Battery Energy Storage System
Traditionally, the power industry has contended that energy business is differentiated from every other entities and markets since it can’t be stored.
This has been essentially right, yet future advancements can possibly expel this notion and can consolidate storage with other grid matrix technologies to make a new Paradigm!
Electric batteries may offer the best potential as a smart grid enabler. Latest batteries are right now being conveyed to serve different forms of transmission and distribution applications, with different advantages possibly spilling out of a solitary establishment: Battery Energy Storage System.
Research continues to look for new technologies that will give the advancement in storage medium which will give a breakthrough in low cost storage medium for future utilities.
Battery Energy Storage Systems (BESS) Definition
A BESS is a type of energy storage system that uses batteries to store and distribute energy in the form of electricity.
These systems are commonly used in electricity grids and in other applications such as electric vehicles, solar power installations, and smart homes.
At its most basic level, a BESS consists of one or more batteries that store electrical energy for use at a later time. This stored energy can then be drawn upon when needed to meet various demands for power across different applications.
BESS can also provide advantages over other energy storage systems, including greater efficiency and flexibility, faster response times when powering equipment or devices, and lower costs overall.
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.
“ Battery Energy Storage System will become the core of home Energy Storage ”
Why BESS over other storage technologies
BESS has advantage over other Storage technologies as it has small footprint and no restrictions on 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 limited number of locations, considering water and siting-related restrictions and transmission constraints. Energy and power densities of some technologies are as follows:
Accordingly BESS utilizing Lithium Ion technology offer high energy and power densities that are suitable for utilizing at distribution transformer level. The available space at the distribution transformer setup can be used to locate the BESS.
The night peak that 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 are in the range of 160 kVA, 400kVA up to 1 MVA (for rural, urban and metropolitan respectively).
Therefore BESS only needs to supply a part of that capacity during maximum of 4 hours of peak time.
Following figure illustrates the places different technologies have in the space having the power, energy and discharge time as dimensions.
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 put in. 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 one 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 with 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 of 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 life time. 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
Parameters for determining the BESS economics
Many criterion 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 biggest deterministic factor for battery selection is the application which the BESS is required to service along with performance requirement management.
Aspects of Battery Energy Storage Systems’ 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 overall economics of the system.
Classification of BESS by Battery Types
BESSs intrinsically use electro-chemical solutions which manifest in some of the following Battery Types:
- 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.
- 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.
- Sodium Sulfur — uses include storing energy from renewable sources such as solar or wind.
- Zinc bromine — uses include storing energy from renewable sources such as solar or wind.
- Flow — flow batteries are quite large and are generally used to store energy from renewable sources.
Advanced Battery Technology Characteristics
Advanced Battery Technology Characteristics
There are various types of BESS available, depending on your needs and preferences.
Some common types include lithium-ion batteries, lead-acid batteries, flow batteries, and flywheels. Each type has its advantages and disadvantages in performance, lifespan, cost, and other factors.
- Lithium-Ion Batteries
These batteries are one of the most popular types of BESS. They offer a high energy density and are relatively lightweight, making them easy to transport and install.
- Lead-Acid Batteries
Lead-acid batteries are another common type of BESS. They are typically cheaper than lithium-ion batteries but have a shorter lifespan and are not as efficient.
- Flow Batteries
Flow batteries are a newer type of BESS that offer a longer lifespan than traditional lead-acid or lithium-ion batteries. They work by storing energy in an electrolyte solution, which can be redirected to different parts of the battery as needed.
Flywheels are another energy storage system that uses kinetic energy to store and release electricity. Flywheels are typically used for short-term storage applications, such as load leveling or backup power generation.
· National Energy Technology Laboratory, USA
· Lithium-ion Battery Energy Storage Systems, AIG Energy Industry Group