Superconducting High-speed Flywheel Energy Storage Systems C. Boffo - Babcock Noell GmbH Page 1
Takeaways
Energy storage is a necessary foundation of our electricity grid High speed flywheels are a workhorse for highly cyclic applications Superconductivity is key to enable flywheels to over perform other technologies
Babcock Noell GmbH – Cristian Boffo
ESAS Summer School 2016 – Bologna
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Content About FW The physics of flywheels Energy storage Applications Evolution of the flywheel Enter superconductivity FW design Parameter space Components design Safety of the flywheel Source: Bilfinger Construction GmbH
Babcock Noell GmbH – Cristian Boffo
ESAS Summer School 2016 – Bologna
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ABOUT FLYWHEELS
Babcock Noell GmbH – Cristian Boffo
ESAS Summer School 2016 – Bologna
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The flywheel What?
A flywheel is a rotating mechanical device that can store kinetic energy to:
provide continuous energy when the source is discontinuous
deliver energy at rates above the one provided by the continuous source
Babcock Noell GmbH – Cristian Boffo
ESAS Summer School 2016 – Bologna
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The physics
All about ONE equation
1 = 2 Where: E is the stored kinetic energy (Joules) I is the moment of inertia of the rotating mass (kg/m2) ω is the angular velocity (rad/s) Babcock Noell GmbH – Cristian Boffo
ESAS Summer School 2016 – Bologna
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Flywheel
When was the flywheel invented?
The principle of the flywheel is founded on the Neolithic spindle and on the potter´s wheel.
6500 B.C.
Babcock Noell GmbH – Cristian Boffo
ESAS Summer School 2016 – Bologna
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The quest for energy storage Why is it important?
Short answer: storing energy is economically very lucrative! In a time when the renewable energy share is growing, energy storage is a key building block for a stable network Production and distribution of electricity have been technologically solved, but there is still no standard solution for energy storage in the grid A number of stand-alone applications can benefit Source: Eurostat
from energy storage to improve efficiency Babcock Noell GmbH – Cristian Boffo
ESAS Summer School 2016 – Bologna
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The quest for energy storage Grid example
Isolated networks: Sicily – island High renewables share that most of the time cannot be fully absorbed by users Need of traditional power plants to cope with peaks and low sun/wind days Solution: Expensive 1100 MW submarine cable requiring 12 years to be operative (700 MEuro) Alternative Solution: Energy storage system that can compensate for the fluctuations. How much storage capacity could one install for the same investment? 350 MW when using the top commercial battery technology!
Babcock Noell GmbH – Cristian Boffo
Source: Il Sole 24 Ore
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ESAS Summer School 2016 – Bologna
The quest for energy storage Available technologies
Energy storage systems
Electrical
Mechanical
Thermal
Chemical
Super cap SMES
Pump hydro Compressed air Flywheel
Thermoelectric
Batteries Hydrogen Natural gas
Short
Medium
Long
Time scale Babcock Noell GmbH – Cristian Boffo
ESAS Summer School 2016 – Bologna
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The quest for energy storage Comparison between technologies
Flywheel: a power storage device Fast absorption and release of energy (10 ms deployment time) Short term storage (minutes) Low energies (50 Wh/kg)
Source: TU Braunschweig, Prof. Canders
Babcock Noell GmbH – Cristian Boffo
ESAS Summer School 2016 – Bologna
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Unique FW features SWOT Analysis
Babcock Noell GmbH – Cristian Boffo
Strengths: Fast charging Long lifetime Low maintenance
Weaknesses: Low energy density Vacuum required For SC Cryogenics
Opportunities: Also used as frequency control
Threats: There are cheaper technologies
ESAS Summer School 2016 – Bologna
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Flywheel Where?
APPLICATIONS OF FLYWHEELS
Babcock Noell GmbH – Cristian Boffo
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ESAS Summer School 2016 – Bologna
Typical FW applications Cranes
Highly cyclic applications such as a crane:
Example: Container payload
30 tons
Store energy when moving the load down
Hoist distance
10 m
Use stored energy when moving load up
Required energy
3 MJ
Limited amount of time ( 1,4
Cylindrical rotor
Jp/Je < 0,7
Babcock Noell GmbH – Cristian Boffo
Jp
Je
ESAS Summer School 2016 – Bologna
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Basic integrated design of a FW Examples
Crane FW Energy
Mobility FW
0.45 kWh
Energy
2.5 kWh
SC FW Energy
4.0 kWh
Rotating speed 8000 rpm
Rotating speed 6000 rpm
Rotating speed 16000 rpm
Tip speed ~750 km/h
Tip speed ~550 km/h
Tip speed >2000 km/h
Diameter 0.5 m
Diameter 0.5 m
Diameter 0.7 m
Height
0.1 m
Height
1m
Height
0.2 m
Mass
150 kg
Mass
1500 kg
Mass
120 kg
Hoop stress 342 MPa
Hoop stress 192 MPa
Hoop stress 550 MPa
Jp/Je
Jp/Je
Jp/Je
~1.9
Babcock Noell GmbH – Cristian Boffo
~0.32
ESAS Summer School 2016 – Bologna
~1.8
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Flywheel How?
COMPONENT DESIGN
Babcock Noell GmbH – Cristian Boffo
ESAS Summer School 2016 – Bologna
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Flywheel How?
safety
auxiliaries
SC bearing
FW
motor and electronic
Babcock Noell GmbH – Cristian Boffo
cryogenics
rotor dynamics
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ESAS Summer School 2016 – Bologna
Flywheel How?
SUPERCONDUCTING BEARINGS SC bearing
safety
auxiliaries
FW
cryogenics
motor and rotor electronic dynamics
Babcock Noell GmbH – Cristian Boffo
ESAS Summer School 2016 – Bologna
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Superconducting bearing design Principle
The simplest case of SC bearings is the levitation of a permanent magnet over a superconductor using the “operational field cooling with offset” method.
