Energy, Enviroment and Society - Energy Storage

Prepared By:Sagar Mali (2067/BEX/133)Sanid Prajapati (2067/BEX/134)

ENERGY STORAGE

Presented By:Rasu Shrestha (2067/BEX/131)Raushan Mahaseth (2067/BEX/132)Saugat Gautam (2067/BEX/135)

Accumulation of energy for future useAccomplished by devices or physical media that

stores energySuch devices are also known as AccumulatorsTo balance the supply and demand of energyMajor categories are:

MechanicalElectricalChemicalBiologicalThermal

INTRODUCTION

1. Smart Grid Systems2. Batteries3. Super Capacitors

Energy storing System & Devices

Modernized and intelligent electrical network Various energy sources are integrated into single gridActs according to available information & communication

technologyInformation gathered may be:

Behaviors of suppliers and consumersTotal energy generatedTotal use of energyDisturbances and problems within grid

Currently implemented among European countries

1. Smart Grid Systems

System Overview

ReliabilityFault detectionSelf healing

Flexibility in network topologyDistributed generation (from hydropower, solar cells, wind

turbines etc)Bidirectional energy flow (charging to/from batteries from

electric car)Efficiency

Storing energy in off-peak timeSmart appliances

SustainabilityUse of renewable energy sourcesAuto monitor and control system

Features of the smart grid

Energy storing device based upon the principle of Electro-Chemical Reaction

Converts stored chemical energy directly into electrical energy

Every battery consists of Cathode (+ve terminal)Anode (-ve terminal)Electrolyte (medium for ions)

2. Batteries

Each cell is divided to two parts:Half cell of cathode and electrolytesHalf cell of anode and electrolytes

Cations are reduced (e- are added) at the cathode during chargingAnions are oxidized (e- are removed) at the anode during dischargeBasically, Redox reaction powers the batteryEach half-cell has an Electromotive force (emf), determined

by its ability to drive electric current from the interior to the exterior of the cell

The net emf is the difference between the reduction potentials of the half-reactions

Principle of Operation

1. Primary Batteries Disposable batteries (can’t be recharged) because

• Chemical reactions are not easily reversible• Materials may not return to their original forms

Can produce current immediately on assembly Most commonly used in portable devices Used well away from an alternative power source Ex: Zinc–Carbon batteries and Alkaline batteries

Types of Batteries

2. Secondary Batteries Rechargeable batteries as chemical reaction are reversible Charged by applying electric currentUsed for power backup as well as in portable devices Example

Wet cell: Lead- acid batteriesDry cell: NiMH, NiCad, Li-ion etc.

Types of Batteries

3. Super-capacitors

• A type of electromechanical capacitors• Formerly known as Electric Double-Layer Capacitor

(EDLC) or Ultra-capacitors• Doesn’t have a conventional solid dielectric• Can store huge amount of electrical energy

(more energy per unit volume)

Energy Storage Mechanism• Store electrical charge in an electric double layer at the

interface between high-surface-area carbon electrode and liquid electrolyte.

• Double layers are of same substrate and have vanishingly thin (~nm)

• These layers can handle only small P.D so super-capacitors have to be connected in series to operate in high P.D.

• No need of dielectric layer permits packing of plates with large area into given size resulting in high capacitances.

Comparison of Conventional Storage Technologies

Applications

• Stabilizing the supply of power lines.• Provides emergency backup to low power devices such

as RAM, S-RAM , Microcontrollers andPC cards in industries.

• Delivers power for photographic flashes in digital cameras.

• Super-capacitors are used as battery replacement in some pit trains in China to substitute conventional trolleys in coal mines. They bring coal to the surface.

Super-capacitors as Green Electricity

• Does not contain harmful chemicals for storing charge. Hence, safe to human.

• High number of charge-discharge lifecycle makes sure of less number of disposable parts makes it environmentally friendly.

Benefits

• Very high rates of charging and discharging.• Little degradation over hundreds of thousands of cycle.• Good reversibility.• Low toxicity of materials used.• High cycle efficiency( 95% and more).

Limitations

• The amount of energy stored per unit weight is considerably lower than that of an electrochemical battery.

• The voltage varies with the energy stored. To effectively store and recover energy requires sophisticated electronic control and switching equipment.

• Has the highest dielectric absorption of all types of capacitors.

Websites:http://en.wikipedia.org/wiki/Energy_storagehttp://en.wikipedia.org/wiki/Smart_gridhttp://

science.howstuffworks.com/environmental/green-science/smart-grid.htm

http://file.scirp.org/Html/2-6201335/e2908f91-a50c-49e9-a24f-a23192a753fc.jpg

http://en.wikipedia.org/wiki/Battery_(electricity)http://electronics.howstuffworks.com/everyday-tech/battery1.

htm

REFERENCES

THANK YOU!