Pumped Storage Projects

Why in news?

Union Budget 2024-25 stated that a policy for promoting pumped storage projects will be brought out for electricity storage.

What are the Pumped Storage Projects?

• It is also known as pumped storage hydropower.
• Pumped storage hydropower (PSH) – A type of energy storage that uses the pumping and release of water between two reservoirs at different elevations to store water and generate electricity.
• These are like super large batteries but natural and use water and thus called as Water Battery.
• Working principle
  • When demand for electricity is low - A PSH project can use low cost energy to pump water from the lower reservoir to the upper reservoir for storage.
  • When demand for electricity is high - A PSH project can release water from the upper reservoir through a powerhouse to generate electricity.
• Traditionally, PSH plants generated power during the day and pumped at night, with modest diurnal or seasonal variation.
• Working – Take for example, Kadamparai plant near Valparai in Coimbatore district, Tamilnadu.
• The plant has a higher reservoir that is at a height of around 380 m above a lower reservoir.
• It acts as a turbine generator set producing electric power when the water flows from the upper reservoir to the lower.
• The same unit can function as a pump consuming electric power when it pumps water from lower to higher reservoir.
• Types – It is of 2 types
  • On-river type
  • Off-river type
• On-river Type – It is an open loop system connected with already existing hydroelectric project supplied by a river and thus existing hydro projects could become pumped storage.
• Off-river type  – It has two reservoirs at two different levels to which the water is pumped up or falls down to under gravity.
• They are not connected with any natural flow of rivers or streams.
• It has wider choice for sites, lower cost, shorter construction period (2-4 years) and minimal environmental impact.

What is the status of pumped storage projects in India?

• Potential - As per Central Electricity Authority, the current potential of ‘on-river pumped storage’ in India is 103 GW.
• Current capacity - India has 4.7 GW of pumped storage with 8 plants operating currently.

• Upcoming projects
  • 600 MW Upper Indravati in Odisha
  •  2,000 MW Sharavathy in Karnataka .
  • Koyna Left Bank Pumped Storage Project in Maharashtra
  • Kundah (Stage-I, II, III & IV) Project in Tamil Nadu
  • Tehri St-II Pumped Storage Project in Uttarakhand
• Projections - As per the National Electricity Plan (Generation), the installed capacity of energy storage systems including BESS is projected at 74 GW by 2031-32.

China leads the world with 44 GW of pumped storage supporting 1,300 GW of wind and solar followed by Japan and USA.

What are its benefits?

• Efficient energy generation – Energy recovery of 70–80% or more can be achieved after conversion losses and evaporation losses from the exposed water surface.
• Ensures energy security – It meets both the Base Load & Peaking Power demands efficiently and are integrated with the main grid from other energy sources.
• Durability – They have a service life of more than 40-50 years, larger than any other existing energy storage technology available.
• Cost effective – It is currently the most cost-effective means of storing large amounts of electrical energy.
• Increased life span results in a low cost of delivered energy over the life of the projects.
• Environment friendly – They don't produce harmful by-products or pose problems of disposal as in case of battery storage.
• Stabilizes renewable energy supply – Renewable sources like wind and solar energy fluctuates on basis of day, seasons & weather and so PSPs can help in balancing this fluctuation.
• Support green energy transition – It can help India achieve its Nationally Determined Contribution (NDC) targets
  • 500 GW of non-fossil power by 2030
  • 50% of installed capacity from non-fossil fuel sources by 2030
  • Achieve net zero carbon emissions by 2070
• Move towards Atmanirbhar Bharat - It primarily use indigenous technologies and domestically produced materials.
• Develops Indian economy – As it is highly capital intensive and involves local transport infrastructure for the mobilization of men and materials, local industries such as cement and steel also get impetus and drive job creation in the economy.

What are the challenges in developing PSPs?

• High capital costs – It requires huge investment to construct or alter an existing power plants into a pumped storage.
• Higher cost of pumping power - One of the prerequisites to ensure the commercial viability of a PSP unit is availability of input power at affordable tariff.
• Geographical limitation - Necessity of appropriate geography, terrain is a limiting factor the project.
• Clearances delays - Environmental clearance and forest clearance process of PSPs is very cumbersome, since these projects are treated at par with the conventional hydro projects.
• Environmental impacts – Large capacity secondary storage requires further altering the already strained mountain, valley ecosystem.

What lies ahead?

• Discarded mines including coal mines could be used as hydro storage and thereby become natural enablers for development of PSPs.
• All existing hydro projects may be examined to assess the feasibility for creating storage.
• Competitive bidding would accelerate development of grid-scale storage projects and discovery of price based on the learning.
• Supporting PSPs through concessional climate finances.
• Making them eligible for sovereign green bonds.
• Creation of a revolving fund for project preparation through project specific SPV.
• State governments and central PSUs may take up a few projects through their Undertakings.

References

1. The Hindu | Union Budget 2024 promised policy on pumped storage
2. Power Ministry | Guidelines on PSPs
3. TERI | Discussion paper on PSPs