The document outlines a course focused on understanding various energy storage systems, covering topics such as thermal storage, battery technologies, fuel cells, and alternative energy storage methods. It highlights the importance of energy storage for managing intermittent renewable energy sources and discusses the applications and efficiencies of different storage technologies. Additionally, it compares energy storage systems based on their technical maturity, cycle efficiency, and environmental impact.

1. EE 3032-ENERGY STORAGE
SYSTEMS

2. COURSE OBJECTIVES
• Students will be able to
• understand the various types of energy
storage Technologies.
• analyze thermal storage system. analyze

different battery storage technologies
• analyze the thermodynamics of Fuel Cell
• study the various applications of energy
storage systems

3. SYLLABUS
• UNIT I INTRODUCTION
• Necessity of energy storage – types of energy storage – comparison of
energy storage technologies – Applications. UNIT II THERMAL STORAGE
SYSTEM
• Thermal storage – Types – Modeling of thermal storage units – Simple water
and rock bed storage system – pressurized water storage system – Modelling
of phase change storage system – Simple units, packed bed storage units -
Modelling using porous medium approach, Use of TRNSYS.
• UNIT III ELECTRICAL ENERGY STORAGE
• Fundamental concept of batteries – measuring of battery performance,
charging and discharging, power density, energy density, and safety issues.
Types of batteries – Lead Acid, Nickel – Cadmium, Zinc Manganese dioxide,
Li-ion batteries - Mathematical Modelling for Lead Acid Batteries – Flow
Batteries.

4. SYLLABUS
• UNIT IV FUEL CELL
• Fuel Cell – History of Fuel cell, Principles of Electrochemical
storage – Types – Hydrogen oxygen cells, Hydrogen air cell,
Hydrocarbon air cell, alkaline fuel cell, detailed analysis –
advantages and disadvantages.
• UNIT V ALTERNATE ENERGY STORAGE TECHNOLOGIES
Flywheel, Super capacitors, Principles & Methods –
Applications, Compressed air Energy storage, Concept of
Hybrid Storage – Applications, Pumped Hydro Storage –
Applications.

5. ENERGY STORAGE TECHNOLOGIES FOR
INTERMITTENT RENEWABLE ENERGY
SYSTEMS

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

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

8. Background of 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 extra-large
system for power plants and substations like Frequency
Regulations

9. use of ES systems
• reduced energy costs;
• reduced energy consumption;
• improved indoor air quality;
• increased flexibility of operation;
• reduced initial and maintenance costs.
• reduced equipment size;
• more efficient and effective utilization of equipment;
• conservation of fossil fuels (by facilitating more efficient energy
use and/or fuel substitution);
• reduced pollutant emissions (e.g., CO2 and chlorofluorocarbons
(CFCs)).

10. ES applications
• • Utility. Relatively inexpensive base-load electricity can be used to charge ES systems
during evening or off-peak weekly or seasonal periods. The electricity is then used
during peak periods, reducing the reliance on conventional gas and oil peaking
generators.
• • Industry. High-temperature waste heat from various industrial processes can be
stored for use in preheating and other heating operations.
• • Cogeneration. Since the closely coupled production of heat and electricity by a
cogeneration system rarely matches demand exactly, excess electricity or heat can be
stored for subsequent use.
• • Wind and run-of-river hydro. Conceivably, these systems can operate around the
clock, charging an electrical storage system during low-demand hours and later using
that electricity for peaking purposes. ES increases the capacity factor for these
devices, usually enhancing their economic value.
• • Solar energy systems. By storing excess solar energy received on sunny days for use
on cloudy days or at night, ES systems can increase the capacity factor of solar energy
systems.

12. DIFFERENT ENERGY STORAGE
TECHNOLOGIES
• Mechanical ES
• (i) Hydro storage(Pumped storage)
• (ii)Compressed air Storage
• (iii) Flywheel energy storage
• Batteries(Electro Chemical Storage)
• Superconducting magnet energy storage
• Regenerative fuel cell storage
• Compressed air energy storage

13. Pumped 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).

14. Off peak period- pumping uphills (pump) powered by
solar-day
Peak period- down pumping(turbine) –night
50% efficiency

15. The primary criteria for location are the geological conditions for the lower
reservoir. The subsurface material should be of solid hard rock, and should not
be located in areas that have
• predominantly loose sedimentary rock;
• volcanic rock;
• complex geological structures with widely varying conditions over short
distances;
• high seismic activity; or
• major faults.

16. Compressed air storage
Off peak – air compressed (reservoir)
underground cavern-no environment impact
Peak period-releases gas (gas turbine generator)
1. Sliding pressure- store
increases, pr inc
2. Compensated pr- external force
to maintain const pr

17. Compressed air energy storage
ntinue…
•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 peak-
hour.
•Compressed air energy storage is done in
underground caverns and abandoned
mines.

19. Flywheel energy storage
• 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.
Off peak-
spinning (KE)

21. • Transportation- road vehicle-frequent
start/stop
• Deceleration- stores KE in spinning
• Regenerative braking- power train- from
wheel, generated energy is stored in battery
• Less heat dissipation
• Less efficiency
1 whhr /1.8 kg/2m dia/600
rpm
Regenerative braking captures energy that is otherwise
lost during braking and then uses this power to help
recharge the vehicle's battery.

22. • Some research and development areas in the field
of flywheel ES are as follows:
• • development of high-speed, low-cost manufacturing
methods for composite rotors and hubs having high
specific energy densities;
• • development and experimental evaluation of novel
composite rotor concepts (e.g., elastomeric matrix and
elastomeric interlayer);
• • evaluation of the durability of new composite rotor
materials, considering properties such as fatigue and creep.

23. 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.

24. •

26. Thermal Energy Storage

28. Example- S TES

32. Covective Loss

34. Example-L TES

35. Chemical Energy Storage
• Energy may be stored in systems composed of
one or more chemical compounds that release
or absorb energy when they react to form
other compounds
• Hydrogen, Hydrogen as a fuel
• Aluminium

38. Battery Bank
Battery
Battery working
Electro Chemical Storage- Batteries

39. Regenerative fuel cell storage
• 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.
•

41. • Batteries chemically store energy and release it as
electric energy on demand.
• Batteries are a stable form of storage and can provide
high energy and power densities, such as those
needed for transportation.
• There are three main categories of energy
applications for which batteries are potentially
attractive: electric utility load management, electric
vehicles, and storage for renewable energy systems
(e.g., photovoltaic and wind systems).
Battery

42. electric utility load management
• The compressed-air option could meet the
needs for electricity generation over an 8–12
h period
• while a battery facility may suffice only over a
3–5 h period.

43. • The amount of energy that can be stored in a
battery is called its capacity.
• measured in amp hours (Ah). A 100-Ah battery will
deliver 1 A of current for 100 h, or 4 A for 25 h.
• although battery capacity will decrease with
increasing discharge rates.
• Battery capacities ranging from 1 to 2000 Ah or
more are available.
• If more than half the battery’s stored energy is
discharged before it is recharged, this is called deep
cycling

44. Lifetime Cycle:
The cycle life of batteries is the number of charge and discharge cycles that a
battery can complete before losing performance.

45. Measure of Merit
• Specific energy (or specific ES).(Range)
• The amount of energy stored per unit weight or
mass of a storage technology in a particular
vehicle application (often measured in Wh/kg)
• Energy density.(Size)
• The total amount of energy a battery can store
per liter of its volume for a specified rate of
discharge (Wh/L or Wh/m3 ). High energy density
batteries have a smaller size

46. • Specific power or power density.(Acceleration)
The rate of energy delivery or power for the
storage per weight or mass of a storage
technology in a particular vehicle application
(often measured in W/kg).
• Specific power is at its highest when the battery
is fully charged.
• Cycle life. The cycle life is total number of times a
battery can be discharged and charged during its
life. When the battery can no longer hold a
charge over 80%, its cycle life is considered
finished. electrode and electrolyte deterioration,
which determines the life of the battery

47. • Battery cost. This economic factor is
expressed in dollars per kilowatt-hour
($/kWh)

48. https://www.youtube.com/watch?v=rBTisilsh7Q

52. Biological ES
• Biological storage is the storage of energy in
chemical form by means of biological
processes and is considered an important
method of storage for long periods of time.

53. Comparison of ESS

54. • ESD- Energy storage density
• MPD0Maximum power density
• MSP-Max Specific power
• SE- Specific Energy
• CSL-Charged shell life
• TDT-Typical discharge time
• UL-useful life
• AA-Application area
• EU-Electric utility
• ES-Emergency service for electric power failure

55. • SLI – Automative starting, lighting and ignition
• RB-regenerative braking
• RH-residential heating
• SA-Specific Applications
• AP- automative Propulsion

57. Assessment and comparison of the energy
storage technologies
PEA3450 – Disciplina: Coleta e Armazenamento de Energia
57 PEA3450 – Disciplina: Coleta e Armazenamento de Energia
57
• Technical maturity
1. Mature technologies: PHS and lead-acid battery are
mature and have been used for over 100 years.
2. Developed technologies: CAES, NiCd, NaS, ZEBRA Li-
ion, Flow Batteries, SMES, flywheel, capacitor,
supercapacitor, Al-TES (Aquiferous low- temperature –
Thermal energy storage) and HT-TES (High
temperature – Thermal energy storage) are developed
technologies.
3. Developing technologies: Fuel cell, Meta-Air battery,
Solar Fuel and CES (Cryogenic Energy Storage) are still
under development

59. 59
 Power rating and discharge time

60. Storage duration
Table 1 also illustrates the self-discharge (energy
dissipation) per day for EES systems. One can see that
PHS, CAES, Fuel Cells, Metal-Air Cells, solar fuels and
flow batteries have a very small self-discharge ratio so
are suitable for a long storage period. Lead-Acid, NiCd,
Liion, TESs and CES have a medium self-discharge
ratio and are suitable for a storage period not longer
than tens of days .
NaS, ZEBRA, SMES, capacitor and supercapacitor have
a very high self-charge ratio of 10–40% per day. They
can only be implemented for short cyclic periods of a
maximum of several hours.

61. 61
• Capital cost

62. • Cycle efficiency
One can see that the EES systems can be broadly divided into
three groups:
1. Very high efficiency: SMES, flywheel, supercapacity and Li-ion
battery have a very high efficiency of > 90%.
2. High efficiency: PHS, CAES, batteries (except for Li-ion), flow
batteries and conventional capacitor have a cycle efficiency of
60–90%.
3. Low efficiency: Hydrogen, DMFC, Metal-Air, solar fuel, TESs
and CES have an efficiency lower than ~60% mainly due to
large losses during the conversion from the commercial AC
side to the storage system side.
• DMFC-direct methanol fuel cell ,

63. Energy and Power Density

64. Life time and cycle life
Also compared in Table 1 are life time and/or cycle life for
various EESs. It can be seen that the cycle lives of EES systems
whose principles are largely based on the electrical technologies
are very long normally greater than 20,000. Examples include
SMES, capacitor and supercapacitor. Mechanical and thermal
energy storage systems, including PHS, CAES, flywheel, AL-TES,
CES and HT-TES, also have long cycle lives.
These technologies are based on conventional mechanical
engineering, and the life time is mainly determined by the life
time of the mechanical components. The cycle abilities of
batteries, flow batteries, and fuel cells are not as high as other
systems due to chemical deterioration with the operating time

65. • There is obviously a cost associated to storing energy, but we
have seen that, in many cases, storage is already cost
effective. More and more application possibilities will emerge
as further research and development is made in the field [91].
• Coupled with local renewable energy generation,
decentralized storage could also improve power network
sturdiness through a network of energy farms supplying a
specific demand zone.
• Each EES system has a suitable application range. PHS, CAES,
large-scale batteries, flow batteries, fuel cells, solar fuels, TES
and CES are suitable for energy management application;
flywheels, batteries, capacitors and supercapacitors are more
suitable for power quality and short duration UPS, whereas
batteries, flow batteries, fuel cells and Metal-Air cells are
promising for the bridging power.

66. • PHS and Lead-Acid battery are technically mature; CAES,
NiCd, NaS, ZEBRA Li-ion, flow battery, SMES, flywheel,
capacitor, Supercapacitor, AL-TES and HT-TES are technically
developed and commercially available; Fuel Cell, Meta-Air
battery, Solar Fuel and CES are under development.
• The cycle efficiencies of SMES, flywheel,
capacitor/supercapacitor, PHS, CAES, batteries, flow batteries
are high with the cycle efficiency above 60%. Fuel Cell, DMFC,
Metal-Air, solar fuel, TES and CES have a low efficiency mainly
due to large losses during the conversion from commercial AC
to the storage energy form.

67. • The cycle abilities of batteries, flow batteries, and fuel cells
are not as high as other systems due to chemical
deterioration with the operating time. Metal-Air battery has
the lowest life time at least currently.
• PHS, CAES, batteries, flow batteries, fuel cells and SMES are
considered to have some negative effects on the environment
due to one or more of the following: fossil combustion, strong
magnetic field, landscape damage, and toxic remains. Solar
fuels and CES are more environmentally friendly. However, a
full life-cycle analysis should be done before a firm conclusion
can be drawn.

68. • The development of storage techniques requires the improvement and
optimization of power electronics, often used in the transformation of
electricity into storable energy, and vice versa.
• The rate of penetration of renewable energy will require studies on the
influence of the different storage options, especially those
decentralized, on network sturdiness and overall infrastructure and
energy production costs.
• It is important to assess the national interest for compressed gas storage
techniques.
• Investment in research and development on the possibility of combining
several storage methods with a renewable energy source will lead to the
optimization of the overall efficiency of the system and the reduction of
greenhouse gases created by conventional gas-burning power plants.

69. • The development of supercapacitors will lead to
their integration into the different types of usage.
• The development of low-cost, long-life flywheel
storage systems will lead to increased potential,
particularly for decentralized applications.
• To increase the rate of penetration and use of
hydrogen-electrolysor fuel-cell storage systems, a
concerted R&D effort will have to be made in this
field.

70. References
• Milborrow, D., 2000, “Trading Rules Trap Wind in the Balance,” Windpower Monthly, Vol. 16, pp 40-43.
• Cavallo, A. 1995, “High Capacity Factor Wind Energy Systems,” J. Solar Energy Eng., Vol. 117, pp 137-143.
• Schainker, R., 1996, private communication, Electric Power Research Institute, Palo Alto, CA, presented at the
PowerGen Conference, Orlando, FL USA.
• Innogy PLC, 2001, Innogy Technology Ventures Ltd., Harwell International Business Center, Harwell,Didcot OX11
0QA (www.innogy.com).
• Cavallo, A., 1996, Storage System Size as a Function of Wind Speed Autocorrelation time for a Wind Energy
Baseload System, Proceedings of the European Wind Conference, Goeteborg, Sweden, pp 476-479.
• Schainker, R.B., Mehta, B. and Pollak, R., 1993, Overview of CAES Technology, Proceedings of the American Power
Conference, Chicago, IL, Illinois Institute of Technology, pp 992-997.
• Ter-Garzarin, A, Energy Storage for Power Systems, Chapter 7, IEEE, London, UK, Peter Pergrinus Ltd.Redwood
Books, Trowbridge, Wiltshire, UK.
• Obert, E.F., “Thermodynamics,” McGraw-Hill, New York, London, Toronto, pp 478-490.
• Nakhamkin, M., Swensen, E., Abitante, P, Schainker, R and Pollak, R., 1993, Technical and Economic Characteristics
of Compressed Air Energy Storage Concepts with Air Humidification, Proceedings of the American Power
Conference Chicago, IL, Illinois Institute of Technology, pp 1004-1009.
• Cavallo, A., and Keck, M., 1995, Cost Effictive Seasonal Storage of Wind Energy, SED-Vol 16, Wind Energy, Editors,
W.D. Musial, S.M. Hock, E. Berg, Book No. H00926-1995, pp 119-125.
• De Laquill III, P., Kearney, D., Geyer, M., and Diver, R. Solar Thermal Electric Technology,” 1993,
• Renewable Energy: Sources for Fuels and Electricity, T.B. Johannson, H. Kelly, A.K. Reddy and R.H.Williams, eds.,
Island Press, Washington, DC.