me165-1_week-10.2 energy storage tech

8/17/2019 ME165-1_Week-10.2 Energy Storage Tech

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ME165-1

ALTERNATIVE ENERGY RESOURCES

Engr. E

Week-10.2 Energy Storage Technologies2015-2016 / 3T


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Energy Storage Technologies

Overview of Energy Storage Energy storage will play a critical role in an efficient an

renewable energy future; much more so than it does in

fossil-based energy economy. There are two principal r

that energy storage will grow in importance with incre

development of renewable energy: Many important renewable energy sources are intermitt

generate when weather dictates, rather than when energ

dictates.

Many transportation systems require energy to be carrie

vehicle.


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Energy storage is accomplished by devices or physica

that store energy to perform useful operation at a laA device that stores energy is sometimes called an

accumulator.


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All forms of energy are either potential energy (e.g. Chemical,

gravitational, electrical energy, etc.) or kinetic energy (e.g. theenergy).

A wind-up clock stores potential energy (in this case mechanical, in t

tension), a battery stores readily convertible chemical energy, and a

dam stores energy in a reservoir as gravitational potential energy.

Ice storage tanks store ice (thermal energy) at night to meet peak d

cooling.

Fossil fuels such as coal and gasoline store ancient energy derived fr

by organisms that later died, became buried and over time were the

into these fuels.

Even food (which is made by the same process as fossil fuels) is a for

stored in chemical form.


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History

Energy storage as a natural process is as old as the universthe energy present at the initial formation of the universe

stored in stars such as the Sun, and is now being used by h

directly (e.g. through solar heating), or indirectly (e.g. by gr

crops or conversion into electricity in solar cells).

As a purposeful activity, energy storage has existed since pthough it was often not explicitly recognized as such. An e

deliberate mechanical energy storage is the use of logs or

defensive measures in ancient forts — the logs or boulders

collected at the top of a hill or wall, and the energy thus st

to attack invaders who came within range.


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History (cont’d.)

A more recent application is the control of waterwdrive water mills for processing grain or powering

machinery. Complex systems of reservoirs and da

constructed to store and release water (and the po

energy it contained) when required.


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Storage Methods

Mechanical Pumped-storage

Compressed-air storage

Flywheel storage

Electro chemical

Electrical battery storage

Electrical Superconducting magnetic energy storage

Thermal

Thermal sensible energy storage

Latent heat energy storage

Chemical

Chemical-reaction storage


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Pumped-Storage

The method stores energy in the form of potentia

water, pumped from a lower elevation reservoir to

elevation. Low-cost off-peak electric power is used

the pumps. During periods of high electrical deman

stored water is released through turbines to produelectric power.


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Pumped Storage (cont’d.)

The method stores energy in the form of potential energpumped from a lower elevation reservoir to a higher ele

Low-cost off-peak electric power is used to run the pum

periods of high electrical demand, the stored water is re

through turbines to produce electric power.


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Pumped Storage (cont’d.)


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Compressed-Air Energy Storage

Compressed-air energy storage (CAES) uses off pe

electricity to compress air into either an undergro

structure (e.g., a cavern, aquifer, or abandoned mine

above ground system of tanks or pipes.

The compressed air is then mixed with natural gas,

and expanded in a modified gas turbine. In a conve

turbine, roughly two thirds of the power produced

consumed in pressurizing the air before combustio


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Compressed-Air Energy Storage (cont’d.)

A compressed air locomotive

Porter, Inc., in use at the H

Mine between 1928 and 1961

A pressurized air tank used to start a

diesel generator set in Paris Metro


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Compressors use off-peak electricity to fill the cavern with compressed air. For peak demand, t

is withdrawn from the cavern and used to power a wind turbine. Credit: Ridge Energy Storage &


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CAES systems produce the same amount of electri

as a conventional gas turbine power plant using less

of the fuel.

Recent advancements in the technology include abo

ground storage in empty natural gas tanks and ‘mintransportable technology that can be installed at or

individual loads (e.g., on urban rooftops).

http://www.youtube.com/watch?v=dGd7PIC09AM

http://www.youtube.com/watch?v=dGd7PIC09AMhttp://www.youtube.com/watch?v=dGd7PIC09AM


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Flywheel Energy Storage

Flywheel energy storage (FES) works by accelerating a rotor

to a very high speed and maintaining the energy in the system

rotational energy.

When energy is extracted from the system, the flywheel's ro

speed is reduced as a consequence of the principle of conser

energy; adding energy to the system correspondingly results increase in the speed of the flywheel.

Most FES systems use electricity to accelerate and decelerat

flywheel, but devices that directly use mechanical energy are

developed.

http://www.mashpedia.com/videoplayer.php?q=u6I2

http://www.mashpedia.com/videoplayer.php?q=u6I2lKtfpLQhttp://www.mashpedia.com/videoplayer.php?q=u6I2lKtfpLQ


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Flywheel Energy Storage (cont’d.) http://www.youtube.com/watch?v=ACmXhttp://www.youtube.com/watch?v=ay_

http://www.youtube.com/watch?v=ACmXLLqTnSshttp://www.youtube.com/watch?v=ay_NiGu7mishttp://www.youtube.com/watch?v=ay_NiGu7mishttp://www.youtube.com/watch?v=ACmXLLqTnSs


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Flywheel energy storage (cont’d.)

Advanced FES systems have rotors made ofhigh strength carbon filaments, suspended

by magnetic bearings, and spinning at

speeds from 20,000 to over 50,000 rpm in

a vacuum enclosure. Such flywheels can

come up to speed in a matter of minutes — much quicker than some other forms of

energy storage.NASA G

http://www.youtube.com/watch?v=mV_b5oMqc2

http://www.youtube.com/watch?v=mV_b5oMqc2Mhttp://www.youtube.com/watch?v=mV_b5oMqc2M


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Electrical battery storage

An electrical storage battery allowselectrical energy to be converted

into chemical energy, stored, and

converted back to electrical energy.

Batteries are made up of three basic

parts: a negative electrode, positiveelectrode, and an electrolyte (see

schematic below).


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Electrical battery storage (cont’d.)

The negative electrode gives up electrons to an ex

load,and the positive electrode accepts electrons f

load.

The electrolyte provides the pathway for charge to

between the two electrodes. Chemical reactions between each electrode and th

electrolyte remove electrons from the positive ele

and deposit them on the negative electrode.


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This can be written as an overall chemical reaction

represents the states of charging and discharging o

battery.

The speed at which this chemical reaction takes pl

related to the internal resistance that dictates the power at which the batteries can be charged and d


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Lead-Acid

It is one of the oldest and most mature battery

technologies. In its basic form, the lead – acid batte

consists of a lead (Pb) negative electrode, a lead d

(PbO2) positive electrode and a separator to elecisolate them. The electrolyte is dilute sulfuric acid

which provides the sulfate ions for the discharge


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Lithium-Ion

Lithium-ion and lithium polymer batteries, althoug

primarily used in the portable electronics market,

to have future use in many other applications. The

in these batteries is a lithiated metal oxide (LiCoOLiMO2, etc.) and the anode is made of graphitic c

with a layer structure. The electrolyte consists of

salts (such as LiPF6) dissolved in organic carbonat


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Nickel-Cadmium (NiCd) Nickel-Metal Hydride (NiMH)

Sodium Sulfur (NaS)

Zebra or Sodium-Nickel-Chloride (NaNiCl)


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Superconducting magnetic energy storage

A superconducting magnetic energy storage (SMEis well suited to storing and discharging energy at h

(high power.)

It stores energy in the magnetic field created by di

current in a coil of cryogenically cooled, supercondmaterial. If the coil were wound using a convention

such as copper, the magnetic energy would be diss

heat due to the wire’s resistance to the flow of cur

http://www.youtube.com/watch?

http://www.youtube.com/watch?v=QU05d43dw6ghttp://www.youtube.com/watch?v=QU05d43dw6g


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SMES (cont’d.)

The advantage of a cryogenically cooled, supercondmaterial is that it reduces electrical resistance to a

zero.

The SMES recharges quickly and can repeat the

charge/discharge sequence thousands of times withdegradation of the magnet. A SMES system can ach

power within 100 ms.


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SMES (cont’d.)

Theoretically, a coil of around 150 – 500 m radius w

able to support a load of 18,000 GJ at 1000 MW, d

on the peak field and ratio of the coil’s height and

diameter.Recharge time can be accelerated to mee

requirements, depending on system capacity.


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SMES (cont’d.)

SMES systems have the following parts - superconducting coilconditioning system, cryogenically cooled refrigerator, cryosta

vessel.


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SMES (cont’d.)

In an SMES system, because the electrical current has zerothe magnetic field once created will almost never be weak

the system breaks itself. So, compared to other systems, it

least amount of energy during storage making them very e

They are also highly reliable because major components in

motionless. The most important feature of SMES is that the time it tak

charge and discharge is very short. Right now, SMES system

mainly used to improve power quality.


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Direct Thermal Storage

Direct thermal technologies, although they are storlower grade of energy (heat, rather than electrical

mechanical energy) can be useful for storing energ

systems that provide heat as a native output (e.g., s

thermal, geothermal), or for applications where thecommodity value is heat (e.g., space heating, drying


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Direct Thermal Storage (cont’d.)


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Direct Thermal Storage (cont’d,)

Although thermal storage technologies can be charby specific energy and energy density like any other

technology, they can also be characterized by an im

additional parameter: the delivery temperature rang

Different end uses have more or less allowance forswings of the delivery temperature. Also, some app

require a high operating temperature that only som

storage media are capable of storing.


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Direct Thermal Storage (cont’d,)

Thermal storage can be classified into two fundamecategories: sensible heat storage and latent heat sto

Applications that have less tolerance for temperatur

should utilize a latent heat technology.


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Sensible heat is the heat that is customarily and associated with a change in temperature of a mass

substance.

Substances with the ability to absorb heat energy w

relatively small increase in temperature (e.g., waterhigh specific heat, whereas those that get hot with

little heat input (e.g., lead) have a low specific heat.

Sensible heat storage is best accomplished with ma

having a high specific heat.


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Latent heat is absorbed or liberated by a phase cchemical reaction and occurs at a constant tempera

A phase change means the conversion of a homoge

substance among its various solid, liquid, or gaseous

One very common example is boiling water on thethough a substantial amount of heat is absorbed by

in the pot, the boiling water maintains a constant

temperature of 100oC.


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Chemical Reaction Change

A wide variety of reversible chemical reactions are available tand absorb heat.

The principal feature of this category of latent heat storage

technologies is the ability to operate at extremely high tempe

some cases over 900oC.

Extremely high temperature applications have focused primarfossil and advanced nuclear applications; to date, none of thes

methods of heat storage have been deployed in commercial r

energy applications.


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Hydrogen

Hydrogen is also being developed as an electrical pstorage medium.

Hydrogen is not a primary energy source, but a po

energy storage method, because it must first be

manufactured by other energy sources in order to However, as a storage medium, it may be a significa

in using renewable energies.


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Hydrogen (cont’d.)

Utility scale underground liquid hydrogen storage

http://www.youtube.com/watch?v=c2yraQkMsJ

http://www.youtube.com/watch?v=c2yraQkMsJshttp://www.youtube.com/watch?v=c2yraQkMsJs


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Hydrogen (cont’d.)

Underground hydrogen storage is the practice of hydrogeunderground caverns, salt domes and depleted oil and gas

quantities of gaseous hydrogen are stored in underground

many years without any difficulties.

The storage of large quantities of hydrogen underground

as grid energy storage which is essential for the hydrogen By using a turboexpander, the electricity needs for compr

storage at 200 bars amounts to 2.1% of the energy conten


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Textbooks Renewable Energy Technologies, Jean-Claude Sabonnadiere, 2009

Energy Conversion, D. Yogi Goswami, Frank Kreith, 2008

Power Plant Engineering, 3rd Edition, PK Nag, 2008, Tata McGraw

Web

http://en.wikipedia.org/wiki/Energy_storage http://en.wikipedia.org/wiki/Compressed-air_energy_storage

References
http://en.wikipedia.org/wiki/Fuel_cellhttp://en.wikipedia.org/wiki/Fuel_cellhttp://en.wikipedia.org/wiki/Compressed-air_energy_storagehttp://en.wikipedia.org/wiki/Compressed-air_energy_storagehttp://en.wikipedia.org/wiki/Compressed-air_energy_storagehttp://en.wikipedia.org/wiki/Compressed-air_energy_storagehttp://en.wikipedia.org/wiki/Fuel_cell

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