Energy Storage Systems – Significance & Challenges – Explained Pointwise

With the world shifting toward renewable energy like solar and wind, energy storage has become the missing puzzle piece for a clean energy future. India, which is rapidly expanding its renewable energy capacity, is facing a key challenge due to the vast gap between its actual operational capacity & its ambitious project pipeline.

Table of Content

What is energy storage? What are the different types of energy storage technologies? What is the status of energy storage capacity globally & domestically? What is the need for energy storage? What are the challenges associated with energy storage? What are various government initiatives to promote battery storage? What should be the way forward?

What is energy storage?

• Energy storage refers to systems that can store excess renewable electricity during periods of high generation & discharge it when demand rises but power generation remains low.
• At its core, energy storage systems convert electricity from renewable sources such as solar & wind, when it is available, into forms that can be stored.
• Energy storage systems are required because of the core problem associated with the renewable energy: Supply-Demand Mismatch. Renewable energy sources like solar and wind are intermittent — they generate power only when the sun shines or the wind blows, not necessarily when people need electricity. Demand, on the other hand, follows human patterns (mornings, evenings, seasonal peaks) that rarely align with natural generation patterns.
• Energy storage is one of the most critical challenges in the transition to clean energy.

What are the different types of energy storage technologies?

Pumped Hydro Storage (PHS)	Two reservoirs at different elevations. When energy is cheap/excess, water is pumped to the upper reservoir. When energy is needed, water is released back down through turbines to generate electricity.
Battery Energy Storage (BESS)	Stores electricity chemically & discharges it through chemical reactions when needed. Lithium-ion batteries, particularly lithium iron phosphate (LHP) batteries, are the dominant technology because of their falling costs, high efficiency & long operational life. This is currently the fastest-growing sector of energy storage.
Concentrating Solar-Thermal Storage Systems	This technology uses mirrors that capture & focus sunlight onto a receiver. As the receiver gets heated, materials such as molten salt are circulated inside the receiver to store the heat. The stored heat can later be used to produce steam. This steam is converted into mechanical energy in turbine, which powers a generator to produce electricity.
Compressed-Air Energy Storage Systems	Excess electricity powers a compressor to pump air into a sealed underground cavern (salt dome, aquifer, or depleted gas field). To retrieve energy, the compressed air is released, heated (natural gas is often used to reheat it), and expanded through a turbine.
Flywheel Energy Storage Systems	A large, heavy rotor (flywheel) is spun at very high speeds (up to 50,000+ RPM) in a near-frictionless vacuum. Energy is stored as rotational kinetic energy. To extract power, the flywheel’s momentum drives a generator, slowing it down. Flywheels can discharge almost instantly, making them perfect for stabilizing short-term grid fluctuations.
Gravity Energy Storage Systems	GESS use electricity to lift heavy weights to higher elevations. When electricity is needed, the weights are lowered, converting gravitational energy back into electrical through generators.

What is the status of energy storage capacity globally & domestically?

• China continues to dominate, accounting for ~60% of new installations in 2025, followed by the United States at 16% .
• Globally, PHS & BESS are two most widely deployed electricity storage technologies. While batteries are growing fast, pumped storage hydropower (PSH) remains the largest source of grid-scale energy storage worldwide, with approximately 160 GW of operating capacity and a massive pipeline of prospective projects.
• India has approximately 7 GW of operational Pumped Storage (PSP) capacity & under 1GW of BESS operational capacity. The total planned capacity of 174 GW is expected to support a national grid with 509 GW of solar and 155 GW of wind by 2036, this includes 80 GW of BESS & 94 GW of PHS.
  

  

What is the need for energy storage?

1. Smoothing Out Variability: Solar panels produce peak power at midday; wind turbines may generate most at night or in storms. Without storage, this surplus is wasted. Storage captures excess generation and dispatches it when needed.
2. Grid Stability & Frequency Regulation: Power grids require near-perfect real-time balance between supply and demand. Traditional fossil fuel plants can ramp up or down on demand. Renewables cannot. Storage acts as a buffer, absorbing or injecting power within milliseconds to keep frequency stable.
3. Replacing “Peaker” Plants: To handle sudden spikes in energy demand (like hot summer afternoons), utilities rely on peaker plants. These are typically natural gas plants that sit idle most of the year but can be turned on quickly. Because they only run occasionally, they are very expensive to operate and are often the dirtiest, most polluting plants on the grid. Battery storage can serve the same role more cheaply and cleanly.
4. Enabling Higher Renewable Penetration: Without storage, grids become unstable above ~30–40% renewable share. Storage is what makes 70–100% renewable grids physically possible — it’s the bridge between generation and consumption.
5. Reducing Curtailment (Wasted Energy): When wind turbines or solar farms produce more electricity than the grid can safely handle, grid operators are forced to intentionally shut them off or disconnect them. This is called curtailment — wasting clean energy. Storage eliminates this waste.
6. Energy Independence & Resilience: Stored energy provides backup during outages, reduces reliance on fuel imports, and makes microgrids and remote communities self-sufficient.
7. Transmission Congestion Relief: Storage located near load centers can reduce the need for expensive long-distance transmission upgrades by serving local demand directly.

What are the challenges associated with energy storage?

1. Massive Gap Between Capacity & Deployment: India’s storage ambitions on paper vastly outpace what’s actually been built. India’s limited domestic cell manufacturing base means that only 219 MWh of BESS capacity is operational from 12.8 GWh auctioned between 2022 and May 2025, largely reflecting execution gaps driven by high financing costs and aggressive underbidding.
2. High Upfront Capital Costs (CapEx): Building a grid-scale battery farm or a pumped hydro station costs billions of dollars. Unlike a gas turbine, which can be built in phases, a pumped hydro plant requires the entire dam, reservoir, and turbines to be built before it generates some revenue.
3. Round-Trip Efficiency Losses: No energy storage system is perfect; energy is always lost when converting it from one form to another and back again. This is known as round-trip efficiency. Batteries are highly efficient, retaining about 80% to 90% of the energy put into them. Hydrogen Storage is the least efficient. Generating hydrogen via electrolysis, compressing it, storing it, and later converting it back to electricity via a fuel cell or turbine results in a round-trip efficiency of only 30% to 45%. This means more than half of the clean energy captured is lost as waste heat.
4. Geopolitical Monopolies: The mining and processing of essential battery materials—such as lithium, cobalt, nickel, and manganese—are concentrated in just a few countries. For instance, a vast majority of the world’s cobalt is mined in the Democratic Republic of Congo, and China dominates the global refining capacity for almost all of these minerals.
5. Degradation and Limited Lifespan: Unlike a coal plant or a hydroelectric dam that can operate for 40 to 100 years with regular maintenance, chemical batteries wear out. Most grid-scale batteries only last about 10 to 15 years before their capacity drops significantly and they need to be replaced. This limited lifespan introduces a recurring long-term cost for grid operators who must constantly plan for battery replacement.
6. Recycling Hurdles: Spent lithium-ion batteries are very difficult and expensive to recycle due to their complex chemical mixtures. As millions of electric vehicles and grid batteries reach the end of their lives over the next decade, managing this wave of electronic waste is a massive looming challenge.

What are various government initiatives to promote battery storage?

1. Advanced Chemistry Cell (ACC) PLI Scheme: Overseen by the Ministry of Heavy Industries, this ₹18,100 crore Production-Linked Incentive scheme aims to establish 50 GWh of competitive domestic battery manufacturing.
2. Viability Gap Funding (VGF) Scheme: Provides financial support to make BESS projects commercially viable and accelerate early deployment. The government is aggressively deploying VGF to lower project costs for developers.
   
3. Energy Storage Obligations (ESO): Similar to Renewable Purchase Obligations, the government has legally mandated that power distribution companies (DISCOMs) must source a specific percentage of their electricity from storage-backed systems, scaling up to 4% of total energy consumption by 2030.
4. Transition from Plain Renewable Tenders: Renewable Energy Implementing Agencies (like SECI, NTPC, and NHPC) have been directed to stop offering standard solar or wind contracts. Instead, they are pushing “Round-the-Clock” (RTC) and “Firm and Dispatchable Renewable Energy” (FDRE) tenders, forcing developers to integrate batteries to guarantee stable power delivery. 
5. Waiver of Inter-State Transmission System (ISTS) Charges: To lower operational expenses, the government has waived inter-state transmission fees for electricity utilized by energy storage systems, making it cheaper to transport stored green energy across state lines.
6. India Battery Storage Vision 2047: Looking long-term, ministries are already formalizing a policy framework to introduce financial backing and interest subventions specifically for Long-Duration Energy Storage (LDES) technologies to manage seasonal energy shifts.

What should be the way forward?

1. Scale Domestic Manufacturing:
   Relying entirely on imported battery cells (predominantly from China) poses a massive geopolitical and economic risk. India must build its own manufacturing ecosystem. The government’s Advanced Chemistry Cell Production-Linked Incentive (PLI) scheme is a great start.
   However, since India has limited domestic lithium reserves, the country must heavily fund research and commercialization of alternative chemistries like Sodium-ion and Zinc-air batteries, which are well-suited for stationary grid storage.
2. Leverage Massive Pumped Hydro Projects (PHS): While chemical batteries dominate short-duration needs (2–4 hours), India has immense natural topography suited for Pumped Hydroelectric Storage, which is ideal for long-duration storage. Unlike lithium-ion batteries, PHS projects have a lifespan of over 50 years and do not rely on scarce critical minerals.
3. Decentralize Storage: Large battery farms aren’t the only solution; storage needs to be deployed at the consumer level. Farmers using solar water pumps and residential homes with rooftop solar should be incentivized to add small battery packs. This turns consumers into “prosumers” who can support the grid locally.
4. Accelerate Grid Infrastructure: Storage without grid readiness is futile. Investments under the Green Energy Corridor programme are expanding transmission infrastructure to connect renewable-rich regions with demand centres, reducing curtailment risks and improving system integration.
5. Replacing Diesel Generators: India has mandated a phased shift away from highly polluting diesel generator sets for backup power in commercial buildings. Incentivizing these buildings to switch to Battery Energy Storage Systems (BESS) will drastically cut urban air pollution.
6. Build a Battery Recycling Ecosystem: India must get ahead of the end-of-life problem before it becomes a crisis. A circular economy framework — including second-life battery applications (e.g., retired EV batteries repurposed for grid storage) and formal recycling infrastructure — will reduce material costs, environmental harm, and long-term import dependence.

UPSC GS-3: Energy Infrastructure Read More: Indian Express