Abstract
Energy
storage plays a dynamic role in high-tech manufacturing where it is essential
to have an uninterruptable power source of constant frequency.
An energy storage system is able to take up a certain amount of energy in a controlled manner (charging), to contain this energy over a period of time relevant in the specific context and to release it over a period of time in a controlled manner (discharging).Energy storage is accomplished by devices or physical media that store some form of energy to perform useful operation at a later time. A device that stores energy is sometimes called an accumulator.
An energy storage system is able to take up a certain amount of energy in a controlled manner (charging), to contain this energy over a period of time relevant in the specific context and to release it over a period of time in a controlled manner (discharging).Energy storage is accomplished by devices or physical media that store some form of energy to perform useful operation at a later time. A device that stores energy is sometimes called an accumulator.
Source: https://i.ytimg.com/vi/3R7EzO3uBms/maxresdefault.jpg
Early History
Energy
storage as a natural process is as old as the universe itself. The energy
present at the initial formation of the universe has been stored in stars such
as the Sun, and is now being used by humans directly through solar heating or
indirectly (by growing crops or conversion into electricity in solar cells). In
the late nineteenth century, the processes of electrochemical energy storage
began to grow very rapidly. Large scale production of lead-acid batteries began
in 1880. Basically the world energy storage project began in 1988.
Storing energy allows humans to
balance the supply and demand of energy. Energy storage systems in commercial
use today can be broadly categorized as mechanical, chemical, electrical,
electrochemical, biological and thermal.
The key demands on an energy
storage system are high efficiency, low self-discharge, high capacity, high
number of charging and discharging cycles, high performance and low costs
coupled with a high degree of public acceptance.
Pumped Hydroelectric Storage
Pumped
hydroelectric storage offers a way to store energy at the
grid’s transmission stage, by storing excess generation for later
use. Many hydroelectric power plants include two reservoirs at different
elevations. These plants store energy by pumping water into the upper reservoir
when supply exceeds demand. When demand exceeds supply, the water is released
into the lower reservoir by running downhill through turbines to generate
electricity. Pumped Hydroelectric Storage power dominates the global and U.S.
energy storage markets, accounting for about 98 percent of installed storage
technologies. It has efficiency over 80% and inexpensive way to store energy.
But it has huge environmental impacts.
Compressed Air Energy storage
CAES systems
compress air using electricity during off-peak times, and then store the air in
underground caverns. During times of peak demand, the air is drawn from storage
and fired with natural gas in a combustion turbine to generate electricity.
Chemical energy storage
Hydrogen
can be used as a zero-carbon fuel for generation. A typical hydrogen
storage system consists of an electrolyzer, a hydrogen storage tank and a fuel
cell. An electrolyzer is an electrochemical converter which splits water with
the help of electricity into hydrogen and oxygen. To generate electricity, both
gases flow into the fuel cell where an electrochemical reaction which is the
reverse of water splitting takes place: hydrogen and oxygen react and produce
water, heat is released and electricity is generated. To a stabilization of the fluctuating electricity
production could be to have a significant capacity for gasification of
renewable resources (biomass and carbon containing waste fractions) in the
energy sector. Gasification is the reaction of carbonaceous raw materials with
steam at high temperature to produce syngas (mainly CO, CO2 and H2 ). the
syngas can in a range of catalytic processes be converted into various fuels
and chemicals (e.g. methane, methanol and synthetic gasoline and diesel)
Methane
can, typically with the use of a nickel catalyst, be produced from syngas by
hydrogenation of CO and CO2
CO
+ 3H2 → CH4 + H2O
CO2
+ 4H2 → CH4 + 2H2O
Methanol
can be produced from syngas by hydrogenation of CO and CO2 over a
copper based catalyst.
CO
+ 2H2 → CH3OH
CO2
+ 3H2 → CH3OH + H2O
Energy storage
technologies offer cost-effective flexibility and ancillary services needed by
the U.S power grid. As policy reforms and decreasing technology costs
facilitate market penetration, energy storage technologies offer increasingly
competitive alternative means for utilities to engage these ancillary services.
Superconducting magnet energy storage
Superconducting magnetic energy storage
systems store energy in the magnetic field created by the flow of direct
current in a superconducting coil. This advanced systems store energy within a
magnet and release it within a fraction of a cycle.
Electrochemical storage: Batteries
A battery is
a device that produces electrical energy from chemical reactions. Batteries are
an essential component in the development of a society based increasingly on
sustainable energy. There are many different types of batteries that have
large-scale energy storage potential, including sodium-sulfur, metal air,
lithium ion, and lead-acid batteries. Present day rechargeable
lithium-ion (Li-ion) batteries have been very successful since they were
commercialized around 1990 [9], largely due to their higher energy density
compared to competing battery chemistries like nickel-metal hydride (NiMH).
Biological Energy Storage
Living organisms use two major types of energy
storage. Energy-rich molecules such as glycogen and triglycerides store
energy in the form of covalent chemical bonds. Cells synthesize such molecules and store them for later
release of the energy.
Thermal Storage
Thermal
storage is used for electricity generation by using power from the
sun, even when the sun is not shining. Concentrating solar plants can capture
heat from the sun and store the energy in water, molten salts, or other fluids.
This stored energy is later used to generate electricity, enabling the use of
solar energy even after sunset. It has high efficiency comparative to other
storage systems.
Conclusion
Energy
storage is expensive, especially without policies that place a monetary value
on the unique benefits of storage. With the support of government and industry,
energy storage technologies can continue to develop and expand, aid in the
increasing deployment of variable renewable energy sources, and help store an
ever-growing amount of clean, renewable energy in the future. Storing large
amounts of energy will remain a great challenge in the next couple of years.
Pumped hydro plants are currently the only economical solution for this task
but capacities for new plants are limited or even completely utilized. Energy
storage is becoming a major concern in the global energy market and will
continue to grow for the foreseeable future. The Bangladeshi Government has set
a target to have 3,168 MW of renewable energy capacity installed by
2021.
References
Ø Union of Concerned Scientists. 2013.
http://www.ucsusa.org/assets/documents/clean_energy/Ramping-Up-Renewables-Energy-You-Can-Count-On.pdf.
Ø https://en.wikipedia.org/wiki/Energy_storage
Ø Denholm, P. et al. 2010. The role of energy
storage with renewable electricity generation. National Renewable
Electricity Laboratory. http://www.nrel.gov/docs/fy10osti/47187.pdf.
Ø Electricity Storage Association. 2013. Online
at: http://www.electricitystorage.org/
Ø Energy
Storage Activities in the United States Electricity Grid May 2011.
https://energy.gov/sites/prod/files/oeprod/DocumentsandMedia/FINAL_DOE_Report-Storage_Activities_5-1-11.pdf
Ø https://www.slideshare.net/ns90tnau/energy-storage
Ø Bangladesh
Plans Over 3 GW Renewable Energy Capacity By 2021 By Smiti Mittal
https://cleantechnica.com/2015/11/11/bangladesh-plans-3-gw-renewable-energy-capacity-2021/
