Energy Storage Overview
Thomas Johnson
Alaska Center for Energy and Power
ACEP
Alaska Center for Energy and Power
http://www.uaf.edu/acep/
(907) 474 1145
(907)
474 1143
www.uaf.edu/acep
Overview
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Why?
Types of storage
ACEP flow battery experiences
Energy storage in Alaska
Why Storage and Why Now?
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Balance supply and demand
Load leveling
Load shifting
UPS – Uninterruptible Power Supply
Potential to save fuel and $$$
Types of Storage
• Potential
– Elevation difference
– Electrochemical
– Super capacitors
– Chemical
– Magnetic
– Mechanical
• Kinetic
• Thermal
Fossil Fuel & Biomass
Hydrogen
• Yes, hydrogen can be
used for energy
storage
• In most applications
there are better
alternatives
Compressed Gas
Hydroelectric
• Reservoir storage
• Energy = mgh
• Pumped hydroelectric
~70% efficient
Needs the right circumstances
Elevation change
Super Capacitors
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“Battery”-like characteristics
Extremely rapid charge and discharge
Virtually no degradation
High self-discharge rate
Not suitable for long term storage
Flywheels
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Kinetic energy storage
Energy=1/2 mv2
Changed from heavy rotors to fast rotors
Turn around efficiency up to 85%
Short-term storage
Containment?
Batteries
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Electrochemical storage
Can be efficient
The technology is rapidly improving
Most types degrade
Other
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Liquid metal battery
Magnetic storage
Thermal storage
And…
Flow Batteries at ACEP
Flow Batteries at ACEP
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Vanadium redox batteries
VRB and Prudent Energy
Turn around efficiency 65%-75%
Very low degradation
High self-discharge rate
The “stack” was reliable
The VRB balance of plant was not
Pumps
Leaks
Storage in Alaska
• Installations throughout the state
• Various levels of success
• Or lack thereof…
• A few examples:
Usibelli Coal Mine
• Electrically-operated dragline
• 6 MW draw, 2 MW regeneration, 60
second cycle time
• Caused grid stability problems
• 40 ton, 1000 rpm Flywheel was installed
and reduced the fluctuations from 8MW
to .5 MW
• Installed in 1982 and still in use
Chena Hot Springs Batteries
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1 MW
Battery module intended as a UPS
Lead acid chemistry
Not suitable for load leveling
Never commissioned…
Premium Power Battery
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500 kW, 3.4 MWhr
Delivered to Kotzebue in October 2011
Zinc-Bromide chemistry
Intended to provide storage during times of
excess wind.
• Never commissioned
• Being returned to the manufacturer…
Wales
• Wind-diesel hybrid system
• Battery and thermal storage
enabled diesel-off operation
• System proved it could work
• For a variety of reasons, the system
is no longer used and Wales is once
again 100% diesel
Golden Valley BESS
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Largest battery in the world
Nickel-Cadmium chemistry
27 MW
6.25 MWh capacity
Electrical Energy equivalent to ~400
gallons of fuel
• It works
Questions?
For more information on the
Alaska Center for Energy and Power,
please visit
http://www.uaf.edu/acep/
Or call (907) 474-1145
Alaska Center for Energy and Power
http://www.uaf.edu/acep/ (907) 474-1145