battery storage in the nem (subbing for nilesh modi... · grid scale energy storage 2 applications...

Battery Storage in the NEMDr Nilesh Modi

Australia Energy Market Operator

Grid scale energy storage

2

Applications

Frequency Control

SpecialProtectionScheme

Inertia substitution

Reliability

SA

VIC

NSW

Hornsdale Power Reserve (Tesla Battery)

3

March 2017

Energy Arbitrage

System Security

Nov 2017

70 MW / 10 MWh

30 M W / 119

MWh

• Change in set point through AGC

• Large steam turbine : Complex dynamic system, inner and outer control systems, lead lag controllers

• Battery Energy Storage: Relatively simple dynamics

Frequency Control - Regulation

4

Battery

Battery

Frequency Control - Contingency

• Faster sustained responses are generally achieved with inverter connected generation, due to

avoidance or decoupling of mechanical components

• Change in the direction of flow (generation to load)

5

50 Hz to 49.5 Hz at 0.5 Hz/s

Frequency Control – Island mode

• Frequency control in an island

• Size of the battery relative to the demand

6Data provided by ElectraNet

System Integrity Protection Scheme7

• Detect unstable power swings between South

Australia and Victoria

Stage 1 Stage 2 Stage 3~800 km

(~500 miles)

Heywood AC I/C

EnergyDischarge

Pre-emptive

Load Shedding

Separation

System Integrity Protection Scheme

• Effectiveness of BESS on overall system security

• System separation avoided

• Increased effectiveness of load shedding

8

System inertia

• Factors to consider

• Availability and capability of PrimaryFrequency Response (PFR) / FrequencyContainment Reserve (FCR)

• Maximum contingency size

• Possible further loss of inertia

• Maximum RoCoF

9

Inertia substitution

• FFR is more effective for low inertia systems compared to high inertia systems

• As an example, for a contingency size of 300 MW, dispatching 20% FFR from total FCR,

• 6.5% reduction in the inertia requirements for a system with 20,000 MWs total inertia

• 17% reduction in the inertia requirements for a system with 15,000 MWs inertia, respectively

10

Relationship between FFR and Inertia Relationship between FFR and RoCoF

Reference: Inertia requirements methodology, inertia requirements & shortfalls, AEMO 2018

Questions?