Context: The Union Budget for 2024-25 promised that “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 and intermittent nature.”
Pumped Storage Projects
Overview of Pumped Storage Plants
Pumped storage hydro (PSH) plants are energy storage systems that utilize hydropower to manage electricity supply. They operate between two or more reservoirs, one at a higher elevation and another at a lower elevation. During periods of high demand, water flows from the upper reservoir to the lower one through a hydraulic turbine to generate electricity. When demand is lower, excess electricity from the grid or renewable energy sources is used to pump the water back to the upper reservoir. The overall efficiency of PSH plants typically ranges from 75% to 80%.
Types of Pumped Storage
● On-River Projects: These are similar to conventional hydroelectric projects and are directly supplied by a river.
● Off-River Projects: These involve two reservoirs at different elevations in a closed loop. Water is pumped to the higher reservoir when there is surplus power, and released to the lower reservoir to generate power when needed.
Significance of Pumped Storage
India’s ambitious goal of achieving 500GW of non-fossil fuel energy by 2030 highlights the growing reliance on renewable sources. Between 2021 and 2023, India added 23GW of non-fossil generation capacity, with 7.5GW of this coming from wind and solar energy in just eight months of 2023-24. Despite this, renewable energy is inherently variable, necessitating efficient storage solutions.
Pumped Storage Plants in India
Large Dams as Boon for PSH Plants Development
India has a significant number of large dams—5,745 in total—which offers a substantial opportunity for developing PSH plants. These plants can be established between two existing large dams or using one dam in conjunction with a second reservoir located on an elevated site.
Pumped Storage Capacity in India
The country has identified a potential capacity of approximately 120GW for PSH across around 120 sites. India currently has 3.3GW of pumped storage capacity. Key projects include those at Nagarjunasagar, Kadana, Kadamparai, Panchet, and Bhira. In comparison, China leads globally with 50GW of pumped storage supporting 1,300GW of wind and solar energy. India’s capacity needs substantial expansion to meet future renewable energy targets.
PSH in Renewable Power Generation
Challenges with Renewable Power Generation
Renewable power generation, particularly from wind and solar sources, is subject to fluctuations due to weather conditions. This variability means that grid operators need reliable backup power sources to ensure a steady supply. Hydro power can be quickly adjusted, while coal and nuclear energy require longer notice to ramp up or down.
Energy Storage Solutions
To manage the variability of renewable energy, various storage methods have been proposed, including scaling up battery storage and using compressed air. However, pumped storage remains the most widely adopted solution globally. Pumped storage projects act like large-scale natural batteries using water.
Challenges Associated with Pumped Storage Hydro (PSH) Plants
● Regulatory and Clearance Hurdles: PSH plants must secure various land, forest, and environmental clearances, which can be complex and time-consuming.
● Cost Concerns: Utilities such as distribution companies (discoms) often find PSH plants to be costly and less attractive compared to other storage options.
● High Investment and Long Gestation Periods: The significant investment required and the extended timeframes for completing PSH projects have led to low private sector participation.
● Dependency on State-Level Support: As hydro and PSH projects fall under state government jurisdiction, they need the backing of multiple policymakers and electricity regulators in addition to state governments.
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Case Study Kadamparai Pumped Storage Project Located in Coimbatore district, Tamil Nadu, the Kadamparai project, established around 37 years ago, is a prominent example of pumped storage. It consists of four 100 MW units. ● Operation of Kadamparai: The plant features a higher reservoir approximately 380 meters above a lower reservoir. During times of surplus solar power (typically around noon), the plant uses this power to pump water from the lower to the upper reservoir. Each unit requires about 20% more power to operate as a pump compared to its power generation capability. ● Transition and Efficiency: The Kadamparai plant takes about an hour and a half to switch from pumping to generating mode and about half an hour to start generating a full load. It can produce 400MW for three to four hours, supporting peak evening loads. ● Maintenance and Water Supply: The upper reservoir holds around 1 TMC feet of water. Leakage is minimal and is usually replenished by natural rainfall. |
Promoting Pumped Storage Plants in India
● Adoption of Sustainability Guidelines: India should adopt the sustainability guidelines set by the International Hydropower Association. Conducting ex-post analyses of operational storage projects can help address concerns related to energy storage and demonstrate the benefits of PSH plants.
● Transparent Allotment Process: States need to establish and announce a clear and transparent basis for allotting PSH projects. This process should differ from that used for conventional hydro projects to facilitate faster development.
● Delinking from Per-Unit Cost Basis: To expedite the development of PSH projects, they should be delinked from per-unit energy cost calculations. This will allow for more flexible and efficient project implementation.
● Cross-Border Benefits Sharing: The advantages of PSH projects can be extended across state and national boundaries. This approach can enhance collaboration and optimise the benefits of energy storage.
● Development of Market Mechanisms: India must create market mechanisms and innovative economic models to evaluate energy-storage technologies based on merit. This will ensure that PSH projects are assessed and implemented effectively.
● Prioritisation of Projects: Prioritise PSH projects based on their location, duration of storage, and the availability of pre-feasibility reports, detailed surveys, and project reports. This will streamline the planning and execution processes for successful project outcomes.
Conclusion
Pumped storage projects like Kadamparai play a crucial role in integrating variable renewable energy sources into the grid. As India aims to significantly expand its non-fossil fuel energy capacity, enhancing pumped storage infrastructure will be essential for ensuring a reliable and stable power supply.
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Probable Questions for UPSC Mains 1. Discuss the role of pumped storage hydro (PSH) plants in enhancing the stability and reliability of renewable energy integration into the power grid. Evaluate the current status of PSH plants in India and propose strategies to overcome the challenges associated with their development. (10 Marks, 150 Words) 2. Examine the significance of pumped storage projects in achieving India's target of 500GW of non-fossil fuel energy by 2030. Analyse the challenges of PSH plants in the context of India's renewable energy goals. How can the Indian government enhance the development and deployment of PSH plants to meet its renewable energy targets? (15 Marks, 250 Words) |
Source: The Hindu
