This document provides an overview of energy storage technologies and innovation. It discusses the need for energy storage to balance electricity supply and demand from renewable sources. It describes various energy storage technologies including batteries, pumped hydroelectric storage, compressed air energy storage, thermal storage, and hydrogen storage. Case studies of existing pumped hydro, thermal, and flywheel energy storage projects are presented. The future of energy storage systems is seen to involve a mix of technologies with batteries and pumped hydro playing a large role.

1. Energy Storage
Technologies & Innovation
Presented by:
Mohamed Ahmed Zein
Mostafa Ahmed Zein
Faculty Of Engineering – Ain Shams University

2. Contents
Sustainable Development06
Why we need it?02
Energy Storage Technologies03
Case Studies04
The Future of ESS05
What is Energy Storage?01

3. Discussion

4. What is ESS?1

5. What is ESS?
• Energy storage is the capture of energy produced at one time for use at a later time.
• Can be applied to both Conventional sources of electricity and Renewable energy.
• Some technologies provide short-term energy storage, while others can endure for much longer.
1

6. Why ESS is Needed?
• The electricity grid is a complex system in which power supply and demand must be equal at any
given moment.
• Some renewable energy technologies – such as wind and solar – have variable outputs, storage
technologies have great potential for smoothing out the electricity supply from these sources.
• Energy storage is also valued for its rapid response – most storage technologies can begin
discharging power to the grid very quickly, while fossil fuel sources tend to take longer to ramp up.
• Energy storage also becomes more important the farther you are from the electrical grid.
2

7. How to Store Energy
1. Flywheels
2. Superconducting Magnetic Energy Storage (SMES)
3. Batteries
I. Lead-Acid Batteries
II. Lithium-Ion Batteries
III. Other batteries in Development
4. Pumped Storage Hydroelectricity (PSH)
5. Compressed Air Energy Storage (CAES)
6. Power To Gas (P2G)
7. Thermal Storage
8. Hydraulic Hydro Energy Storage (HHS)
3

8. Flywheels
The spinning speed for a modern single flywheel reaches up
to 16,000 rpm and offers a capacity up to 25 kilowatt hours
(kWh), which can be absorbed and injected almost instantly.
Advantages Disadvantages
Low maintenance and long
lifespan: up to 20 years
High self-discharge (3 –20
percent per hour)
Almost no carbon emissions Low storage capacity
Fast response times High acquisition costs
No toxic components
3.1

9. Flywheels3.1

10. Superconducting Magnetic Energy Storage
The idea is to store energy in the form of an electromagnetic field
surrounding the coil, which is made of a superconductor
At very low temperatures, some materials lose every electric
resistance and thus become superconducting
Advantages Disadvantages
Capable of partial and deep
discharges
High energy losses (~12 percent
per day)
Fast Response time
Very expensive in production and
maintenance
No environmental hazard
Reduced efficiency due to the
required cooling process
3.2

11. Batteries3.3
• A battery is a device that produces electrical energy from chemical reactions. There are
different kinds of batteries with different chemicals.
• The idea behind them is that the two different chemicals within a battery cell have different
loads and are connected with a positive (cathode) and the other with a negative electrode
(anode). When connected to an appliance the negative electrode supplies a current of
electrons that flow through the appliance and are accepted by the positive electrode.

12. Lead-Acid Batteries3.3.I
• The lead-acid battery is the oldest known type of rechargeable battery and was invented in
1859
• A lead-acid battery usually has several in-series connected cells, each delivering 2 volts (V)
and each consisting several spongy pure lead cathodes, positive loaded lead oxide anodes
and a 20 –40 percent solution of sulfuric acid that acts as an electrolyte.
Advantages Disadvantages
Easy and therefore cheap to produce Very heavy and bulky
Easily recyclable Rather short lived
Very high surge-to-weight-ratio; capable of delivering
a high jolt of electricity at once, which is why they are
so suitable as car starters
Environmental concerns: although safe, lead is very
toxic, and exposure can cause severe damage to
people and animals
Mature technology, more than 150 years of
experience and development
Corrosion caused by the chemical reactions

13. Lithium-Ion Batteries3.3.II
Lithium is the lightest metal with the highest potential due to its very reactive behavior, which, in
theory, makes it very fitting as a compound for batteries. Just as the lead-acid and most other
batteries the Lithium-Ion battery by definition uses chemical reactions to release electricity.

14. Lithium-Ion Batteries3.3.II
Advantages Disadvantages
Highest energy density in commercially available
batteries with huge potential
Very expensive
Provides higher voltages per cell (3.7V compared to
2.0V for lead-acid)
Complete discharge destroys the cells
Low energy loss: only about 5 percent per month
Deteriorates even if unused (Lifecycle of about 5
years)
Lithium and graphite as resources are available in
large amounts
Lithium is flammable in contact with atmospheric
moisture

15. Other Batteries in Development3.3.III
A) Redox-Flow Battery
These batteries technically are similar to conventional batteries, except that the
electrolytes (there are different forms, using one or two different fluids) can be exchanged,
meaning that if the battery is discharged the fluids are replaced with loaded ones. This
concept could, in theory, become very handy for electric cars as you could charge your
car simply by refueling just as you do now

16. Other Batteries in Development3.3.III
B) Sodium Battery
The liquid sodium sulfur battery is yet an-other type of
battery in development, but already operational in
some countries like Japan. About 250 Megawatts
(MW) of sodium battery power have been installed
there.5 Sodium batteries have the advantage of a
relatively high density with up to 240 Wh/kg, a long
life span of 10 – 15 years and high efficiency (75 – 90
percent); but, they need to be operated at high
temperatures (350° C/623° K) to get the sodium
liquid,

17. Other Batteries in Development3.3.III
C) Zinc-air Battery
Just like the lithium-air battery, the zinc-air battery uses air as a second component. Zinc-
air has been a focus in development for a while because of its safety aspects and
potential in density; but, was dropped due to the low efficiency and short life cycles. Two
independent companies claim to have solved these problems

18. Pumped Storage Hydroelectricity
The PSH requires two water reservoirs and
water is moved between these two levels
PSH is converting energy from electrical to
kinetic to gravitational potential and back to
kinetic and finally for electrical
Advantages Disadvantages
Mature technology,
capable of storing huge
amounts of energy
Requires a significant
huge water source
High overall efficiency Few potential sites
Inexpensive way to
store energy
Huge environmental
impacts
Fast response times
3.4

19. Compressed Air Energy Storage3.5
The basic idea is to use an electric
compressor to compress air to a pressure
of about 60 bars and store it in giant
underground spaces like old salt caverns,
aquifers or pore storage sites and to power
a turbine to generate electricity again when
demanded.

20. Compressed Air Energy Storage
the concept has two major problems when it comes to pressuring air:
1. compressing the air leads to a very significant amount of heat generation and subsequent power
loss if unused
2. the air will freeze the power turbine when decompressed.
Advantages Disadvantages
Capable of storing huge amounts of energy, similar to
PSH
Economical only up to a day of storage (for AA-CAES)
AA-CAES capable of efficiencies nearly as good as
PSH (around 70 percent)
Competing against other storage needs (natural gas,
hydrogen)
Fast response times Requires sealed storage caverns
Inexpensive way to store energy Not yet fully developed
3.5

21. Power To Gas
a technology that converts electrical power to a gas fuel. When using surplus power from wind
generation, the concept is sometimes called wind gas. There are currently three methods in use; all
use electricity to split water into hydrogen and oxygen by means of electrolysis
3.6
Concept of methanation for storing wind and solar energy

22. Power To Gas3.6
Energy losses during the methanation process

23. Thermal storage
a technology that stocks thermal energy by heating or cooling a storage medium so that the stored
energy can be used at a later time for heating and cooling applications and power generation.
3.7

24. Thermal storage3.7
Are used particularly in buildings and in industrial processes.
Advantages Disadvantages
Thermal energy storage offers the option to improve
output control for some energy technologies
The energy stored decreases with the time due to the
heat losses
Able to reduce the mismatch between supply and
demand
Some storage technologies are still in developing stage
Low maintenance requirements
Some technologies are expensive
Reliable and well-understood technology
For seasonal storage e.g. are needed big surfaces

25. Hydraulic Hydro Energy Storage
the idea is to cut out a large cylindrical body of rock and lift it
hydraulically using hydro pumps to force water underneath it.
The body would rise several hundred meters if completely
charged and would sink into the ground again during discharge.
3.8

26. Efficiency
Comparison of the efficiency for different technologies Source: GENI

27. Energy Losses & Cost
Flywheels SMES Lead-Acid Lithium-Ion PSH AA-/CAES Power to Gas
3-20%
Per hour
10-12%
Per day
5%
Per month
5%
Per year
0-0.5%
Per day
0-10%
Per day
0-1%
Per day
Life Cycle €/kWh
Flywheels 20 years 1,000 – 5,000 €
SMES 1,000,000 Cycles 30,000 – 200,000 €
Lead-Acid 1,000 - 2,000 Cycles 25 – 250 €
Lithium-Ion 500 – 3,000 Cycles or 5 Years 800 – 1,500 €
PSH - 100 – 500 €
AA-/CAES - 40 – 100 €
Power To Gas - Unknown
Source: Renews Spezial Strom Speichern

28. Capacity & Discharge time for ESS

29. Technology mix in storage installations, excluding pumped hydro

30. Case Studies

31. (Pumped Hydro ES)
Name of Project: Purulia, Pumped Storage Project
Location: India
• Generates 900 MW Instant Generation
• Cost Rs 2,953 Crore (Ten millions) ≈ 6.8 Billion EGP
Date of Commissioning: 2008
Duration: 4-6 Hrs.
Benefits: • Electric Energy Time Shift.
• Electric Supply Capacity.
Source: https://energystorageexchange.org/projects/1613 Power house
4.1

32. General view of the Purulia Project

33. Thermal Energy Storage
Name of Project: Andasol Solar Power Station
Location: Andalusia, Spain
• Generates 150 MW , expected generation is up to
495 GWh per year
• Uses PTC for collecting Solar Energy and tanks of
molten salt as thermal energy storage.
Date of Commissioning: 2009
Duration: 7.5 Hrs.
Benefits: • Renewable Capacity firming.
• Renewable Energy Time Shift.
Source: https://en.wikipedia.org/wiki/Andasol_Solar_Power_Station
https://www.renewableenergyworld.com/2008/11/06/andasol-1-goes-into-operation-54019/
4.2

34. Electro-Mechanical ES
Name of Project: Beacon Power
Location: Pennsylvania, United States
• 20 MW Plant and 5 Mwh of frequency response
• 200 flywheels that provides frequency regulation
services to grid operator.
Date of Commissioning: 2014
Duration: 0.25 hrs
Benefits: • Frequency Regulation
Source: https://en.wikipedia.org/wiki/List_of_energy_storage_projects
https://beaconpower.com/hazle-township-pennsylvania/
4.3

35. The Future of ESS?5

36. • Energy Storage Evolution Electrifies the Future of Renewables
• A Changing Regulatory Outlook
• Enthusiasm Grows as Prices Decline
• What Leads the Next Frontier of Energy Storage?
Source: https://www.bv.com/perspectives/energy-storage-evolution-electrifies-future-renewables

37. Electrochemical
Battery, 63.40%
Pumped Hydro, 28.60%
Ultra Capacitors,
23.60%
Thermal , 19.30%
Compressed air,
14.90%
Hydrogen , 13.70%
Flywheel, 9.90%
Synthetic natural gas,
5.60%
Liquid air, 5.00%
Don't know , 19.90%
WHAT TYPES OF STORAGE DO YOU FORESEE BEING
INSTRUMENTAL IN THE GRID OF THE FUTURE?
Source: black & Veatch

38. Sustainable Development4.3