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Is Hydropower Good For Environment: Food For Thought

Hydro power plants run between 35% to 50 % of the year of their full capacity. Run of the river projects have lower power generation potential as compared to those built with huge dams.

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With rising awareness about the perils of non-renewable energy, the world is making a strong push towards clean energy. One of the of biggest components of renewable energy generated across the globe is hydropower, that is, the energy produced from turbines driven by flowing water. As per Ministry of Power, this source supplies at least 50% of electricity production in 66 countries and more than 90% in 24 countries. In India, the share of hydro power is 12.2% of total energy generation.

As per Ministry of New and Renewable Energy (MNRE) the hydropower potential of India is around 1,45,000 MW and at 60% load factor, it can meet the capacity demand of around 85, 000 MW. With only 46000 MW of Hydropower potential exploited in India, we still have a long way to go. 

Hydro power plants run between 35% to 50 % of the year of their full capacity. Run of the river projects have lower power generation potential as compared to those built with huge dams. Irrespective of the way the hydro plants are built to best exploit this source of renewable energy, there are multiple environmental repercussions associated with it. Every stakeholder needs to contemplate the impact  hydropower generation would have on the environment, and the potential impact of dams on the climate change.

As per Intergovernmental Panel on Climate Change (IPCC) (a UN body) , the major greenhouse gases are carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). These gases are emitted from natural aquatic habitats such as lakes, stagnant rivers, estuaries, wetlands and other terrestrial ecosystems like forests and soils. The hydropower dams have an ecosystem like these areas, due to which it emits Methane (CH4) and other Green House Gases.

IPCC further notes, that the global warming potential (GWP) of CH4 is 21 times higher than CO2 over a period of 100 years, revealing that CH4 is substantially more harmful than CO2 in the long run. In addition to the Methane, the dams storing water round the year also produce Carbon dioxide, and Nitrous Oxide from reservoirs, and catchment areas. However, mostly methane is generated by the decomposition of vegetation and by the microorganisms in the soil and population of fish submerged by the reservoirs, which then escapes into the atmosphere.

A research paper by renowned biologist Philip Fearnside revealed that hydropower dams located in tropical regions generate more methane than those located in temperate zones. The hot and humid climate of the area near the equator builds up an ecosystem that results in the formation and emission of the Greenhouse Gases (GHG). Another extensive study led by ecologist Bridget R. Deemer, on gas emissions from 267 large reservoirs world over, noted that more than 80 per cent of methane emissions come from water storage reservoirs created by dams, contributing almost three times more to global warming compared to carbon dioxide. 

Apart from the fact that dams are multiplying the existing climate-change challenge, it is also noteworthy that climate change in turn will also impact hydro-electricity production. Water is constantly replenished by a process of water cycle in the atmosphere and plains, but this cycle could get altered due to climate change. Other possible repercussions include floods, droughts, changes in temperature, uneven precipitation and melting glaciers. Combination of these events not only leads to infrastructure, life, and property damage due to floods, but also negatively impacts water availability, on which depends electricity generation capacity. 

Alteration of climate would lower the river discharge of major rivers like the Indus, Ganga and Brahmaputra which are fed by snow and glacier melt of the Himalayan mountains. The retreat of glaciers in the will sufficiently alter the pattern of river flow downstream, resulting in the low hydropower production. Inconsistent power generation is bound to result in writing off hydropower as a viable source of alternative energy. Scientists are also of the view that this rise in temperature will lead to irreversible changes in the environment, including odd climatic phenomenon (e.g. increased incidence of El Nino). These changes will also accelerate melting of glaciers in the Himalayan snow caps.

If we continue emitting hazardous greenhouse gases at the present rate, IPCC estimates the turn of the 21st century may see the temperature rise by 5°C. Thus, hydropower dams emitting greenhouse gases, in turn affect the water supply to dams leading to a vicious cycle. To reduce the impact of climate change, governments have agreed under the Paris Climate Change Agreement to cut the global average temperature to well below 2 degrees C above pre-industrial levels. 

Noting the hazards developing hydel power also comes with its sets of risks. Minister of State for Coal, Power, New and Renewable Energy, Piyush Goyal had rightly observed, “it is time that human beings understand that climate change is a challenge caused by humans, and ultimately it is humans who can address it.” Thus, the nation must step back not only from non-renewable sources of energy like coal and crude oil but should also be mindful while using non-renewable sources of energy such as Hydro power. 

The environmental hazards will bring with it a gamut of economic risks as well. Companies will be hesitant to invest in hydropower projects given the prevailing and potential conditions resulting from climate change. Fresh investment in Hydro is mostly limited to companies promoted by centre or state such as SJVN, THDC, NHPC, and OHPC etc. Attracting FDI (Foreign Direct Investment) in the hydroelectric field is stymied due to long gestation periods of 10-15 years, which serves as a deterrent to international investors. Also, the vast ecological impact of hydro power plants will attract protests from environmentally conscious groups. This will bring unnecessary hassles to foreign companies, serving as a further disincentive.

The Indian government is steadily moving towards renewable energy. Supporting the ambition of the government to sustain itself in the domain of hydroelectric power , Shri R.K. Singh, Minister of State, Power and New & Renewable Energy stated, 

“Generation from hydro power projects mainly depends on the availability of water.  Power generation from hydro sources has registered a compound annual growth rate of 3.3% from 0.121 BU in 2015-16 to 0.134 BU in 2018-19.” 

The government is looking to expand the domain of hydroelectricity. This is required to have good balance between hydro, coal, diesel, gas, solar and wind power generation in the country. Power is critical input for India to reach and sustainably support its ambition to become $6 trillion economy. While hydropower projects are critical for economic growth and development, it is equally important to fully assess its potential social and environmental impact in the long-term. Progress must be made sustainable to attain long term growth.


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