Flywheel- Battery Hybrid for Grid Stability

Presentation to EERA Workshop, San Sebastian

22nd March 2017

Overview

• Use of Energy Storage in Smart Grids

• Introduction to Schwungrad Energie

• Demonstration Project

• Interaction with Grid and Market for System Services

• Benefits of dynamic energy storage – results of modelling

• Applications for the Hybrid flywheel-battery

Ireland’s electricity generation mix

• Renewable generation, mainly wind, has experienced significant growth • Gas remains dominant in the fuel mix

• Low price of coal keeps plants in merit despite high emissions

• Paradigm Shift • Centralised to distributed generation

• Synchronous to non-synchronous

0%

10%

20%

30%

40%

50%

60%

70%

Coal EU Fossil Gas Oil Renewables Peat Other

Fuel mix for electricity generation

2007 2008 2009 2010 2011 2012 2013 2014

Source: Adapted, Commission for Energy Regulation: Fuel Mix Disclosure

System Operation Issues

• Ireland is island with limited interconnection + high renewable generation targets => Grid experiencing issues now

• Renewable generation gives rise to two issues 1. Intermittent and/or unpredictable output

2. Lack of inertia/grid stability

• These require storage in different timeframes 1. Storage over many hours

2. Dynamic storage over, say, 20 minutes with a fast response time of a fraction of a second

Grid Stability

• Conventional plant with heavy generators and steam turbines had sufficient momentum to stabilise the grid – to ride through the bumps

• The more wind and PV running, the less heavy conventional plant there is to provide stability

• Need plant to provide system services to stabilise the grid without having to also provide energy

• Flywheels and batteries will do this, providing synthetic inertia and other system services

Schwungrad Energie

• Founded 2010 and formally established in 2013

• Team of industry experts • Generation, Maintenance, Markets, Project Management, Planning and Environment

• Identified growing demand for energy-less stabilising inertia • Variable renewable plant substituting conventional plant

• Targeting the Irish market initially and expanding to UK and Mainland Europe • Grids with high variable renewable (wind and solar) penetration

Hybrid flywheel-battery pilot

• 400kW Hybrid flywheel-battery pilot • Rhode, Co. Offaly, Ireland

• The site is equipped with the following: • 2 by Beacon Power Gen. 400 FESM flywheels

• 160 kW and 30 kWh

• 160 kW for 5 min and remainder for 10 min

• 192 by Hitachi Chemical LL-1500-WS Valve Regulated Lead Acid batteries

• LL 1500-WS = 160 kW and 576 kWh

• 160 kW for 3.5 hours

• 400kW connection to the 20kV distribution network

Rhode Pilot

Source: EirGrid

Hybrid flywheel-battery pilot

Vacuum Chamber

Composite rim

Magnetic lift system

Metallic hub

Rotating Shaft

Motor-Generator

Radial bearing Sub station

Control Room

Transformer

Battery Housing

PCS

Flywheels

Positive Plate

Container

Lid

Vent Valve

Retainer

Terminal

Pole

Negative Plate

How Flywheel Energy Storage Works

• Motor/generator spins a heavy flywheel which stores kinetic energy

• Energy taken from grid to speed up the flywheel • The flywheel is connected to the grid via a Power Control Module AC-DC-AC

• If grid suddenly needs more generation the flywheel control system will respond immediately and draw energy from the flywheel

• Flywheel slows down converting its kinetic energy into electrical energy

• Flywheel operates in a vacuum on magnetic bearings • Noise and vibration are negligible

• Flywheel isolates battery from excessive cycling, extending its lifespan

Flywheel/Battery Hybrid (System Services Application)

Battery

Kinetic Energy Storage Chemical Energy Storage

Capabilities • High Power • Restricted energy storage • Fast response • Millions of charge/

discharge cycles

Capabilities • High energy storage • Fast response • Thousands of charge/

discharge cycles

+ Flywheel

System Services • Frequency Regulation • Response << 1 sec • Fast Freq Response • POR • SOR • TOR1

System Services • Response << 1 sec • Fast Freq Response • POR • SOR • TOR1 • TOR2

System (Ancillary) Services

• Ancillary Services • Stabilise the grid frequency

• Maintain 50Hz (±0.1Hz)

• Manage Rate of Change of Frequency (RoCoF)

• New services designed to maintain stability with increased penetration of variable renewables • Fast response – additional power

injection (500ms)

• Hybrid flywheel-battery capable of providing power without energy • Avoids curtailment of renewables

• Effective and efficient source

Existing Services

SRP Steady-state reactive power

POR Primary Operating Reserve 5s – 15s

SOR Secondary Operating Reserve 15s – 90s

TOR1 Tertiary Operating Reserve 1 90s – 5min

TOR2 Tertiary Operating Reserve 2 5min – 20min

RRD Replacement Reserve (De-Synchronised) 20min – 1h

RRS Replacement Reserve (Synchronised) 20min – 1h

New Services

SIR Synchronous Inertial Response

FFR Fast Frequency Response 2s – 10s

DRR Dynamic Reactive Response

RM1 Ramping Margin 1 Hour 1h – 3h

RM3 Ramping Margin 3 Hour 3h – 9h

RM8 Ramping Margin 8 Hour 8h – 16h

FPFAPR Fast Post-Fault Active Power Recovery 250ms – 15min

49.30

49.35

49.40

49.45

49.50

49.55

49.60

49.65

49.70

49.75

49.80

49.85

49.90

49.95

50.00

50.05

50.10

50.15

50.20

50.25

Gri

d F

req

ue

ncy

(H

z)

Nominal frequency

Problem

Example of real system frequency event

± 0.10 Hz – Acceptable deviation

20/02/2014 22:38:49 49.345 Hz

Sample of frequency events - RoCoF

-1.5

-1.0

-0.5

0.0

0.5

1.0

48.5

49.0

49.5

50.0

50.5

51.0

-2 -1 0 1 2 3 4 5 6 7 8

Ro

Co

F (

Hz/

s)

Fre

qu

en

cy (

Hz)

Time (s)

Sample Low Frequency RoCoF (with quick Frequency Rise)

Frequency (Hz)

RoCoF (Hz/s)

-1.5

-1.0

-0.5

0.0

0.5

1.0

48.5

49.0

49.5

50.0

50.5

51.0

-2 -1 0 1 2 3 4 5 6 7 8

Ro

Co

F (

Hz/

s)

Fre

qu

en

cy (

Hz)

Time (s)

Sample High Frequency RoCoF (with quick Frequency Drop)

Frequency (Hz)

RoCoF (Hz/s)

-1.5

-1.0

-0.5

0.0

0.5

1.0

48.5

49.0

49.5

50.0

50.5

51.0

-2 -1 0 1 2 3 4 5 6 7 8

Ro

Co

F (

Hz/

s)

Fre

qu

en

cy (

Hz)

Time (s)

Sample Low Frequency RoCoF

Frequency (Hz)

RoCoF (Hz/s)

-1.5

-1.0

-0.5

0.0

0.5

1.0

48.5

49.0

49.5

50.0

50.5

51.0

-2 -1 0 1 2 3 4 5 6 7 8

Ro

Co

F (

Hz/

s)

Fre

qu

en

cy (

Hz)

Time (s)

Sample High Frequency RoCoF

Frequency (Hz)

RoCoF (Hz/s)

0

20

40

60

80

100

120

140

160

180

49.40

49.45

49.50

49.55

49.60

49.65

49.70

49.75

49.80

49.85

49.90

49.95

50.00

50.0510

:11:

57

10:1

2:0

6

10:1

2:1

5

10:1

2:2

4

10:1

2:3

3

10:1

2:4

2

10:1

2:5

1

10:1

3:0

0

10:1

3:0

9

10:1

3:18

10:1

3:2

7

10:1

3:36

10:1

3:4

5

10:1

3:54

10:1

4:0

3

10:1

4:1

2

10:1

4:2

1

10:1

4:3

0

10:1

4:3

9

10:1

4:4

8

10:1

4:5

7

10:1

5:0

6

10:1

5:15

10:1

5:2

4

10:1

5:33

10:1

5:4

2

10:1

5:51

10:1

6:0

0

10:1

6:0

9

10:1

6:1

8

10:1

6:2

7

10:1

6:3

6

10:1

6:4

5

10:1

6:5

4

10:1

7:0

3

10:1

7:12

10:1

7:2

1

10:1

7:30

10:1

7:39

10:1

7:4

8

10:1

7:57

10:1

8:0

6

10:1

8:1

5

10:1

8:2

4

10:1

8:3

3

10:1

8:4

2

10:1

8:5

1

10:1

9:0

0

10:1

9:0

9

10:1

9:1

8

10:1

9:2

7

PO

WE

R O

UT

PU

T (K

W)

FR

EQ

UE

NC

Y (

HZ

)

Power (kW) Frequency (Hz)

Frequency threshold for full power output

Nominal frequency

On/OFF Load Changes

11/03/2014 10:12:44 – 10:16:43 Full power for 4 minutes

Event – rapid drop in frequency

Hybrid flywheel-battery response

Frequency recovery

Frequency drop

Frequency recovery

Simulated response of Hybrid flywheel-battery (160kW) to real grid event

Response of Hybrid flywheel-battery

Actual Response to System Frequency Event

-60

-40

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

280

300

320

340

360

49.300

49.400

49.500

49.600

49.700

49.800

49.900

50.000

50.100

0 5 10 15 20 25 30

Po

wer

Ou

tpu

t (k

W)

Sys

tem

Fre

qu

en

cy (H

z)

17/07/2016 at 10:46:19.390

Frequency P:Flywheels P:Batteries

Benefits of Dynamic Energy Storage - Modelled

• Model of Irish Grid developed by University of Limerick (Robert Lynch, Nathan Quill, Catherine Leninhan)

• Effect of battery energy storage under different scenarios

• Some examples of results under a scenario of insufficient Primary Operating Reserve from conventional synchronous generators

Frequency Plot with Insufficient POR

Frequency Plot with Insufficient POR

Minimum Frequency with Insufficient POR

Maximum RoCoF with Insufficient POR

Effect of Battery Response Time

Applications for Hybrid Energy Storage

• Dedicated System Service Facility • DS3 Market in Ireland

• EFR market in Great Britain

• Similar markets in other European countries and worldwide (JV in China, visit to Vietnam in April)

• Co-Location with existing/new build Conventional or Renewable Generator • Enhance performance of conventional plant

• Improve “firmness” of renewable plant

• Co-location with renewable generation and demand (large industrial customers or microgrids)

Conclusions

• Integration of high levels of non-synchronous intermittent and unpredictable renewable generation onto the grid will require hybrid energy storage for • Load shifting, load balancing

• Grid stability

• Grid stability an issue already in Ireland and will become an issue across Europe as all countries reach high levels of non-synchronous plant

• A hybrid of flywheels and batteries has been demonstrated by Schwungrad to provide reliable rapid response to changes in system frequency

• EU policies on electricity markets, grid codes etc. must support and not hinder the roll-out of dynamic energy storage to stabilise the grids with increasing levels of renewable generation to allow the decarbonising of electricity

Thank You