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Energy Storage in India- Battery Storage Technology
By Abhishek Sreekant



Today, India’s 372 GW of installed electricity generating capacity is significantly higher than its nearly 182 GW of peak demand. In fact, India’s coal generation capacity alone is higher than the country’s peak demand. Yet, the irony lies in the fact that shortages and blackouts are endemic. The reality is that many of India’s shortages and blackouts are the result of insufficient fuel availability and high costs. Conventional coal-fired power plants constituted a major share of the new capacity built between 2005 and 2014. Despite estimates that India has huge reserves of coal, the country’s ability to mine that coal and move it around the country is constrained. Further, unlike domestic coal, the price of imported coal is unregulated; its price is set in the international market which can be quite volatile. Imported coal in the recent past has been significantly more expensive than Indian coal.


For decades, as demand for power has grown, India has added large-scale conventional power resources. Now, however, with solar and wind power becoming commercially available, it will become convenient and usable for the future market. One of India’s major advantages today and going forward is that it’s RE potential is vast and largely untapped. Recent estimates show that India’s solar potential is greater than 750 GW and its wind potential could be higher than 700 GW.


In India today,


  • Solar photovoltaic cells are cheaper than natural gas-based production.


  • New wind projects at the point of generation are cheaper than the comparable costs of power from new imported coal-based projects.


The conventional fossil fuel-based power plants take years to become operational. But RE generation can be built quickly – thus matching supply and demand quickly, and simultaneously reducing the risks to buyers and sellers. Moreover, the cost of integrating and managing the RE is comparatively moderate.


The above benefits come with certain challenges. RE is relatively more capital-intensive than conventional power plants. The output of wind and solar photovoltaic generation is variable and uncertain. Thus, to capture the benefits, India would need to make available the necessary capital, and get comfortable with managing the variability and uncertainty of RE generation in conjunction with the existing and planned fossil fuel-based plants and large power plants.

Bringing RE into the Picture


I think we should not fall into the notion that traditional energy is the main player in India's electricity production. We should consider Renewable Energy sources to be the main occupants and build our energy systems around it. This is because, renewable energy is the future. The key difference between conventional generation (e.g. coal, natural gas, nuclear, hydro) and a system based on renewable energy (e.g., wind, solar) is the need for raw fuel that in turn necessitates a complex, reliable, and expensive upstream infrastructure for its production and transportation to the generator site. In order for it to function, the physical, economic, and institutional aspects of not only the power grid, but also the entire upstream infrastructure must work in sync.


Rapid Growth and Demand


The peak energy demand across India amounted to approximately 182 thousand megawatts for the fiscal year 2020. Not only is the demand for electricity growing, but also the load profile is also changing as greater income leads to increased purchases of appliances – especially for space cooling – that has a significantly different load profile from historically common loads such as lighting. Thus, Renewable Energy is the way forward. However, with the production of energy, there is a need to focus on storage of energy, particularly on electricity and storage of electricity.


Electricity in India and Forms of Energy Storage Systems


Electricity generated from any source, whether traditional or renewable, needs to be consumed instantly. This limitation of electricity has led to the development of energy storage technologies. Energy storage has been part of the electric system for decades. Energy storage technologies provide flexibility in the use of electricity, for both centralised and decentralised supply provisions. Conventional use of storage systems by batteries (in electronic goods, vehicles) and accumulators (inverters and UPS as electricity backup solutions) have been driven by commercial and technological considerations (and requirements), with little policy directive to incentivise the use of these novel solutions.


In India, lead-acid batteries have been the primary storage solution for a range of stationary and portable applications. Increasingly, with the potential application of energy storage in unexplored areas such as large grid-connected systems for applications including peak shaving, ancillary services, grid stability etc. and novel applications in electrical vehicles, a lot of the research and development (and the resulting products) will find use in replacing conventional technologies in other existing applications. The demand from telecom, micro-grids, rooftop solar and diesel generator replacement markets are also going to intensify the demand for advanced battery technologies and storage solutions.


The Indian Energy Storage Alliance (IESA), in 2013, estimated that by 2020, the market potential in India for energy storage systems in renewable energy applications alone would be in the vicinity of 6000 MW. The potential for energy storage has been revised to about 15 – 20 GW by 2020 after the ambitious renewable energy targets of 175GW of renewable energy capacity by 2022. Furthermore, India’s international commitment made to the United Nations Framework Convention on Climate Change(UNFCCC) in October 2015, projects 40% of the electricity capacity in 2030 to be non-fossil. The role of energy storage, in an energy mix that includes significant contributions from solar and wind power, cannot be emphasised enough.

The dynamics of the battery market in India are changing rapidly, with the increasing demand for advanced battery technologies and emerging application areas. It is thus important to study the emerging landscape of energy storage technologies and their applications in the renewable energy segment. On the technical side, storage techniques can be primarily classified into the following categories:


  • Electrical- Electrical Energy storage system includes technologies like supercapacitors and Superconducting Magnetic Energy Storage.


  • Mechanical- Mechanical energy storage systems house a wide range of systems such as pumped hydro storage (PHS), flywheel and compressed air energy storage (CAES) system.


  • Thermal - Thermal storage systems use materials which are capable of storing energy for months, hence prove to be useful for inter seasonal storage. Molten salt like potassium nitrate, calcium nitrate etc, have the property to absorb and store heat, which can be released later to heat the water when required.


  • Chemical- Chemical energy storage includes technologies like Synthetic Natural gas (SNG),H2 and fuel cells. Fuel cell technology has been in use for about 50 years now. When hydrogen stored under high pressure in a tank is combined with oxygen obtained from the atmosphere, the reaction produces water and electricity. As an energy storage media, during periods of excess power generation, electricity can be diverted for electrolysis (endothermic process) to generate hydrogen and oxygen. During power demand, the gases can be combined to generate electricity and water.


  • Electrochemical- Electrochemical Storage is the most commonly known form of energy storage these days. Lead acid, Li-ion, and more recently redox flow batteries are the prominent battery technologies available in the market. Most of the installations across the world currently use lead acid battery technology. Tesla’s Powerwall, essentially a rechargeable Li-ion battery offers seamless integration into the house’s electricity network and gives load shifting capability to the consumer. As the big market players like LG Chem, Panasonic and others enter into mass production of battery technologies, the prices of batteries will reduce further owing to the scale of economy.


Energy Storage System (ESS) is fast emerging as an essential part of the evolving clean energy systems of the 21st century. Energy storage represents a huge economic opportunity for India. Ambitious goals, concerted strategies, and a collaborative approach could help India meet its emission reduction targets while avoiding import dependency for battery packs and cells. This could help establish India as a hub for cutting-edge research and innovation, boost its manufacturing capabilities, create new jobs, and foster economic growth.


I believe that one of the major forms of energy is electrical energy, which either has to be used immediately or stored carefully. Hence, I believe that one of the most important forms of Energy storage technology is “Battery Storage technology.”


India’s strengths in IT and manufacturing, it’s entrepreneurial and dynamic private sector, and it’s visionary public and private sector leadership are the key factors in realizing these ambitions. Creation of a conducive battery manufacturing ecosystem on a fast track could cement India’s opportunity for radical economic and industrial transformation in a critical and fast-growing global market. India is committed to reducing emission intensity up to 33-35% from the 2005 level by 2030 and set the target to 40% non-fossil fuel-based electricity generation in the energy mix. This requires radical measures to scale up the share of renewable energy (RE) besides the ongoing program of 175 GW RE by 2022. The new targets for RE by 2030 could be in the order of 350 to 500 GW. Integration of such massive amounts of RE which are intermittent and distributed in the power system pose serious challenges to grid operations.


With an installed capacity of 73.74 GW of variable renewable energy (VRE) of solar and wind, India ranks fourth in the world in terms of installed capacity, behind China, USA and Germany. Of the total installed capacity of 372.69 GW, VRE accounts for 19.79%.


With no facility to store electricity as of now, the electricity produced in the power plants and fed into the grid (an interconnected network for delivering electricity) should ideally be the same as the electricity consumed. If the electricity demand is more than the supply, the frequency at which the grid equilibrium is maintained (50 Hertz) will come down and vice versa. An imbalance in frequency when it goes beyond permissible limits leads to grid collapse and blackout (power outage).


Since solar radiation and wind speed keep varying, the frequency cannot be maintained at 50 Hz. Electricity demand also keeps varying. Hence, grid operators cannot match supply and demand, if only power from VRE sources is fed into the grid. Since these technical limitations hamper more absorption of renewable energy, a mix of thermal and hydro power are used for maintaining the balance, as power output from these plants can be controlled.


What are batteries?


A battery is a device consisting of one or more electrochemical cells with external connections for powering electrical devices.


What is a battery energy storage system?


A Battery Energy Storage System (BESS) is a technology developed for storing electric charge by using specially developed batteries. The underlying idea being that such stored energy can be utilized at a later time. Enormous amounts of research have led to battery advances that has shaped the concept of Battery Energy Storage System into a commercial reality.


Battery Energy Storage Systems (BESSs) are a subset of Energy Storage Systems (ESSs). Energy Storage System is a general term for the ability of a system to store energy using thermal, electro-mechanical or electro-chemical solutions. A BESS typically utilizes an electro-chemical solution.

Essentially, all Energy Storage Systems capture energy and store it for use at a later time or date. Examples of these systems include pumped hydro, compressed air storage, mechanical flywheels, and now BESSs. These systems complement intermittent sources of energy such as wind, tidal and solar power in an attempt to balance energy production and consumption.


Energy storage results in a reduction in peak electrical system demand and ESS owners are often compensated through regional grid market programs. Regulators also offer incentives (and in some cases mandates) to encourage participation.


Why BESS over other storage technologies?


BESS has an advantage over other Storage technologies as it has a small footprint and no restrictions on geographical locations that it could be located in. Other Storage technologies like Pumped hydro storage (PHS) and Compressed air energy storage (CAES) are only suitable for a limited number of locations, considering water, siting-related restrictions and transmission constraints. Energy and power densities of some technologies are as follows:


Accordingly, BESS utilizing Lithium Ion technology offers high energy and power densities that are suitable for utilization at distribution transformer level. The available space at the distribution transformer setup can be used to locate the BESS,


The night peak that needs to be managed is about 4 hours maximum and hence the discharging time required for a particular BESS is less than 4 hours. Further, the rated apparent power of distribution transformers is in the range of 160 kVA, 400kVA up to 1 MVA (for rural, urban and metropolitan areas respectively).


Therefore, BESS only needs to supply a part of that capacity during a maximum of 4 hours of peak time.


The following figure illustrates the positions that different technologies have in space, considering power, energy and discharge time as dimensions.

Power, Energy and Discharge Time of Energy Storage Technologies


Characteristics of a Battery Energy Storage System


  • Round-trip Efficiency — Indicates the amount of usable energy that can be discharged from a storage system relative to the amount of energy that was supplied. This accounts for the energy lost during each charge and discharge cycle. Typical values range from 60% to 95%.


  • Response Time — Amount of time required for a storage system to go from standby mode to full output. This performance criterion is an important indicator of the flexibility of storage as a grid resource relative to alternatives. Most storage systems have a rapid response time, typically less than a minute. Pumped hydroelectric storage and compressed air energy storage tend to be relatively slow as compared to batteries.


  • Ramp Rate — Ramp rate indicates the rate at which storage power can be varied. A ramp rate for batteries can be faster than 100% variation in one to a few seconds. The ramp rate for pumped hydroelectric storage and for compressed air energy storage is similar to the ramp rate for conventional generation facilities.

  • Energy Retention or Standby Losses — Energy retention time is the amount of time that a storage system retains its charge. The concept of energy retention is important because of the tendency for some types of storage to self-discharge or to dissipate energy while the storage is not in use.

  • Energy Density — The amount of energy that can be stored for a given amount of area, volume, or mass. This criterion is important in applications where area is a limiting factor, for example, in an urban substation where space could be a limiting constraint to site energy storage.


  • Power Density — Power density indicates the amount of power that can be delivered for a given amount of area, volume, or mass. In addition, like energy density, power density varies significantly among storage types. Again, power density is important if area and/or space are limited or if weight is an issue.


  • Safety — Safety is related to both electricity and to the specific materials and processes involved in storage systems. The chemicals and reactions used in batteries can pose safety or fire concerns.


  • Life span — Measured in cycles.


  • Depth of Discharge (DoD) — Refers to the amount of the battery’s capacity that has been utilized. It is expressed as a percentage of the battery’s full energy capacity. The deeper a battery’s discharge, the shorter the expected lifetime. Deep cycle is often defined as 80% or more DoD.


  • Ambient temperature — Has an important effect on battery performance. High ambient temperatures cause internal reactions to occur, and many batteries lose capacity more rapidly in hotter climates.



Important Considerations for Battery Selection

Various parameters to decide the type of battery to be deployed


Many criteria play an important part in selection of the battery for BESS as depicted above. These range from regulatory issues to cost and technology dimensions. However, the biggest deterministic factor for battery selection is the application that the BESS is required to service, along with performance requirement management.


Aspects of Battery Energy Storage Systems’ Economics

Parameters for determining the BESS economics


The optimization of BESS Economics lies in closely triangulating the market parameters

, consumer parameters and storage system parameters. Each of these lumped parameters have multiple sub parameters which play a significant role in the overall economics of the system.


Classification of BESS by Battery Types


BESSs intrinsically uses electro-chemical solutions which manifest in some of the following Battery Types:


  1. Lithium-ion — These offer good energy storage for their size and can be charged/ discharged many times in their lifetime. They are used in a wide variety of consumer electronics such as smartphones, tablets, laptops, electronic cigarettes and digital cameras. They are also used in electric cars and some aircraft.

  2. Lead-acid — These are traditional rechargeable batteries and are inexpensive compared to newer types of batteries. Uses include protection and control systems, back-up power supplies, and grid energy storage.

  3. Sodium Sulfur — Uses include storing energy from renewable sources such as solar or wind

  4. Zinc bromine — Uses include storing energy from renewable sources such as solar or wind.

  5. Flow — Flow batteries are quite large and are generally used to store energy from renewable sources.


Why is BESS gaining popularity?


Decreasing costs: A major factor in the rapid increase in the use of BESS technology has been a 50% decrease in costs of energy storage over the last two years. While costs are still high compared to grid electricity, the cost of energy storage has actually been plummeting for the last 20 years. Storage systems at the utility customer level can also result in significant savings to businesses through smart grid and Distributed Energy Resource (DER) initiatives, (where cars, homes and businesses are potential stores) suppliers and users of electricity.


Security of supply: Storage technologies are also popular because they improve energy security by optimizing energy supply and demand, reducing the need to import electricity via inter-connectors, and also reducing the need to continuously adjust generation unit output.


In addition, BESS can provide system security by supplying energy during electricity outages and minimizing the disruption and costs associated with power cuts.


Financial incentives: Many governments and utility regulators are actively encouraging the development of battery storage systems with financial incentives, which is likely to lead to further growth.


Risks involved in using BESS: While the use of batteries is nothing new, what is new is the size, complexity, energy density of the systems and the Li-ion battery chemistry involved — which can lead to significant fire risks.

Thermal runaway: ‘Thermal runaway’ — a cycle in which excessive heat keeps creating more heat — is the major risk for Li-ion battery technology. It can be caused by a battery having internal cell defects, mechanical failures/damage or over voltage. These lead to high temperatures, gas build-up and potential explosive rupture of the battery cell, resulting in fire and/or explosion. Without disconnection, thermal runaway can also spread from one cell to the next, causing further damage.


Difficulty of fighting battery fires: Battery fires are often very intense and difficult to control. They can take days or even weeks to extinguish properly and may seem fully extinguished when they are not.


Failure of control systems: Another issue can be failure of protection and control systems. For example, a Battery Management System (BMS) failure can lead to overcharging and an inability to monitor the operating environment, such as temperature or cell voltage.

Battery Storage Technology in India: Storage battery for grid stability

India has a target of 175 GW of renewables by 2022. As the country transitions more towards renewable energy sources, it is becoming imperative to ensure grid stability. One of the solutions for a balanced grid is energy storage batteries. When the energy generation is more than the demand, it can be stored in the batteries and used when generation comes down and/or demand increases.


Batteries have been in use for long, but not on a scale that could support the grid. The world’s first and largest grid-scale battery called Hornsdale Power Reserve (HPR) came up in South


Australia in 2017, after the state had a blackout in September 2016. The 100 MW capacity power reserve runs on lithium-ion batteries.


Lithium ion, lead acid, redox flow and molten salt (sodium sulphur) are the battery storage technologies that are available today. However, the 2019 Nobel winning Lithium ion (Li-ion) technology dominates the market. Li-ion would be ideal for hourly or daily applications like peak shaving (managing demand to eliminate demand spikes) and grid stability as they have high efficiency and power handling capacity, besides decreasing prices. Further, maintenance required in lithium batteries is very less and they have small footprint due to their high energy density.


India’s first grid-scale battery is at a substation located at Rohini, New Delhi, operated by Tata Power-Delhi Distribution Limited (DDL) since March 2019. “Tata Power collaborated with AES Corporation and Mitsubishi Corporation to set up Asia’s largest grid-scale battery energy storage system (BESS) at Rohini. At the 10MWh plant, Li-ion batteries are used, with the support of Advancion technology, to operate the plant seamlessly,” said the Tata Power-DDL spokesperson. It has been extensively used for peak load management, deviation settlement mechanism management, etc. and provides enhanced power supply, by addressing various technical issues. The battery occupies 625 sq.m, covering the BESS, isolation transformer and firefighting installation. The spokesperson says that there is scope for reduction in space with container-based solutions.


Cost factor


As per a December 2019 BloombergNEF report, battery price which was more than $1,100 per kilowatt-hour (kWh) in 2010, came down to $156/kWh in 2019. The price is expected to reach $100/kWh by 2025; and with the new battery manufacturing facility being proposed in India, we feel BESS would scale up in the near future, to manage the power grid as well as the electric vehicle infrastructure.


Once the prices come down, renewable energy generators may come into the picture too. The installed unit cost of a grid-scale battery with two hours of storage (e.g. 100 MW power rating, 200 MWh energy storage capacity) is approximately $340 / kWh. Further improvements in battery technology and more efficient integration into complete energy storage systems are expected to further reduce costs. A large increase in global battery manufacturing associated with deployment of electric vehicles is also expected to reduce battery costs for grid-scale battery storage. Meanwhile, reports indicate that Tesla, the HPR battery manufacturer, has recovered costs and that it reduced electricity costs by $116 million.




Each nation’s energy storage potential is usually reliant on the combination of energy resources present, physical infrastructure available including grid position, regulatory framework, energy supply, demand trend, and population demographics of such nations. The energy storage market worldwide is presently constrained by various barriers, which include lack of understanding of storage technology, regulatory framework, significant upfront investments, value recognition, absence of subsidised financing and availability of skilled and experienced workforce to manage energy storage systems.


Despite these prevalent challenges, energy storage as an innovative solution is increasingly being sought globally to meet the emerging requirements of the developed as well as the developing nations. Installation of battery storage energy systems (BESS) is increasing dramatically as energy markets are being transformed to allow the use of more diversified resources. Reports that are generally available forecast that the global BESS market is expected to exceed more than $9 billion by 2024 at a compound annual growth rate of 34 per cent. BESS is crucial for enabling the effective integration of renewable energy and unlocking the advantages of local generation and a clean, robust energy supply, with value being demonstrated to grid operators for management of the variable generation of renewable energy.


With India aiming to set up 175 gigawatt (GW) of renewable energy capacity by 2022, deploying BESS will only aid network operators, mitigate renewable resources’ variability, and reduce congestion on the grid. The growing renewable power capacity clubbed with the appealing business for electric vehicles will strengthen the rationale behind BESS.


Cheap batteries mean that wind and solar will increasingly be able to run “when the wind isn’t blowing and the sun isn’t shining”. The success of energy storage systems will, however, have to be backed by the government and they will also have to consider providing policy incentives in line with practices in countries such as South Korea. Deployment of BESS may not be the ultimate resolution to the rising electricity demand in India with installed capacity likely to cross 600 GW by 2030, but also it’s potential cannot be undermined, especially when BESS can play a pivotal role in addressing the call for better demand response in India.










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