Energy Limit in BDU Bids

Energy The unit must be a generator for the service type: ‘energy’. Loads cannot bid for mandatory restrictions capacity. limits in BDU Bi-directional Unit. A bi-directional unit capable of charge and discharge; for example, battery technologies. bids are are optional provision and used only in pre-dispatch and 7-day pre-dispatch. The Energy Limit field represents the Storage Capacity PASA Availability, as described in clause 3.7.2(d)(1) of the National Electricity Rules and the NER glossary. Limit (in MWh) applied for an interval. For the bid GEN direction, this is the minimum Storage Capacity Limit and for bid LOAD direction, it is the maximum Storage Capacity Limit. AEMO Australian Energy Market Operator’s Dispatch See National Electricity Rules systems create constraints to limit the MW Megawatt dispatch so the Energy (MWh) in storage at the end of an interval remains within the minimum and maximum Storage Capacity Limit values.

Bid See Relevant Rules or Procedures Energy Limit only limits Energy MW targets. Regulation and Contingency FCAS Frequency Controlled Ancillary Services. A service that balances, over short intervals (shorter than the dispatch interval), the power supplied by generating units and the power consumed by loads. targets are not affected by the bid energy limits.

The system rejects an Energy bids if:

• The bid Energy Limit (either GEN or LOAD direction)is greater than the registered maximum storage capacity.
• The minimum energy limit (GEN direction) is less than zero, or,
• The minimum energy limit (GEN direction) is greater than the maximum energy limit.

Participants can decide how the BDU DUID Dispatchable Unit Identifier Storage Capacity constraints are applied.

• For the intervals where participants provide Energy Limits in Bid for both the GEN and LOAD directions, the Dispatch systems create constraints to limit the dispatch target (MW) so the Energy (MWh) in the storage at the end of the interval remains within the minimum and maximum Storage Capacity respectively.
• For the intervals where participants do not provide the Energy Limits in bid:
  • If there is no bid Energy Limit for the GEN direction and the participant has opted in to apply the Operational State of Charge constraints during registration, the Dispatch system creates a minimum Storage Capacity based on the registered Minimum Operational State of Charge value. If the participant has not opted in to apply Operational State Of Charge constraints during registration, then no minimum Storage Capacity constraint is created.
  • If there is no bid Energy Limit for the LOAD direction and the participant has opted in to apply the Operational State of Charge constraints during registration, the Dispatch system creates a maximum Storage Capacity constraint based on the registered Maximum Operational State Of Charge value. If the participant has not opted in to apply Operational State Of Charge constraints during registration, then no maximum Storage Capacity constraint is created.

  Fields in Registration	Units	Definition	Use in AEMO's Dispatch Systems
  Apply operational state of charge constraint (Op SOC State of Charge, energy availability of batteries (in MWh) Constraint See Relevant Rules or Procedures)?	Yes or No	If Yes, apply the Minimum and Maximum Operational SOC constraints if Energy Limits are not provided in bids.	Triggers use of the min and max Operational SOC as defaults in AEMO’s Predispatch and 7-day Predispatch.
  Min Operational State of Charge	MWh	The minimum operational state of charge (MWh)	Applied if Op SOC Constraint is Yes. Overwritten if min EnergyLimit is provided in bids.
  Max Operational State of Charge	MWh	The maximum operational state of charge (MWh)	To be applied if Op SOC Constraint is Yes. Overwritten if max EnergyLimit is provided in bids

Participants can use the Operational SOC as default values and overwrite them by providing the energy limits in bids if/when needed.

Fields in Bids	Units	Definition	Use in AEMO's Dispatch Systems
Min EnergyLimit (EnergyLimit in GEN direction)	MWh	The minimum state of charge (MWh)	Limits will be applied in AEMO’s Predispatchand 7-day Predispatch.
Max EnergyLimit (EnergyLimit in LOAD direction)	MWh	The maximum state of charge (MWh)	Limits will be applied in AEMO’s Predispatch and 7-day Predispatch.