S R Awasthi
Consultant, CECL, Bhopal
Ex. General Manager, BHEL
Dr. Pragya Nema
Professor, Electrical Engineering Department
Netaji Subhash Engineering College, Kolkata (W.B.)

• Introduction
• Background of storage system
• Different energy storage technology
• Comparison of different storage technology
• Conclusion

• What is energy storage system for renewable energy ?
• Why is it required ?
• Function of energy storage system

Storage is an essential unit that stores unstable electric energy during wind and photovoltaic power generation, which is sharply growing new renewable energy, and supplies the unstable energy to electric power system again in necessary moment. If there is no such energy storage unit, any kinds of serious problems like sudden blackout occurs because of unstable sunlight-dependent electricity supply. This
Storage takes an important part in the electricity storage systems for households, the medium-size system for industrial/commercial use, and the extralarge system for power plants and substations like
Frequency Regulations

DIFFERENT ENERGY STORAGE
TECHNOLOGIES
• Pumped storage
• Batteries
• Superconducting magnet energy storage
• Flywheel energy storage
• Regenerative fuel cell storage
• Compressed air energy storage

• A pumped storage hydro power plant may store huge energy by pumping water from a lower reservoir to a higher pond. In a pumped storage hydro plant, we usually make the height of the reservoir equal to a small hill and at bottom a cavity is made so that water may not run away downward.
• Water is pumped during off-peak times and may be utilized to generate electricity. Other innovations may store electricity in small quantity but pumped storage hydro power plant may store electricity in Megawatts (MW) or even
Gigawatts(GW).

Battery working
Battery
Battery Bank

• Flywheel energy storage systems are one of energy storage devices. They store energy mechanically in the flywheel rotor by rotating the rotor while as chemical batteries stores energy electrically. When we want to use the stored energy in the rotor, a generator is used to convert mechanical energy to electrical energy.
• Flywheel systems are not sensitive to temperature since they are operating in a vacuum containment. Therefore, the hybrid vehicle with flywheel systems can run without any problem at very cold or hot areas. And, flywheel systems can store more energy per system weight compared to chemical batteries,
• The flywheel system is a very efficient energy storage device, it can be used for various applications.

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.

• A fuel cell is an electrochemical cell that converts a source fuel (from combustible substances such as hydrogen, methane, propane, and methanol) into an electric current.
• A fuel cell is a device that generates electricity by a chemical reaction. Every fuel cell has two electrodes, one positive and one negative, called, respectively, the anode and cathode. The reactions that produce electricity take place at the electrodes.
•
• Hydrogen is the basic fuel, but fuel cells also require oxygen. One great appeal of fuel cells is that they generate electricity with very little pollution—much of the hydrogen and oxygen used in generating electricity ultimately combine to form a harmless byproduct, namely water.

continue…
• Energy from solar or wind and even electricity from thermal power plant during off-peak period may be utilized to compress air by compressor and same air may be utilized to produce electricity during peakhour.
• Compressed air energy storage is done in underground caverns and abandoned mines.

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