1. Mechanical Energy Storage
Created by Nick Stroud
Nick � I like this topic very much. I think you could possibly choose all three, with a brief overview of each, comparison of advantages and disadvantages between them, and I think the most course-relevant part which a comparison with electrochemical storage (battery, capacitor, fuel cell). Go for it.

2. Three Types of Storage Pumped hydroelectric storage (PHS)
Compressed air energy storage (CAES)
Flywheels

3. Pumped Hydroelectric Storage (PHS)
Used for load balancing of energy
Water is pumped up in elevation during time of low demand
Water flows back down during times of high demand
Turbines recapture the energy.

4. Pumped Hydroelectric Storage (PHS)
70-85% of electrical energy is recovered
Energy loss due to evaporation and Pump/generator inefficiency
Currently the most cost effective way to store large amounts of electricity
Low energy density calls for large bodies of water
Never used in portable technology
1000 kg at 100 ft = .272 kWh

5. Pumps: On the Grid The Us has 19.5 gigawatts capacity 2.5% of baseload
Technology is in use world wide
Hundreds of plants around the world
Man made reservoirs as well as natural reservoirs

6. Future Of PHS
This energy storage can be used to level the grid for renewable energy
Wind power and solar power are not constantly on
Using salt mines to increase energy density

7. Compressed air energy storage (CAES)
Large tank is buried underground
During times of low demand electricity compresses air
During times of peak demand compressed air is heated and released

8. Types Of CAES Adiabatic storage Diabatic storage
Heat from compression is captured and stored in a solid or liquid
Hot Oil 3000C
Molten Salt 6000C
Heat is reincorporated during release
Close to 100% efficiency
No utility scale plants
Diabatic storage
Heat is lost through cooling
Natural gas is burned to reheat compressed air
Very inefficient 38-68%
Uses 1/2 gas of an all gas plant

9. More about CAES Can use sandstone layer to hold compressed air
USA has good ground for this type of storage
Can be used to level load from wind and solar
MW Plants

10. Compressed air in Cars Zero pollution Motors
Stores air at around 300atm
Under 35 mph it is zero emissions
Over 35 mph uses combustion engine to compress air
Runs on many different types of fuel
1 air tank + 8 gal gas= 848 miles

11. Fueling/Refueling
Flex engine runs off of gas, diesel, alcohol, possibly even vegetable oil
Refueling air tank at refuel station about 3 minutes
Home refuel unit takes 4 hours, electrical cost $2
3 cents per mile

12. FlowAir After 35 mph only 1/2 the CO2 emissions of Prius
Takes advantage of light engine and light frame to be efficient
Uses fiberglass frame filled with foam
May lose efficiency in cold weather

13. Future of Air Vehicles Flowair- release in 2010
First needs to pass US safety ratings
6 seats
106 mpg
mile range
Top speed 96 mph
$17500

14. Flywheels Captures energy in a rotating Mass
Flywheel is charged using electric motor
Electric generator extracts energy

15. Operation Of Flywheel
Energy held in Spinning Rotor (Steel or Carbon composite)
Steel rotors can spin at several thousand rpm
Carbon composite spin up to 60k rpm
Kinetic Energy 1/2mv2

16. Bearings Mechanical bearings not practical
Friction is directly proportional to speed
Magnetic bearings used to minimize friction
Rotor is suspended- state of levitation
Operates in a Vacuum

17. Superconductors
New technology uses high temperature superconductors (HTSC)
HTSC operate at -1960C or -3210F
Diamagnetism- creates a field of opposition to a magnetic field
Hybrid systems use conventional magnets to levitate and superconductors to stabilize

19. Flywheels Vs. Batteries
Pros
Cons
Not effected by temperature changes
No Memory Effect
Made more environmentally friendly
Easy energy content identification
Shattering due to overload
Safety devices add lots of mass
Gyroscope (duel FES systems)

20. Energy Stats Composite Flywheel Li-ion Battery Cycles
100,000 to 10 million
Around 1200
Energy Density
130 Wh/kg
160 Wh/kg
Capacity
Range from 3 kWh to Max of 133 KWh
Equal to 13, Li-ion
Over 4 times what is used to power the Tesla
Charge Time
15 min
Several Hours
Self discharge time
“0 run down time”- Years
10-20 months
Energy Exchange
Limited by generator
Limited by chemical process

21. Flywheels have High
volumetric density

22. Flywheel Projects Gyrobuses- used in 1950s in Switzerland
Buses run off of Flywheels
Never gained economic foothold
Low fuel costs compared to electricity

23. Flywheel Projects
Flywheels used in electric trains to carry over gaps and regenerative breaking
Some car models tried (Rosen Motors)
Formula 1 competition
Used on systems that need Uninterrupted power supply. (maintenance 1/2 cost of battery)
Testing of fuses

24. Sources http://zeropollutionmotors.us/