Hydropower Generation in India: Effects of Climate Change

Indian Institute of Technology (IIT), Gandhinagar research team, led by Vimal Mishra, which included Syed Azhar Ali, Saran Aadhar and Harsh Shah from Department of Civil Engineering, has thrown important insights on the impacts of observed Climate Variability and Projected Future Climate Change on Stream-flow and Hydropower Production in India. As per their observations, for future planning, careful consideration of uncertainties in precipitation projections, along with robust and comprehensive adaptation strategies, is required, according to a new study published in journal Scientific Reports on Monday August 20, 2018 by the researchers. As Hydropower Generation in India is seeing the effects of climate change, the government must consider changes occurring due to climate change while planning new hydropower projects.

India’s top seven large hydropower projects: Nathpa Jhakri, Bhakra Nangal, Srisailam, Nagarjuna Sagar, Hirakud, Sardar Sarovar, and Indira Sagar were the subject of the study that is based on observed climate variability over the years between 1951 and 2007, and model simulations for projected climate change under different scenarios, using past observations from India Meteorological Department (IMD) and model simulations for future climate change.

Indus, Krishna, Mahanadi, and Narmada are the four major Indian sub-continental basins in which these large reservoirs are located.

• The study has found that seven large hydropower projects have experienced “significant warming” and a decline in rainfall and stream-flow during the period 1951–2007.
• Generation of hydropower from the top seven hydropower projects in India has suffered due to climate variability in the past six decades.
• Future projected climate change may also hit reservoir operations for power generation from these projects.
• All hydropower projects are projected to experience a warmer and wetter climate in the future.
• There might be a seasonal variability in reservoirs that get stream-flow from snow and glacier melt.
• Due to higher increase in air temperature, flow due to snow and glacier melt is projected to decline in the pre-monsoon season as shown for Bhakhara Nangal and Nathpa Jhakhari projects.
• Nathpa Jhakri and Bhakra Nangal where the annual mean temperature is projected to increase by more than 6.25 degrees by period 2070–2099 under the Representative Concentration Pathway (RCP) 8.5 scenario are likely to observe the highest warming.
• Other hydropower projects might see increase in annual hydropower production under the projected future climate, mainly due to increase in the monsoon season rainfall under the warming climate.
• It is also likely that the projected increase in rainfall can be due to rising extreme precipitation events in future.
• Most of the catchments of the large reservoirs are projected to experience substantial warming under projected future climate.
• There will be increase in stream-flow for the reservoirs located in central and south India primarily due to increase in the monsoon season precipitation under future climate.
• Projected increase in precipitation and stream-flow may also result in an increased sediment load to the reservoirs, which can affect the storage capacity of reservoirs and hydro power potential in future.
• Future irrigation demands can also influence the hydropower potential of the reservoirs.
• Other factors like land use and land cover changes will also be critical in future in response to urbanisation and expansion of agriculture that will affect stream-flow and so as hydropower production.