by a factor of 20.

The Global Forest Watch report concludes that while hydro electricity releases much less carbon than power generated by fossil fuels, emerging research suggests the difference isn’t as great as previously thought.

“The Canadian government ends up with one number and everybody assumes that must be the correct number,” said organization spokesman Peter Lee. “Instead, there’s a range of other possible, much higher, emissions based on the science.”

Hydro developments release greenhouse gases when forests and plant materials are submerged by new reservoirs. As the organic material decays, the carbon stored in it is released.

The federal government, using procedures recommended by the Intergovernmental Panel on Climate Change, has reported that such emissions total 0.5 megatonnes of carbon dioxide a year.

But Lee’s team, based on research on hydro developments in Quebec, suggests the real total is anywhere between seven and 13 megatonnes of carbon dioxide. Most of that is released in Quebec.

. March 2, 2012 at 6:58 pm

Damming the Mekong
In suspension
Further delays to a planned giant dam in Laos

THE fast-flowing currents and rich biodiversity of the Mekong river have gained a temporary reprieve. A meeting in December of the Mekong River Commission (MRC) has once again withheld approval for a controversial dam at Xayaburi in northern Laos. In a joint statement the four members of the MRC—Cambodia, Laos, Thailand and Vietnam—called for further studies on the dam’s impact on the lower Mekong. (Until now the river has not been dammed outside China—see map.) The MRC said it would ask Japan to help conduct the research.

The decision to postpone construction has been applauded by many environmental groups. They argue that, if the dam goes ahead, it will devastate ecosystems and pose a threat to fisheries, food security and the livelihoods of 65m people. What is more, a positive decision could also have given the go-ahead to eight other dam projects in Laos, and two in Cambodia. All are subject to the MRC consultation process, which is designed to improve dialogue among the riparian countries as well as the management of the river. But Philip Hirsch, a Mekong specialist at the University of Sydney in Australia, says that the decision to postpone Xayaburi has broader implications. “If they [pro-dam interests] get Xayaburi, they will probably get the lot,” he suggests.

. April 1, 2012 at 5:46 pm

Lower Churchill project gets environmental green light
Ottawa, N.L. conclude that benefits of Muskrat Falls hydro outweigh potential risks

. April 1, 2012 at 5:47 pm

The benefits of a proposed $6.3-billion hydroelectricity project in Labrador far outweigh the risks, according to the federal government.

The Canadian Environmental Assessment Agency (CEAA) gave the Muskrat Falls project a green light on Thursday on the heels of a report from a joint federal-provincial panel that warned the plant will endanger fish, wetland, caribou, fishing and sealing industries and local culture.

The federal government reviewed the panel’s report and announced its approval for Muskrat Falls on Thursday, in a move Intergovernmental Affairs Minister Peter Penashue called “an important step toward realizing the full potential of one of North America’s most ambitious renewable energy projects.”

The provincial government welcomed the news.

“Today’s release from the environmental assessment process represents another important milestone and a major step forward as we move towards our decision on final project sanction of Muskrat Falls,” Natural Resources Minister Jerome Kennedy said. “Development of the Muskrat Falls hydroelectric project will result in countless benefits to our province, the most important being the provision of reliable, least-cost power to meet the growing demand for electricity.”

Premier Kathy Dunderdale won the provincial election on a platform to build the hydroelectricty project, which aims to generate energy at Muskrat Falls on the Lower Churchill River in Labrador and is supposed to help the province handle expected increases in energy consumption.

. June 17, 2012 at 5:45 pm

Greenhouse-gas emissions from tropical dams


Emissions from tropical hydropower are often underestimated and can exceed those of fossil fuel for decades.

Tropical hydroelectric dams, such as those in Amazonia, emit significant amounts of greenhouse gases, especially methane1, 2, 3, 4. These emissions have been underestimated or ignored in many global and national greenhouse-gas accounts. If any justification is given for omitting all or part of these emissions, it is usually that they are controversial, uncertain or with no consensus5. However, although uncertainty regarding the quantities emitted is substantial6, dam emissions need to be included in all accounting based on the best available data and calculation methods. Much of the wide variation in the emissions ascribed to tropical dams stems from omissions and errors in accounting, rather than from the physical measurements that are nevertheless also subject to methodological problems.

The fact that substantial emissions are involved can hardly be considered uncertain, having been measured directly at reservoirs such as Balbina in Brazil2 and Petit Saut in French Guiana1. Dam emissions are of two types: reservoir surface or upstream emissions and those from the water that passes through the turbines and spillways (degassing or downstream emissions). Where dam emissions are counted, they often include only the upstream emissions, as in estimates by Centrais Elétricas Brasileiras S.A. (Eletrobrás)7. The recent Intergovernmental Panel on Climate Change special report on renewable energy reviews life-cycle assessments for various technologies and, for the typical case (the 50th percentile), ranks hydro as having half the impact or less compared with any other source including solar, wind and ocean energy5. The basis in data used for this optimistic classification is unclear from the report.

Carbon that is emitted as carbon dioxide can come from two types of source. First, there are fixed sources that produce a one-time emission, such as the trees killed by flooding the reservoir and the stocks of carbon in the soil (Fig. 1). Second, there are renewable sources such as the carbon that is removed from the atmosphere through photosynthesis by aquatic plants, phytoplankton or algae in the reservoir, trees in the watershed that produce litter that is washed into the reservoir by rainwater, or vegetation in the drawdown zone (the area that is temporarily exposed each time the water level is lowered in the reservoir).

. May 9, 2013 at 11:39 am

World Bank turns to hydropower to square development with climate change

The World Bank is making a major push to develop large-scale hydropower projects around the globe, something it had all but abandoned a decade ago but now sees as crucial to resolving the tension between economic development and the drive to tame carbon use.

Major hydropower projects in Congo, Zambia, Nepal and elsewhere — all of a scale dubbed “transformational” to the regions involved — are a focus of the bank’s fundraising drive among wealthy nations. Bank lending for hydropower has scaled up steadily in recent years, and officials expect the trend to continue amid a worldwide boom in water-fueled electricity.

. June 15, 2013 at 11:32 pm

Dams in the Amazon
The rights and wrongs of Belo Monte
Having spent heavily to make the world’s third-biggest hydroelectric project greener, Brazil risks getting a poor return on its $14 billion investment

THE biggest building site in Brazil is neither in the concrete jungle of São Paulo nor in beachside Rio de Janeiro, which is being revamped to host the 2016 Olympics. It lies 3,000km (1,900 miles) north in the state of Pará, deep in the Amazon basin. Some 20,000 labourers are working around the clock at Belo Monte on the Xingu river, the biggest hydropower plant under construction anywhere. When complete, its installed capacity, or theoretical maximum output, of 11,233MW will make it the world’s third-largest, behind China’s Three Gorges and Itaipu, on the border between Brazil and Paraguay.

But visit the site and Belo Monte now looks both unstoppable and much less damaging to the environment than some of its foes claim. The project has made it through Brazil’s labyrinth of planning and environmental rules. Norte Energia has hired a second consortium comprising a roll-call of Brazil’s big construction companies, which expects to finish work by 2019. Protected by a temporary cofferdam holding back the river’s flow, labourers are digging a 20km canal to funnel water from the river to the site of the main power plant, where dozens of excavators are digging down through 70 metres of rock.

But many dams were worth it (though the losers rarely received fair compensation). Itaipu, built in the 1970s by Brazil’s military government, destroyed some of the world’s loveliest waterfalls, flooded 1,350 square km and displaced 10,000 families. But it now supplies 17% of Brazil’s electricity and 73% of Paraguay’s. It is highly efficient, producing more energy than the Three Gorges, despite being smaller.

. July 2, 2013 at 2:21 pm

Perspectives on dams

SIR – Regarding your article on the Amaila Falls hydropower project (“Shrouded in secrecy”, May 4th), our projection of the likely benefits shows that it will increase Guyana’s power generation capacity by 50%. It will also enable Guyana to avoid $200m in fuel imports each year and bring $3.5 billion in savings for consumers over 20 years, before ownership of the plant is transferred to the people of Guyana.

It is predominantly funded by the private sector. The government’s main financial contribution is twofold: paying for an access road and investing $80m in equity, which will be sourced from payments for forest-carbon services that Guyana has earned under its partnership with Norway.

Amaila is the flagship of Guyana’s low-carbon development strategy, which aims to make us one of the greenest economies in the world before 2017, while maintaining 99.5% of our forests. We will reduce our greenhouse-gas emissions from electricity generation by up to 92%, which is more than for any country in the European Union.

Rather than shroud this project in secrecy, we are proud to highlight it as an example of how developing countries can lead the world towards green growth and combating climate change.

Kapil Mohabir
Office of the President
Georgetown, Guyana  

SIR – Your report on the Belo Monte dam concluded that Brazil risks getting a poor return on its $14 billion investment (“The rights and wrongs of Belo Monte”, May 4th). In fact, the return may be even worse because of the dependence of Amazon rainfall on forests. You were right to point out that the extreme seasonality of the Xingu river’s water flow will allow only 40% of the plant’s electricity-generating potential to be realised. But in a recent study in the Proceedings of the National Academy of Sciences we found that up to 3,000MW of electricity is a more likely figure than the 4,500MW cited in your article if forests continue to be cleared.

Given the importance of hydroelectric power from the Amazon’s tributaries to Brazil’s energy strategy, it would behove decision-makers to think of securing and deepening Brazil’s progress in curbing deforestation as a matter of national energy security.

Claudia Stickler
Scientist with the international programme of the Amazon Environmental Research Institute
San Francisco

. October 7, 2013 at 2:54 pm

The great rivers of China are being dammed, regardless of the consequences

Yet it does not matter how strong the case may be against Xiaonanhai, because the battle against a hydropower scheme in China is usually lost before it is fought. The political economy of dam-building is rigged. Though the Chinese authorities have made much progress in evaluating the social and environmental impact of dams, the emphasis is still on building them, even when mitigating the damage would be hard. Critics have called it the “hydro-industrial complex”: China has armies of water engineers (including Hu Jintao, the former president) and at least 300 gigawatts of untapped hydroelectric potential. China’s total generating capacity in 2012 was 1,145GW, of which 758GW came from coal-burning plants.

“Hydro, including large hydro in China, is seen as green,” says Darrin Magee, an expert on Chinese dams at Hobart and William Smith Colleges in New York state.

The most controversial emblem of Chinese hydropower is the Three Gorges dam, the largest in the world with a capacity of 22.5GW. In contrast, America’s Hoover Dam has less than one-tenth of that capacity. Many critics within China felt that the Three Gorges was too big and too dangerous to build. They predicted that silt would collect in its reservoir, threatening the stability of the dam and lessening its capacity to produce power. They warned that the dam’s vast reservoir, which would submerge the homes of more than 1m people, would become polluted and alter the flow and ecology of the Yangzi river. They also feared that the dam could cause earthquakes, as it sits on two major fault-lines.

In the end, though, political power trumped scientific argument. Nearly one-third of China’s legislature either abstained or voted against the Three Gorges dam in 1992, in what remains the most vocal opposition the rubber-stamp body has ever registered against a proposal from China’s leaders. But Li Peng, then prime minister, had trained as a hydroelectric engineer and was determined to build the dam. (His daughter, Li Xiaolin, is head of a publicly listed arm of one of the five big state-owned power companies.)

. September 29, 2014 at 5:56 pm

Energy from dams and other hydroelectric sources avoided 2.8 billion tonnes [of carbon dioxide] (though emissions of methane from the reservoirs behind some of those dams mean the net effects were less than that).


. February 20, 2016 at 12:06 am

The Mekong river
Damned if you do
Governments should stop building dams on the mother of rivers

. February 20, 2016 at 12:09 am

The Mekong region is Asia’s rice bowl: in 2014 lower Mekong countries (Myanmar, Laos, Cambodia, Thailand and Vietnam) produced more than 100m tonnes of rice, around 15% of the world’s total. The region’s fertile soil depends on nutrient-rich sediment that the Mekong carries downriver, mainly during the rainy season from June to October; more than half the sediment in central Cambodia comes from China. The river and the nutrients it brings also support the world’s biggest inland fishery, accounting for a quarter of the global freshwater catch, feeding tens of millions of people.

The region boasts remarkable biodiversity; only the vast basins of the Congo and the Amazon compare to or surpass it. There are more than 20,000 types of plant and nearly 2,500 animal species; freshwater dolphins and giant catfish; spiders 30 centimetres across and, in a limestone cavern in Thailand, a day-glo pink, cyanide-secreting millipede. The human diversity is striking, too: Tibetan monks pray; Burmese traders buy and sell; Cambodian fishermen cast nets; Thai farmers reap; Vietnamese markets float. The history is as rich as the soil. The Buddha smiled while resting at the northern Lao city of Luang Prabang. Angkor Wat on the Mekong-fed Tonle Sap lake was among the biggest cities of the preindustrial world. The Khmer empire that built it dominated South-East Asia for longer than there have been Europeans in the Americas.

Since its French colonial days the Mekong has been more of a backwater. But the life-changing development seen elsewhere in Asia is spreading into this mostly rural world. Pickup trucks are replacing bullock-carts, karaoke bars dot lonely two-lane roads, fishermen can catch up on soap-operas at night. People are getting richer, and their lives longer.

And as modernity comes into the region, it also seeks to take something out. Countries see a new resource in the Mekong: not the support it offers rich networks of life, but the simple fact of its flow. The hydroelectric dams now built on and planned for the Mekong amount to one of the largest-ever interventions in a river’s course. As its currents are rechannelled down copper conduits to power far-off cities the river itself will be trapped behind a series of concrete walls. Its fisheries, agriculture and biodiversity will suffer; the lives lived on its banks will be reshaped with scant regard for the feelings of those who lead them.


. February 20, 2016 at 12:09 am

“But that is about to change. A little way downriver, a state-owned power utility is building the 990-megawatt Wunonglong dam. In 1995 the Manwan dam, some 600km farther downstream, became the first to stem the river’s flow. Since then five more dams have been finished along its Chinese reach; the Wunonglong dam is one of a further 14 being planned or built there.

China’s Communist Party has long been keen on dams. At least 86,000 have been built over the past six decades, providing 282 gigawatts (GW) of installed hydroelectric capacity by 2014. The government is building yet more to curb the country’s greenhouse-gas emissions. By 2020 it wants an astonishing 350GW of installed hydropower capacity; in the European Union that would be enough to meet about three-quarters of total electricity needs. The dam at Wunonglong, about 300 metres long and more than 100 metres high, will provide a smidgen less than one of those extra gigawatts. The other 13 are expected to add 15.1GW more. “

. February 20, 2016 at 1:02 am

“Environmental groups warn that by turning a free-flowing river into a series of reservoirs the upstream Lao dams could wipe out the Mekong’s two largest freshwater species: the giant catfish and the giant pangasius. Similar warnings have been raised about the Don Sahong dam—which would span the Mekong across the breathtakingly beautiful Si Phan Don (Four Thousand Islands) region near Laos’s border with Cambodia—and about Cambodia’s giant Sambor dam, which may destroy one of the last remaining habitats of the Irrawaddy dolphin.

The Xayaburi dam’s builders have redesigned its sluice gates to allow more nutrient-rich sediment to flow downstream, and widened its fish pass to accommodate more fish of different species. The Lao government says these tweaks will alleviate the worst harms. Environmentalists are less certain. Fish passes in dams have been repeatedly found not to live up to promises made for them, particularly when fish must pass through multiple sets, as they would if Laos builds all its planned dams.

The Mekong might survive a few big mainstream dams, but a dozen—plus dozens more on its tributaries—present a qualitatively different sort of threat. This highlights a recurring theme of Mekong development: dam-builders tend to assess the impact of each dam individually; NGOs pay more attention to the cumulative effect of multiple dams. The NGOs also worry that with every new dam built, further dam-building becomes more normal, and the next project thus becomes easier to justify.

Environmentalists think both that such synergies make the harm done by dams greater than governments claim, and that the benefits are overestimated. Touting hydropower as “green” because it can be used in the place of fossil-fuel derived electricity overlooks external costs such as compensation and relocation, lost agricultural productivity and biodiversity and lowered water quality. And although benefits may be large (especially for electricity exporters), they are hardly overwhelming, especially in the context of broader development. Power demand in the region is expected to more than double between now and 2025—having already doubled from 2005. According to Richard Cronin, a Mekong specialist at the Stimson Centre, an American think-tank, the nine Lao and two Cambodian dams currently discussed would provide just 6-8% of the total electricity needs of the lower Mekong basin by 2030, with most of the power going to Thailand. “For that,” Mr Cronin asks, “you’re going to kill the river?” “

. August 15, 2017 at 12:43 pm

A LOT depends on the convoys of lorries now rumbling through the rugged interior of Labrador in eastern Canada. They are carrying equipment to be installed at Muskrat Falls, a hydroelectric project on the Churchill River. The 824MW dam, scheduled to begin operation in 2020, is supposed to reduce Newfoundland and Labrador’s dependence on fossil fuels and produce a surplus for sale to neighbouring Nova Scotia. But it is shaping up to be the latest in a long series of failed schemes to improve the economy of Canada’s slowest-growing province.

In June the provincial government revealed that the project, including a transmission line to Newfoundland, would cost C$12.7bn ($10bn) to build, more than double the original estimate of C$5bn. To pay for that, electricity rates will nearly double to 23.3 cents per kilowatt hour by 2022, twice what Canadians now pay on average. Indigenous groups that live near the dam and other people downstream worry that rotting vegetation in the reservoir will release mercury and that the construction convoys will damage roads. Three Inuit protesters were arrested in July for blocking the lorries.

Churchill Falls, upriver from and much bigger than Muskrat Falls, is the biggest nightmare. A private firm, the British Newfoundland Development Corporation, built it on time and on budget and sold it in 1974 to the province’s government. The problem is the contract that the government signed with its neighbour, Quebec. It obliges Newfoundland and Labrador to sell electricity at C$2 per MWh, a fraction of its current market price, until 2041. The arrangement, which Newfoundland and Labrador agreed to in part because Quebec was the nearest customer, will yield a profit of C$26bn for Quebec’s government, which sells electricity to the United States. Newfoundland and Labrador will pocket just C$2bn over the life of the project. The province has tried repeatedly to break the deal in court and lost every time. Canada’s Supreme Court will hear an appeal, the third to the highest court on various aspects of the dispute, later this year.

Muskrat Falls is the latest attempt to diversify out of commodities and jump free from the “geographical stranglehold of Quebec”, in the words of Danny Williams, the Conservative premier who authorised the project in 2010. A transmission line now being laid under the Cabot Strait will carry some of the surplus to Nova Scotia, bypassing the French-speaking province. Then it will pay off, Mr Williams insists.

Critics say that the former premier ignored cheaper options for producing power. Dwight Ball, his Liberal successor, calls Muskrat Falls “ill-conceived and reckless” and promises to conduct a forensic audit after it opens. “There’s a lot of lessons to be learned from the way [Newfoundland and Labrador] went about this,” says Dennis Browne, the province’s consumer advocate. He thinks it will learn from its mistakes. History suggests otherwise.

. August 22, 2017 at 5:28 pm

That turns out not to have been the case. The pool was deemed by Egypt to be a result of construction and seasonal Nile flooding. But the alarms it raised are indicative of how sensitive negotiations between Egypt, Ethiopia and Sudan have become. Talks over such things as how fast to fill the reservoir and how to operate the dam have stumbled. And a potentially huge complication looms over any discussion of the Nile’s future: climate change.

By 2050 around a billion people will live in the countries through which the Nile and its tributaries flow. That alone will put enormous stress on the water supply. But according to a study by Mohamed Siam and Elfatih Eltahir of MIT, potential changes to the river’s flow, resulting from climate change, may add to the strain. Messrs Siam and Eltahir conclude that on current trends the annual flow could increase, on average, by up to 15%. That may seem like a good thing, but it could also grow more variable, by 50%. In other words, there would be more (and worse) floods and droughts.

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