6.6.23
Samuel Schlaefli
The expansion of hydropower generation often leads to conflicts of interest, both in Switzerland and beyond. Researchers from ETH Zürich are trying to find a basis for compromise that serves the public interest.
The Gibe III Dam on the Omo River in Ethiopia (2016). (Photograph: Wikimedia Commons / Mimi Abebayehu)
Without hydroelectric power, Switzerland would be a shadow of what it is today. The country generates some 60 percent of its electricity from a nationwide network of 1,500 run-of-river and “storage hydropower plants” – and their importance is only going to grow. “By 2050, electricity will make up between 38 and 46 percent of Switzerland’s energy mix, which is a considerable jump from today’s figure of 27 percent,” says Robert Boes, Professor of Hydraulic Engineering at ETH Zürich. That’s because a successful transition to renewables means replacing fossil fuels and electrifying more energy uses such as private transport. At the same time, Switzerland’s last nuclear power plant is due to shut down in about ten years – so solar, wind and hydro will have to pick up the slack. The advantage of storage hydropower plants is their ability to store large amounts of energy over long periods of time, which is particularly important in winter when sunlight is less plentiful.
Expand and build
“The fact that Switzerland can use water to store energy is a huge help when it comes to transitioning to a low carbon economy,” says Boes. Over the past few years, his research group has carried out extensive research into the potential for expanding reservoirs in Switzerland and building new ones. In 2020, they calculated how much additional power could be produced if the capacity of 38 existing reservoirs in the Swiss Alps – each with a usable volume of at least 20 million cubic metres of water – were increased by 5, 10 or 20 percent. The researchers evaluated each reservoir’s potential on the basis of eight criteria, including impacts on conservation areas and existing infrastructure and the ability to shift power generation to the critical winter period. They concluded that it would be possible to shift an additional 2.2 to 2.9 terawatt-hours (TWh) of electricity from summer to winter each year by expanding anywhere between 17 and 26 of the reservoirs on their list. Total winter hydropower generation would then rise from the current figure of 48 percent to as much as 62 percent of total annual hydropower production.
Boes’ group also calculated the potential of constructing new reservoirs in 62 previously identified areas where glaciers are retreating. These areas, which were once home to large bodies of ice, will soon turn into natural lakes or empty expanses that can be used for reservoirs. “Within just ten years, for example, the Trift Glacier in the canton of Bern has retreated to such an extent that the lake could already be used to generate electricity,” says Boes. Existing infrastructure tends to be minimal in the vicinity of newly formed glacial lakes, and in most cases, the areas freed from the ice are not protected. Boes’ analysis came up with new hydro plants at the 12 most suitable locations after factoring in biotopes of national importance. These could produce between 1 and 1.2 TWh of electricity a year through natural flow and add a storage capacity of 1.4 to 1.5 TWh, taking into account existing plants in the downstream hydropower cascades.
The studies carried out by Boes’ research group were high on the agenda of the Swiss government’s Hydropower Round Table in August 2020, which brought together environmental organisations, hydro plant operators and cantonal and federal authorities. The participants discussed how to meet the goal of increasing winter power generation by 2 TWh by 2040, ultimately agreeing on a proposal to expand eleven existing reservoirs – including the Grimsel reservoir in the canton of Bern and Mattmark lake in the canton of Valais – and create four new ones. “At the core of the strategy is a potential reservoir near the Gorner Glacier, which could increase storage capacity by 650 gigawatt hours and annual generation by 200 gigawatt hours of energy a year,” says Boes. “But building new reservoirs is a lot more controversial than expanding existing ones.” Indeed, the Gorner proposal attracted plenty of criticism at the Round Table, with the Swiss Landscape Conservation Foundation refusing to sign the final declaration. One of their chief complaints was that the creation of the Gorner reservoir would have far-reaching consequences for one of the last unspoiled glacial mountains, which is listed in the Swiss Federal Inventory of Landscapes and Natural Monuments of National Importance. This is yet another example of how the expansion of hydropower always provokes conflicts of interest – however useful it may be as a mitigation strategy against climate change.
Balancing conflicting interests
Someone who has spent years grappling with such conflicts of interest is Paolo Burlando, Professor of Hydrology and Water Resources Management at ETH Zürich. “Hydropower projects inevitably cause river fragmentation, which in turn has an impact on local ecosystems,” he says. He cites an example from his own research in Zambia’s Kafue Flats, a 240-kilometre-long and 50-kilometre-wide floodplain made up of swamp, open lagoon and seasonally inundated areas. During the rainy season, the floodplain receives water from the Kafue River, a tributary of the Zambezi River. It is an important habitat for antelope, zebras and hippos, as well as 450 endangered species of bird. Yet since the construction of two large dams in the 1970s, the frequency of flooding has diminished, with a correspondingly negative impact on biodiversity. So how do you weigh the need to generate power against the importance of protecting ecosystems?
To help answer such questions, Burlando and his team are devising mathematical models to facilitate a participatory and integrated management of water resources. Their hope is that simulating scenarios and providing a quantitative assessment of impacts could help to reduce conflicts between nature conservation, electricity production, the use of water for agricultural purposes and the exploitation of water for industrial activities. The EU’s DAFNE project proved to be a perfect opportunity to put the models to the test: with the help of 13 research partners from Europe and Africa – as well as regional authorities and hydropower plant operators – Burlando was able to apply one of his models to two concrete case studies: the drainage basin of the Zambezi River in southern Africa and that of the Omo-Turkana River basin on the Ethiopia-Kenya border. Key variables used in the model included the revenues of hydropower companies and the security of the electricity supply, the amount of water available for agricultural use, the devitations from the natural flooding of fragile ecosystems and the implications for the availability of drinking water. The simulations also addressed the expected impact of climate change. In the case of the Zambezi, the researchers were able to show that electricity production could be increased by 20 percent simply by improving coordination between the countries’ dam operators – without any additional negative impact on the ecosystems.
For the second case study in the Omo-Turkana basin, the DAFNE team turned their attention to a complex political situation. Ethiopia has built three dams on the Omo River in recent years and has planned to use the water for large-scale sugar cane cultivation in the southern regions of the basin. The Omo is the only major river that feeds Lake Turkana. Located almost entirely within Kenya’s borders, the lake is a lifeline for thousands of nomads and their livestock. “According to our models, electricity production in Ethiopia will not restrict water availability in Kenya in the long term; at most, it will affect the temporal variability of the streamflow regime,” says Burlando. “But the extraction of water for extensive irrigation poses a far greater threat.” Energy production only requires the water to be stored and then channelled through turbines. This alters the natural course of the river by fragmenting it and modifying the natural flow regime, thus impacting aquatic ecosystems, but it has no effect on the total amount of water. A liaison at the institutional level is not yet on the agenda, and the conflict remains politically and technically unresolved. “But at least we got technical experts from Ethiopia and Kenya sitting at the same table and discussing concrete management scenarios and solutions for conflicting uses,” concludes Burlando.
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The Swiss Federal Institute of Technology in Zürich [ETH Zürich] [Eidgenössische Technische Hochschule Zürich] (CH) is a public research university in the city of Zürich, Switzerland. Founded by the Swiss Federal Government in 1854 with the stated mission to educate engineers and scientists, the school focuses exclusively on science, technology, engineering and mathematics. Like its sister institution The Swiss Federal Institute of Technology in Lausanne [EPFL-École Polytechnique Fédérale de Lausanne](CH) , it is part of The Swiss Federal Institutes of Technology Domain (ETH Domain)) , part of the The Swiss Federal Department of Economic Affairs, Education and Research [EAER][Eidgenössisches Departement für Wirtschaft, Bildung und Forschung] [Département fédéral de l’économie, de la formation et de la recherche] (CH).
The university is an attractive destination for international students thanks to low tuition fees of 809 CHF per semester, PhD and graduate salaries that are amongst the world’s highest, and a world-class reputation in academia and industry. There are currently 22,200 students from over 120 countries, of which 4,180 are pursuing doctoral degrees. In the 2021 edition of the QS World University Rankings ETH Zürich is ranked 6th in the world and 8th by the Times Higher Education World Rankings 2020. In the 2020 QS World University Rankings by subject it is ranked 4th in the world for engineering and technology (2nd in Europe) and 1st for earth & marine science.
As of November 2019, 21 Nobel laureates, 2 Fields Medalists, 2 Pritzker Prize winners, and 1 Turing Award winner have been affiliated with the Institute, including Albert Einstein. Other notable alumni include John von Neumann and Santiago Calatrava. It is a founding member of the IDEA League and the International Alliance of Research Universities (IARU) and a member of the CESAER network.
ETH Zürich was founded on 7 February 1854 by the Swiss Confederation and began giving its first lectures on 16 October 1855 as a polytechnic institute (eidgenössische polytechnische schule) at various sites throughout the city of Zurich. It was initially composed of six faculties: architecture, civil engineering, mechanical engineering, chemistry, forestry, and an integrated department for the fields of mathematics, natural sciences, literature, and social and political sciences.
It is locally still known as Polytechnikum, or simply as Poly, derived from the original name eidgenössische polytechnische schule, which translates to “federal polytechnic school”.
ETH Zürich is a federal institute (i.e., under direct administration by the Swiss government), whereas The University of Zürich [Universität Zürich ] (CH) is a cantonal institution. The decision for a new federal university was heavily disputed at the time; the liberals pressed for a “federal university”, while the conservative forces wanted all universities to remain under cantonal control, worried that the liberals would gain more political power than they already had. In the beginning, both universities were co-located in the buildings of the University of Zürich.
From 1905 to 1908, under the presidency of Jérôme Franel, the course program of ETH Zürich was restructured to that of a real university and ETH Zürich was granted the right to award doctorates. In 1909 the first doctorates were awarded. In 1911, it was given its current name, Eidgenössische Technische Hochschule. In 1924, another reorganization structured the university in 12 departments. However, it now has 16 departments.
ETH Zürich, EPFL (Swiss Federal Institute of Technology in Lausanne) [École polytechnique fédérale de Lausanne](CH), and four associated research institutes form The Domain of the Swiss Federal Institutes of Technology (ETH Domain) [ETH-Bereich; Domaine des Écoles polytechniques fédérales] (CH) with the aim of collaborating on scientific projects.
Reputation and ranking
ETH Zürich is ranked among the top universities in the world. Typically, popular rankings place the institution as the best university in continental Europe and ETH Zürich is consistently ranked among the top 1-5 universities in Europe, and among the top 3-10 best universities of the world.
Historically, ETH Zürich has achieved its reputation particularly in the fields of chemistry, mathematics and physics. There are 32 Nobel laureates who are associated with ETH Zürich, the most recent of whom is Richard F. Heck, awarded the Nobel Prize in chemistry in 2010. Albert Einstein is perhaps its most famous alumnus.
In 2018, the QS World University Rankings placed ETH Zürich at 7th overall in the world. In 2015, ETH Zürich was ranked 5th in the world in Engineering, Science and Technology, just behind the Massachusetts Institute of Technology, Stanford University and University of Cambridge (UK). In 2015, ETH Zürich also ranked 6th in the world in Natural Sciences, and in 2016 ranked 1st in the world for Earth & Marine Sciences for the second consecutive year.
In 2016, Times Higher Education World University Rankings ranked ETH Zürich 9th overall in the world and 8th in the world in the field of Engineering & Technology, just behind the Massachusetts Institute of Technology, Stanford University, California Institute of Technology, Princeton University, University of Cambridge(UK), Imperial College London(UK) and University of Oxford(UK) .
In a comparison of Swiss universities by swissUP Ranking and in rankings published by CHE comparing the universities of German-speaking countries, ETH Zürich traditionally is ranked first in natural sciences, computer science and engineering sciences.
In the survey CHE Excellence Ranking on the quality of Western European graduate school programs in the fields of biology, chemistry, physics and mathematics, ETH Zürich was assessed as one of the three institutions to have excellent programs in all the considered fields, the other two being Imperial College London (UK) and the University of Cambridge (UK), respectively.
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