Hydropower Technology — What Does Our Future Hold?
The road to a clean energy future is paved with innumerable challenges due to our past choices. How do we make the best of it?
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Many countries across the world are struggling with power shortages. Socio-economic development has increased the need for power at an increasingly rapid pace. Hydropower plays a crucial role in meeting the world’s power requirements. Globally, the annual net hydropower additions were expected to exceed 18 gigawatts (GW) in 2020 and continue their steady growth in 2021 and 2022. The installed global hydropower capacity in 2019 was 1307 GW. In 2020, it reached 1330 GW. This shows a 1.6 percent growth in hydro energy as compared to 2019.
World Hydroelectric Capacity by Country Basis:
During 2020, hydropower projects totalling 21 GW in capacity were put into operation, upon 2019’s 15.6 GW. Nearly two-thirds of this growth came from China, which saw 13.8 GW of new capacity. Pumped storage hydropower totalled 1.5 GW of the new additions in capacity, upon the 304 MW added in 2019. Most of this was in China (1.2 GW), with Israel also commissioning the 300 MW Mount Gilboa project under an innovative financing model.
Hydropower continues to be the largest renewable energy source — the others include offshore, onshore, wind, solar, etc.
The impact of large dams on the environment is enormous — Renewable energy needs to take over.
But what remains unacknowledged is that the dams built to generate hydropower leave a significant ecological footprint. Environmental groups claim that these projects damage river ecology, impact the water supplies downstream, cause earthquakes, floods, droughts and landslides, affect the indigenous populations, cause habitat fragmentation and displace wildlife. Studies suggest that hydropower plants emit as much greenhouse gases as fossil fuel plants.
With so much emphasis being given to the climate crisis and the need to opt for clean energy sources — hydroelectric energy deserves to be discussed in depth.
Knowing everything we do about the impact of hydropower potential by country on the environment, most experts agree that new dams must not be built to harness hydropower. After a century of rapid changes, there has been a slowdown in the growth of hydroelectric projects in many parts of the world. And yet, many such projects are being greenlit in the world even now. Take the example of China, whose growth over the last 10 years has not seen a significant reduction i.e. 3 percent (see table). It has commissioned two flagship projects in the Yarlung Tsangpo river. Even India has announced the 3,097-megawatt Etalin Hydroelectric Project in Dibang Valley in Arunachal Pradesh. The Asian nation has seen a growth rate of 1.4 percent in the last five years.
World Hydropower Statistics:
Developed nations like the US and Canada are moving away from hydel power with a growth rate of 0 percent and 0.6 percent respectively. Developed countries are phasing out hydropower in part due to environmental and social impacts, but also due to the increased financial cost of building and maintaining dams. The world could take inspiration from the US, which has successfully removed 91 dams in 2017 and 99 dams in 2018. Moreover, there are no new construction projects in the pipeline for the country. The environmentalists have successfully protected river and freshwater ecosystems and prevented other significant threats posed by large and small dams.
The Story of Aging Dams
The conversation about newer and bigger dam projects is incomplete without taking a closer look into the past. For instance, India has an aging water infrastructure posing a grave threat to its surrounding regions. According to a United Nations report, Ageing water infrastructure: An emerging global risk, over 1,000 large dams in India will be roughly 50 years old in 2025. Some dams that have often been called the “temples of India” are already half a century old. To avoid future man-made disasters, the World Bank announced a $250-million loan to India for an ongoing project to “strengthen dam safety” in December 2020.
Perhaps, the older dams can be incentivized to further their usage. An aging dam has reduced capacity because soil replaces water in the reservoirs. Hence, the storage capacity of a dam is depleted over time and slowly becomes obsolete. Add to that, the soil build-up in small dams takes place much faster. Then there are other issues of dam failures, floods, and more that could be hazardous for humans and the ecology.
Recognizing the challenges related to hydropower, the International Hydropower Association (IHA), formed under UNESCO in 1995, began work on the IHA Sustainability Guidelines in 2004. This has resulted in the Hydropower Sustainability Assessment Protocol (HSAP), a “multi-stakeholder tool for assessing projects at all phases of their lifecycle.”
What’s the Solution? A Path Towards Green Energy
But the larger question that arises from this debate is — how do we meet the Sustainable Development Goals (SDGs) by harnessing hydropower by sustainable means?
Is it time for us to turn to alternative technologies as renewable energy sources? As per the International Energy Agency, we need to harness 800 GW of additional hydropower to meet our Sustainable Development Goals.
We know that using water to generate electricity has been in practice since the 1800s — with the first hydroelectric project set up in 1878. And as the world takes strides in developing newer technologies, numerous innovations to harness hydropower sustainably have also been made.
Scientists have also been finding ways to harness large hydropower with methods that do not cause harm to fish populations. While not everything can be controlled, scientists have worked on minimizing certain risks.
These include technologies like fish-friendly turbines as well as the development of water-lubricated bearings in turbines.
An eco-hydraulics approach is adopted in small hydropower plants’ design to minimize the mortality of fish populations. For large dams, fish passage facilities and fish-friendly turbines can be integrated to enable upstream and downstream migration of fish in the event of a dam impeding their migration.
The three-blade Alden turbine works with a 93.6% efficiency and prevents the mortality of fish by 98% or greater. Another technique involves the Minimum Gap Runner turbines used for high head turbines.
If such solutions are made a part of large dams’ designs, it could mitigate the risks to river ecology.
It’s important for public and private stakeholders to focus on such alternative energy to mitigate the greenhouse effect of harnessing hydropower through large dam projects.
More importantly, we have to weigh the pros and cons of building concrete in the middle of river systems and its impact on the natural ecosystems. Only then can we utilize a hydropower plant to sustainably meet our energy goals.