[Podcast] GigaWhat: Clean-washing by dams?

  • Hydropower is not only considered as a reliable energy source, but also ‘green and clean’ due to the lack of direct emissions. However, ecologists and activists, who study the impact of such projects on local communities and the environment, question how ‘clean’ the energy source really is.
  • Hydroelectricity forms an important part of India’s target to install 500 GW of non-fossil fuel-based capacity by 2030.
  • The Himalayas are known to have the highest density of dams in the world. But increasing flash floods and unpredictable rainfall patterns in the Himalayas raise concerns about the reliability of hydropower structures.
  • In the fifth episode of GigaWhat, we unpack the social, economic and environmental impacts of hydropower projects in India and the controversies surrounding the megastructures – dams.

Hydropower is an integral part of India’s energy mix. India has 5,334 completed large dams and 411 under-construction large dams. By 2029-30, India aims to develop 70 large hydropower projects with a total installed capacity of about 30 GW. India also recognises large and small hydropower as renewable and a clean energy source.

However, activists and researchers who have been working on issues related to the displacement of communities due to dam construction, and ecologists who study the impacts of dams on aquatic species and the region’s biodiversity, think otherwise. They opine that the terms’ clean’ and ‘green’ used to describe hydropower could be misleading, as it does not consider the livelihoods lost and the cost of biodiversity lost at stake.

In this episode of GigaWhat, Mongabay-India Contributing Editor and the podcast host, Mayank Aggarwal, speaks with experts to understand if hydropower is actually a clean energy source or simply a clean-washing attempt.

Ammu Susanna Jacob (Research Scientist at CSTEP), Shishir Rao (engineer-turned-ecologist currently with the University of Georgia) and Prakash Bhandari (environmental researcher and activist from Himdhara, Environment Research and Action Collective) discuss how we should be analysing the controversies surrounding dams in the country and the possible first steps to improve the hydropower sector.

Listen here:



Full transcript

You are listening to Everything Environment by Mongabay-India.

Mayank Aggarwal (MA): A dam is proposed on the Tons river at the border of two Himalayan states – Himachal Pradesh and Uttarakhand. Once built, it could be among India’s tallest dams. If it goes through, the Kishau hydroproject will increase India’s electricity grid’s capacity by 660 MW. But the area will lose over 80,000 trees, around 3000 hectares of land will be submerged and about 5,500 people will have to be relocated.

This is just one example. The Himalayas are known to have the highest density of dams in the world. The rivers here are punctuated by these megastructures … and many more are in the pipeline.

This level of interference with a river’s natural flow ends up changing the ecology and the lives of people dependent on the river. Over time, severe alterations in the river escalate into disasters or amplify natural disasters.

These stories surface from rivers and regions across India.

Shishir Rao (SR): Firstly, we would all agree that we certainly need dams. They are important for economic development. The question is, how many do we need then? And where do we install them, right?

MA: Hydropower has been an old and reliable source of energy in India. It has also irrigated the country’s fields. While much discussed, over the years, gas and nuclear-based energy projects have not emerged to be viable options for India. Hydropower, on the other hand, finds itself placed on a pedestal. It is not only considered a reliable energy source but also ‘green and clean’ due to the lack of direct emissions. At the same time, it is considered ‘renewable and sustainable’ because of the assumption that water is a never-ending resource.

Until a few years ago, India considered a hydropower project renewable only when the installed capacity was less than 25 megawatt (MW). But then, in 2019, the government of India decided to consider large hydropower projects as renewable projects too. This makes hydroelectricity an important part of India’s clean energy targets – installing 500 gigawatt (GW) of non-fossil fuel-based capacity by 2030.

Ammu Susanna Jacob (ASJ): For a low carbon energy mix, hydropower will be the backbone and this is mainly because hydropower is a flexible resource.

MA: In this episode, we’ll hear about how dams are perceived as a more stable source of energy when compared to solar and wind, which are less reliable owing to the absence of advanced storage technologies for energy from these sources. We’ll also hear about the true cost of relying on this form of energy. Our conversations raise a contentious question – can hydropower truly be considered clean and renewable? Or is it simply a case of clean-washing?

SR: I think we need to think deeply about what these terms mean – clean, renewable, green, right? I think the term renewable in the case of hydropower is slightly misleading.

MA: I’m Mayank Aggarwal, Contributing Editor at Mongabay-India. We are an online publication dedicated to bringing you stories on science and the environment in India.

In our special podcast series, GigaWhat, we’ll explore some of the biggest questions, challenges, and opportunities in India’s transition from fossil fuels to clean energy sources.

ASJ: If we look into also the world energy mix, we find that hydropower has the largest share, even when solar and wind and nuclear are put together.

MA: Ammu Susanna Jacob is a Research Scientist at The Center for Study of Science, Technology and Policy, also known as CSTEP. She works on energy storage systems and grid integration of renewables.

ASJ: So, this is very old technology. It is a flexible technology, and it is not going to replace solar and wind; it will go hand in hand. We need solar and wind as well as large hydro in the power grid because that’s how we will be able to meet our energy demand.

Currently, we have around 23 percent of what you know as variable renewable energy resources in the grid. That means both solar and wind together.

MA: Solar and wind account for 420 GW of India’s target of 500 GW of non-fossil energy. But these technologies come with intermittency since they depend on the availability of sunlight and geography.

In this scenario, where solar and wind power cannot provide 24×7 energy, hydel becomes crucial to balance the grid.

ASJ: Now, we are planning to increase this percentage of variable renewable sources and currently, we do not have any larger energy storage systems which will take into consideration this intermittency of solar and wind. And also, we see our demand is highly dynamic. And when demand is highly dynamic, we need a resource that would be able to provide this load. Like, we have a peak load, we have an evening peak load and during that time, we need resources that are stable enough to cater to that peak load, as well as cater to those fluctuations of solar and wind. Hence, it is very important for our grid stability.

In our current energy mix, we see that the highest share is from thermal energy; around 60 percent of the energy is coming from thermal energy, mainly coal, diesel and gas. Now, India has pledged for it In COP26, India has pledged an increase of non-fossil energy sources in its energy mix. So, we had a target of around 450 gigawatt and that was revised to 500 gigawatts. So, for a low carbon energy mix, hydropower will be the backbone and this is mainly because hydropower is a flexible resource.

MA: The 2019 edition of the National Register of Large Dams says that India has 5,334 completed large dams and 411 under-construction large dams. By 2029-30, India aims to develop 70 large hydropower projects with a total installed capacity of about 30 GW. Many of these projects are in the Himalayan states such as Uttarakhand, Himachal Pradesh, Jammu and Kashmir, Arunachal Pradesh and Sikkim.

SR: I think when we started building dams, we probably did not realise or foresee that dams would have severe ecological, environmental and social impacts, right?

MA: Shishir Rao is an engineer-turned-ecologist currently with the University of Georgia in the United States. He researches tropical river ecology in the Western Ghats and studies what happens to river biodiversity when its flow is altered.

SR: So, most of the large dams were built in the USA in the 70s or 80s, when most of the large dams were built. And in the developed world, they sort of realised that there are significant impacts of dams, and the number of dams came down. But I think in India and China, the dam construction has sort of continued, although at a much slower pace.

If you look at the Narmada dam, the protests were initially about people getting displaced and the forests getting submerged. The understanding of ecological effects came slightly later, specifically regarding downstream impacts. For example, at the site of the dam, surely the forests are being submerged and there is certainly an impact on the ecology. But, as the dam continues to operate, the downstream consequences of dams become more and more obvious. So that’s where you know, the ecology comes in, like what happens when you alter the flow? And what are the sorts of changes that you see in the river in terms of its water quality in terms of habitat for fish? Overall, what happens in the watershed?

Read more: [Book review] The Narmada Bachao Andolan through the eyes of lesser-known tribal leaders

SR: We need to think deeply about what these terms mean – ‘clean,’ ‘renewable,’ and ‘green,’ right?

So, I think the hydropower energy and hydropower dams get the label of being renewable because we tend to think of water as a renewable source of energy, compared to your traditional non-renewable sources of energy where we are literally using coal. Having said that, yes, hydropower dams are renewable because water as a resource is renewable.

But, you need to look at what’s happening to the river. You are still damming the river, altering its natural flow, and impacting the ecology, regardless of how you’re using the water. So, I think the term renewable in the case of hydropower is slightly misleading. And then there’s also the connotation of it being a clean source of energy. But there are recent studies showing that large reservoirs emit greenhouse gases because, when you construct a dam, you submerge forests and all the submerged vegetation that is now under water is slowly decomposing, and it is releasing carbon dioxide and CH4 which are greenhouse gases.

MA: We spoke to Prakash Bhandari, an environmental researcher and activist from Himdhara, Environment Research and Action Collective based in Himachal Pradesh. He has closely seen the impacts of hydropower projects in the Himalayan region.

Prakash Bhandari (PB): We work as a support group for mountainous communities. Whenever the community faces problems related to natural resources or developmental projects, Himdhara intervenes and works with the people and helps them.

Today, all across the Himalayas, we know that Himachal Pradesh is the largest generator of hydropower. Around 10,500 MW of electricity is generated here. These projects are basically on five river basins – Ravi, Satluj, Vyas, Yamuna and Chenab basins. Out of these five, three basins – Ravi, Satluj and Vyas, have the highest number of hydroelectric projects on them. If we consider Sutlej or Ravi, more than 70 percent of the river is actually flowing through tunnels, or their water is stagnant behind the dam. Basically, these two rivers are dead.

Read more: A twin-state hydropower project could drown livelihoods and biodiversity

MA: One widespread form of hydropower project seen in the Himalayas are the run-of-the-river projects.

PB: The difference between large dams and run-of-the-rivers projects is that a high dam stores a huge amount of water in reservoirs for irrigation plus electricity generation. But in a run-of-the-river project, the water is stopped at a suitable height and diverted through channels and dropped over turbines to produce electricity. The water is then channelised back to the river.

If it’s a 500 MW project, this stretch from the point where the river is diverted to the turbines can be about 15-30 kilometres long. While it’s assumed that not much harm is done to the river, in the stretch that is diverted, the local ecology and biodiversity are destroyed.

Another major impact is when they divert the river and make tunnels through mountains. These tunnels can become very big, some about nine metres through which even a truck can pass. So there are many types of exit and connecting tunnels. So what is the impact of this underground activity? What is the effect on geology and the ecology of the mountain? There’s never been any study about it, and till now, there is no such section in the Environmental Impact Assessment reports as well.

A major impact of tunnels is that they create a lot of cracks. Cracks on the houses over these tunnels, cracks on fields and in many places also trigger landslides.

Blasting disturbs the entire hydrological regime of the area, the water coming from the springs gets disturbed. Water dries up completely in many places, and in many places, suddenly, more water starts coming out. With a lot of cracks around, whenever there’s a lot of rain, it triggers landslides. But it is not believed or concluded that these landslides are triggered due to underground activity.

With tunnels everywhere between the dam and powerhouse, infrastructure such as multiple roads, the whole landscape and its forests get fragmented.

You’ll see that people are protesting against the Luhri stage II project in Himachal because it’s the pollination season, and the dust due to construction work is settling on their apple orchards. All the impacts that I’ve told you, most of them are neither studied nor are they recognised.

MA: Another aspect that often goes unnoticed is the impact of hydropower projects on smaller life forms. In 2018, Shishir Rao studied the impacts of small hydro projects on fish in the Western Ghats, a global biodiversity hotspot. Small hydro projects are dams generating less than 25 MW power.

SR: We were essentially interested in understanding how different segments of the river are impacted by the small hydropower project. So, as I explained earlier, each small hydropower project has a dam or a weir, and it impounds water and creates a reservoir. So, the water from the reservoir is diverted through a diversion canal and the diverted water is sent downstream to a powerhouse. So, the stretch of the river between the dam and the powerhouse where the turbine is situated is called the de-watered stretch.

Each small hydropower project will divide the river into three stretches, the segment upstream of the dam, which depending on whether there are more dams upstream or not, you can consider a free-flowing river if there are no dams upstream. And then you have the de-watered stretch between the dam and the powerhouse. And you have the stretch below the powerhouse, which is called the downstream stretch.

So, now all these three different segments experienced different kinds of what we say as flow regimes or different kinds of flow. We were necessarily interested in understanding how the water quality and the habitat differ in these three different segments. And how do the fish respond to the (small hydropower plant) SHP-induced flow alteration?

SR: Our study observed that the flow regime sort of drives the water quality and the habitat in all these three different segments. And we documented that in the de-watered stretch, you have completely changed water quality and habitat, where you have very low dissolved oxygen. The habitat is completely devoid of fast-flowing habitats, which you see in natural rivers and we call riffles. And these are very important habitats for some of the native fish. So, the de water stretch had reduced habitat. And the fish community in the de-watered stretch resembled the fish that you see in lakes, you know, fish that are adapted to living in isolated pools to harsh conditions.

We didn’t see many endemic or sensitive species in this de-watered stretch. Now coming to the downstream stretch where you see fluctuating water levels. Here also, the fish community was impacted, but it’s different compared to the de-watered stretch because, unlike the de-watered stretch, the downstream stretch is experiencing fluctuating flow levels right.

So, what we see here is the temperature and the dissolved oxygen sort of vary with respect to when the water is being released or held back. And the stretch that is upstream of the dam represented, more or less, an intact fish community structure. And we know this because we also studied another river that was not dammed at all, the fish communities somewhat resembled the undammed river upstream of the dam. So that was the study we conducted last year.

SR: I think the labelling of hydropower as small or large based on the ‘megawatt’, is definitely misleading.

So, what I’m trying to say here is the number might be 25 megawatts on paper. But the on-ground impacts in terms of the dam, in terms of the characteristics of the project, or the dam itself might differ from project to project. So, two projects of 25 megawatts do not have the same on-ground impacts.

MA: Why is this labelling important? Small hydro projects are exempt from Environmental Impact Assessments (EIA), a step in the environmental clearance process that’s supposed to consult local communities and assess the impacts of projects before breaking ground.

SR: Certainly, there are people who are living downstream who depend on these ecosystems. And I think their voice matters a lot. This sort of takes us into the realm of environmental justice, where we think of you know, like, ‘Who owns the water?’. Whether people who are living upstream have the right to manipulate the river in a way that downstream livelihoods are affected. And do people who live downstream have a right in saying whether a dam needs to be constructed upstream or not? So this is where hydrology and ecology meet social sciences and make it what we call a wicked conservation problem.

When I was part of the research team that was looking at small hydropower projects. We interviewed the villagers who lived nearby and we wanted to understand their perception of small hydropower projects. What we learned is that most of the villagers were sort of unaware of when these small hydropower projects were being commissioned in their backyard. And when they got to know, they were promised a sort of local electrification and employment opportunities, which did not materialise.

SR: We have a paper that talks about the perceptions of people in the Western Ghats, who live around small hydropower projects. And one of the interesting findings was that most villagers suggested that they’ve experienced increased conflict with elephants in terms of elephants raiding their crops ever since the small hydropower projects came up.

And we hypothesise that this is primarily because, during construction, small hydropower projects involve a lot of blasting because you have to create a tunnel and even after the construction, the long diversion canals are probably blocking some of the migratory routes for elephants. And this is one reason why the human-elephant conflict in the region might have increased.

MA: We talk about dams, as if like, we are planning everything keeping in mind or thinking that rainfall is going to stay or every the climate change won’t impact, water is a renewable source. So do you think that we need to factor in that erratic rainfall patterns as a factor? And do you think that we need to count the impact of climate change on rivers while focusing on dams as a source of renewable energy?

SR: I think that’s a great question. And a lot of hydrologists are slowly coming to terms with this idea, and I think it’s called stationarity. Because when you look at how civil engineers plan hydropower projects, they look at it for a 100-year term. Each dam is thought to have a life of 100 years. And they think of how reliably we can manufacture or generate hydropower from those dams. And I think the basic assumption there is that there is continuous availability of water based on some long-term rainfall data.

But as we know, because of climate change, the rainfall patterns are changing. They’re becoming more erratic, and the sustainability of hydropower projects is definitely under question if they are designed based on this assumption of stationarity. And we’ve seen that many of the hydropower projects in the Himalayas are also being affected by flash floods and these erratic rainfall patterns. So, it’s definitely a challenge for hydropower engineers to relook at how they think of the reliability of hydropower. And I think there is a need for climate change scientists and hydropower managers to sit and think of how to incorporate this uncertainty.

PB: The middle Himalayas and the lower Himalayas have been saturated with hydro projects. Now they are moving towards Upper Himalayas.

In one way, the Upper Himalayas are water storage tanks. All the major glaciers and river tributaries are in this region. If you alter the water storage tank area, you’re reducing its capacity of storage. So, I think you can call hydropower renewable to some extent. But after a point, all these hydro projects will no longer be considered ‘renewable.’ I want to add one more point – all the pressure and thrust towards the transition in green energy falls on the upper Himalayas. Even large solar power projects are eyeing cold desert areas like Lahaul, Spiti, and the upper areas of Kinnaur.

The Himalayan rivers have bumper-to-bumper projects with no distance between two dams. Whole rivers like Sutlej and Ravi are no longer flowing as they should. Now when the rivers will be destroyed, whether you consider these projects renewable or nonrenewable, I don’t see a big difference in that because we’ve destroyed the whole resource.

PB: If you look at the cost of hydroelectricity generated today, it is around Rs. 8-10 units. In the market, you can get electricity at Rs. 2.5 to 4.5 per unit. So how do we fill this cost gap? That’s being done through different policies.

For example, the new electricity bill that is being generated has a provision that makes it mandatory for each state to buy an amount of hydro energy. The state governments and the central government are also trying ways to subsidise hydroelectricity. But I think this subsidisation is mostly through the externalisation of costs which is going to the communities. In Bharmour, they have disturbed the forest area, there are cracks everywhere, and people have lost their homes and fields. If they have to pay the real cost of it all, the electricity will be very costly.

Same in Luhri, the pollination is disturbed and hence livelihoods. If we study the impact and fix a cost for it, then the electricity will be far more costly. I think our system doesn’t put out all of this and basically, the entire cost is put over a single community.

SR: Firstly, we would all agree that we certainly need dams, they are important for economic development.

MA: That’s Shishir Rao.

SR: The question is, how many do we need then? And where do we install them, Right? So, one thing that the dam managers and maybe the society at large are missing is that we tend to see we look at a river and we look at how much hydropower potential it has. And we decide whether to build a dam or not on a certain stretch of the river. But that thinking needs to change from just a river, which is a few kilometres long, to the scale of a watershed.

So, we need to look at each watershed and then think about how many dams we can have or not. And what is the total downstream impact if you put, say, ‘x’ number of dams in the watershed? So thinking of dams and rivers at a ‘watershed scale’ is one improvement that we urgently need to implement as soon as possible.

We need the managers to look at the downstream impacts too, not just to the ecology but also to the livelihoods that depend on, say, fisheries or bivalve collection. So, the participatory processes that take place during the dam construction usually involve people who are living right next to the reservoir. And this is true of large dams especially. But people who are living downstream may be living in a different state in a different administrative unit. And they might not be involved in the decision-making process. And this is because our administrative units and our political boundaries don’t necessarily match the watershed boundaries.

That is why we see so many of these water conflicts where say, Karnataka wants to divert water from the Mahadayi river, but Goa has a problem. So we need to change our thinking from, you know, these administrative political boundaries to looking at watershed boundaries.

SR: Rivers are sort of this dendritic structure, they look like nerve systems, right? So, you can plan the dams in such a way that some dams, when placed in a certain combination, can have minimal effects on the connectivity at the watershed scale. So right now, we are looking at the reverse and thinking that wherever there’s a chance to generate hydropower potential, we can install a hydropower dam there. But there are ways of optimising and looking at how the existing dams can be managed well. And by smart placement of dams, I think we can certainly do better.

MA: Thank you for listening to another episode of Everything Environment by Mongabay-India.

This show was produced and scripted by my colleague Kartik Chandramouli. Edited and mixed by Tejas Dayananda Sagar, Copy edited by Aditi Tandon.Thanks to our podcast production assistant, Ayushi Kothari, and Pooja Gupta for the GigaWhat artwork.

We’ll be out with another episode of GigaWhat soon. Take care.

Read more: GigaWhat: Renewable energy, limited land

Banner Image: Vaigai Dam, Theni district, Tamil Nadu, India. Photo by Kujaal/Wikimedia Commons.

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