Tag Archives: dams dry spells

Choking the Water: Dams, Dams and More Dams

Since Tibet is part of China, Chinese engineers have been making the most of that potential. They have built big dams not only on rivers like the Yellow and the Yangzi, which flow across China to the Pacific, but also on others, like the Brahmaputra and the Mekong, which pass through several more countries on their way to the sea.

China has every right to do so. Countries lucky enough to control the sources of big rivers often make use of the water for hydropower or irrigation before it sloshes away across a border. But If the countries nearest the source of water, like China,  suck up too much of the flow, or even simply stop silt flowing down or fish swimming up by building dams, the consequences in the lower reaches of the river can be grim: parched crops, collapsed fisheries, salty farmland.

Tension and recrimination have been the order of the day for China and its neighbours… In part, this is because a river like the Mekong does not contain enough water to go round. China has already built 11 dams across the main river (never mind its tributaries) and has plans for eight more; the downstream states have built two and are contemplating seven more. Last year, during a drought, the river ran so low that Cambodia had to turn off a big hydropower plant. Even when rainfall is normal, the altered flow and diminished siltation are causing saltwater to intrude into the Mekong delta, which is the breadbasket of Vietnam, and depleting the fish stocks that provide the only protein for millions of poor Cambodians.

China has long resisted any formal commitment to curb its construction of dams or to guarantee downstream countries a minimum allocation of water. It will not even join the Mekong River Commission, a body intended to help riparian countries resolve water-sharing disputes…

China has not signed any agreements about managing the Mekong with the other countries it flows through, so is not obliged to share a particular amount of water with them, nor even provide data on the flow or any warning about the operations of its dams. It does provide the Mekong River Commission with a trickle of information about water levels and planned releases from dams, which helps with flood-control lower down the river

Excerps from Water Torture: Hydropower in Asia, Economist, May 16, 2020; Torrent to Tickle: the Mekong, Economist, May 16, 2020

Dams and Drought: the Amazon

The São Luiz do Tapajós (SLT) project… would dam one of the last big unobstructed tributaries of the Amazon. The project would provide about a third of the hydropower that Brazil plans for the forthcoming decade, but it would also flood 376 square km (145 square miles) of land where the Munduruku hunt, fish and farm. “The Tapajós valley is our supermarket, our church, our office, our school, our home, our life,” explained Mr Kabá.

The tussle over the Tapajós dam is part of a bigger fight about Brazil’s energy future. SLT is an example of a new sort of hydropower project, which floods a smaller area than traditional dams and therefore ought to cause less disruption and environmental damage. The massive Itaipu dam on the border with Paraguay inundated an area nearly four times as large. But critics of hydropower say “run of river” projects like SLT, which use a river’s natural flow to turn turbines, do not work as well as advertised. Though less destructive than conventional dams, which require bigger reservoirs, they still provoke opposition from people like the Munduruku. Other energy sources, such as gas and wind, are becoming more competitive. Brazil has “an opportunity” to rethink its energy policies, says Paulo Pedrosa, an energy official.

Hydropower has long been Brazil’s main way of generating electricity. Most forecasts suggest it will remain so. The government intends to build more than 30 dams in the Amazon over the next three decades. 

Climate change may worsen the problem. Some climate models predict that river flows in large parts of the Amazon will fall by 30% in coming decades. Deforestation is delaying the onset of the rainy season in some areas by six days a decade, according to research published in Global Change Biology, a journal.   Drought can be expensive. In 2014 power from conventional dams dipped because of a dry spell, forcing electricity companies to buy from gas- and coal-powered generators at high spot prices. The risk of such fluctuations rises with run-of-river dams. Carlos Nobre, a former chief of research at the ministry of science, technology and innovation, thinks more frequent droughts will make future hydropower projects in the Amazon unprofitable.

Brazil’s potential for solar and wind energy is among the highest in the world. The government has promoted them with lavish tax breaks. In the blustery north-east, wind power overtook hydropower this year; wind turbines now generate 36% of the region’s electricity, up from 22% in 2015. The Energy Research Company, a firm linked to the energy ministry, expects renewable generating capacity apart from hydropower to double by 2024.

Generators fuelled by natural gas have been hurt by the subsidies lavished on renewable energy. But, though less climate-friendly than hydropower, they are beginning to compete with it as a source of steady baseload electricity. Brazil now produces gas in abundance as a by-product of pumping oil from its offshore wells. Its marginal cost of production is nearly zero. The future of baseload energy is “hydro-thermal”, rather than hydro alone, says Adriano Pires of the Brazilian Infrastructure Centre, a think-tank in Rio de Janeiro.

Excerpts from Dams in the Amazon: Not in my valley, Economist,  Nov. 5, 2016

Blackstone, China, Secrecy: Guyana

The government of Guyana wants to move forward with an $840m project at Amaila Falls, deep in the forested interior. At full capacity of 165MW, it could supply more power than Guyana’s present needs.  The lead developer is Sithe Global, part of the Blackstone Group. Sithe wants a guaranteed 19% return on its equity stake, and plans to start construction this year. China Railway First Group signed an engineering contract in September. The China Development Bank will lend most of the money. The Inter-American Development Bank has been asked to chip in $175m; the World Bank was initially involved, but has pulled out.

Amaila’s supporters point out that it will flood less than 55 square km (21 square miles). No villages will be displaced and little wildlife will be disturbed. Guyana would no longer rely on fossil fuels for electricity. After two decades, ownership would pass to the government, construction costs paid off.

Opponents worry that clean electricity will not come cheap. Guyana Power and Light (GPL), the state-owned electricity company, will pay about $100m a year to the Amaila consortium. Electricity bills are unlikely to fall (three people were killed last year in protests over electricity charges). And Amaila’s power may not be reliable. The El Niño weather pattern can bring a year-long drought. In normal years, the plant will run below capacity between October and April. GPL will have to pay for backup thermal power. The IMF has urged “careful consideration of the [financial] risks”.

Plans to build Amaila date from 1997, though Sithe only got involved in 2009. The estimated cost has risen steadily. An access road is unfinished. There is as yet no economic feasibility study for the project; when completed, the study will remain confidential, as is GPL’s outline power-purchase agreement. Opposition parties complain that the government is being “secretive” about Amaila. On April 24th they blocked funds for a government equity-stake in the project. If Amaila is as beneficial as its backers claim, an open debate might generate broader support for the project, and cut its $56m bill for political risk insurance.

Hydropower in Guyana: Shrouded in secrecy, Economist, May, 4, 2013, at 39