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Pumped Storage Projects and their Importance
Context: The Union Budget 2024-25, promised the introduction of a policy to promote pumped storage projects for electricity storage. This aims to facilitate the integration of the increasing share of renewable energy, which is variable and intermittent.
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- Energy storage methods considered included scaling up batteries and compressing air into caverns for power generation when needed.
- Today, pumped storage using water is widely adopted. This method functions like a large natural battery, storing and releasing energy through water movement.
- Hydro power can rapidly adjust output, from seconds to minutes, making it crucial for grid stability. It helped prevent blackouts during the pandemic’s lights-off campaign.
Indian Pumped Storage Policy, budget 2024:
- A policy for promoting pumped storage projects will be brought out for electricity storage and facilitating smooth integration of the growing share of renewable energy with its variable & intermittent nature in the overall energy mix.
- Renewable Energy Targets: India aims to achieve 500 GW of non-fossil power by 2030. From 2021 to 2023, India added approximately 23 GW of non-fossil generation capacity.
- 7.5 GW of the 10 GW added in 2023-24 were from wind and solar sources.
- Variable Power Generation: As renewable power generation exceeds 10% of the total, its variability (infirmity) necessitates solutions for energy storage and grid stability.
- Current State of Pumped Storage in India:
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- Existing Capacity: India currently has 3.3 GW of pumped storage capacity, with major projects including Nagarjunasagar, Kadana, Kadamparai, Panchet, and Bhira.
- Planned Expansion: 4 more projects are under construction and 2 are in advanced planning stages.
What is Pumped Storage Hydropower (PSH)?
- PSH is a type of hydroelectric energy storage that uses two reservoirs at different elevations to store and generate power. It functions similarly to a giant battery by storing excess energy and releasing it when needed.
- Early Uses: The first known PSH systems were implemented in Italy and Switzerland in the 1890s.
- Types of Pumped Storage:
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- On-River Pumped Storage: Utilises a river’s flow for power generation, similar to conventional hydroelectric projects.
- Off-River Pumped Storage: Uses two reservoirs at different elevations.
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- Water is pumped to the upper reservoir during periods of surplus power and released to generate electricity when needed. Abandoned mines can be converted into such reservoirs.
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- How It Works?:
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- Discharge Phase: Water from the upper reservoir flows down to the lower reservoir through turbines, generating electricity.
- Recharge Phase: Electricity is used to pump water from the lower reservoir back up to the upper reservoir, storing energy for future use.
- Role of Pumped Storage:
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- Energy Storage: Pumped storage systems act as large-scale batteries by using water.
- They store energy by pumping water to a higher reservoir when there is excess power and release it by letting the water flow back down to generate electricity when needed.
- Hydro Power Benefits: Hydro power can quickly adjust output (ramp up or down) to balance the grid, making it crucial for managing the variability of renewable energy sources.
Case Study: Kadamparai Pumped Storage Plant:
- Location: Tamil Nadu, near Valparai in Coimbatore district.
- Operation: The Kadamparai plant, operational for 37 years, balances the grid by utilising surplus solar and wind power to pump water to the upper reservoir.
- This stored energy is then used to generate power during periods of high demand or low renewable generation.
- Capacity: The plant has a capacity to generate 400 MW for three to four hours, adjusting its output based on solar and wind power availability.
- Efficiency: The plant requires about 20% more power to pump water than it can produce when generating electricity.