National Electricity Market (NEM)

Australia: Australian Capital Territory, New South Wales, Queensland, South Australia, Tasmania and Victoria. Status: operational.

Wholesale design: Mandatory gross-pool, security-constrained dispatch. Energy and ten FCAS products are co-optimised in five-minute dispatch intervals; energy is regionally priced and FCAS has regional prices and requirements.

Operator
Australian Energy Market Operator (AEMO)
Nominal frequency
50 Hz
Where energy trades

Where does energy trade in National Electricity Market (NEM)?

Energy in National Electricity Market (NEM) trades in 2 layers: five-minute spot energy and financial contracts outside the pool.

What a battery can sell

What ancillary services can a battery sell in National Electricity Market (NEM)?

National Electricity Market (NEM) has 10 ancillary-service products, across 3 families — regulation, fast frequency response and other services: Delayed Lower FCAS, Delayed Raise FCAS, Fast Lower FCAS, Fast Raise FCAS, Regulating Lower Service, Regulating Raise Service, Slow Lower FCAS, Slow Raise FCAS, and 2 more. Response timing, direction and eligibility for each are in the table below; a product's full record lists the official sources behind it.

Every value below comes from the official sources listed in that product's full record. Most products cite more than one, and the published sources do not say which of them states each individual value, so the binding is to the product's record rather than to a single document. A missing line means the source does not state that value — never that the value is zero.

Scroll the table sideways for the rest of the columns →

10 ancillary-service products in National Electricity Market (NEM), grouped into 3 families. Each row runs left to right through one product's life: how it activates, how quickly it has to respond, how long it has to keep delivering, and how it is bought.
Service How it activates Response Sustained delivery Procurement
Regulation
Regulating Lower Service LREG lower generation; raise load operational Response type pre-fault centrally controlled AGC Trigger AEMO AGC Lower Signals; not a fixed public frequency threshold. Full activation 5 min As stated Requirements vary by interval and region; no stable official typical range is prescribed. Requirements vary by interval and region; no stable official typical range is prescribed. Through security-constrained co-optimised FCAS spot market Bought daily bids with five-minute dispatch and rebidding How it settles Five-minute regional FCAS clearing price for enabled MW, with frequency-performance-payment arrangements under the current settlement guide.
Full record for Regulating Lower Service — document bound, page for these figures not recorded
What it is for

Support control of system frequency and accumulated time error for ordinary supply-demand variations within a trading interval.

In force from

3 June 2024

Who can provide it

AEMO-registered and enabled FCAS facilities meeting MASS, telemetry, control and minimum-offer requirements.

Notes from the source

MASS defines the offered quantity as response delivered progressively over the five-minute trading interval; AGC requests may change during that interval, so there is no separate fixed hold duration.

Checkpoint recap

Full activation 5 min

What the source does not state

The source states the full-activation requirement and a procurement volume in its own words. It does not state how long delivery has to be sustained.

Regulating Raise Service RREG raise generation; lower load operational Response type pre-fault centrally controlled AGC Trigger AEMO AGC Raise Signals; not a fixed public frequency threshold. Full activation 5 min As stated Requirements vary by interval and region; no stable official typical range is prescribed. Requirements vary by interval and region; no stable official typical range is prescribed. Through security-constrained co-optimised FCAS spot market Bought daily bids with five-minute dispatch and rebidding How it settles Five-minute regional FCAS clearing price for enabled MW, with frequency-performance-payment arrangements under the current settlement guide.
Full record for Regulating Raise Service — document bound, page for these figures not recorded
What it is for

Support control of system frequency and accumulated time error for ordinary supply-demand variations within a trading interval.

In force from

3 June 2024

Who can provide it

AEMO-registered and enabled FCAS facilities meeting MASS, telemetry, control and minimum-offer requirements.

Notes from the source

MASS defines the offered quantity as response delivered progressively over the five-minute trading interval; AGC requests may change during that interval, so this is not a step-response guarantee and there is no separate fixed hold duration.

Checkpoint recap

Full activation 5 min

What the source does not state

The source states the full-activation requirement and a procurement volume in its own words. It does not state how long delivery has to be sustained.

Fast frequency response
Very Fast Lower FCAS L1 lower generation; raise load operational Response type post-fault automatic local frequency Trigger Enabled resource responds automatically when local frequency moves outside the normal operating frequency band; the MASS uses a verification ramp rather than one universal relay setting. Full activation 1 s As stated Dynamic constraint requirements; no stable typical range. Dynamic constraint requirements; no stable typical range. Through co-optimised contingency FCAS spot market Bought daily bids with five-minute enablement and rebidding How it settles Five-minute regional enablement price; delivery is verified under MASS.
Full record for Very Fast Lower FCAS — document bound, page for these figures not recorded
What it is for

Arrest an over-frequency excursion in the first second after a contingency and transition to Fast Lower FCAS.

In force from

3 June 2024

Who can provide it

Registered FCAS facilities capable of automatic local-frequency response and MASS-compliant high-speed metering.

Notes from the source

Offer measurement uses response from disturbance time to 1 s and transition from 1 s to 6 s; no independent fixed hold duration is specified.

Checkpoint recap

Full activation 1 s

What the source does not state

The source states the full-activation requirement and a procurement volume in its own words. It does not state how long delivery has to be sustained.

Sources
Very Fast Raise FCAS R1 raise generation; lower load operational Response type post-fault automatic local frequency Trigger Enabled resource responds automatically when local frequency moves outside the normal operating frequency band; the MASS verifies against the applicable frequency ramp, not one universal relay setting. Full activation 1 s Reported, not a current requirement Dynamic constraint requirements; transition caps have changed over time and are not a typical volume. Dynamic constraint requirements; transition caps have changed over time and are not a typical volume. Through co-optimised contingency FCAS spot market Bought daily bids with five-minute enablement and rebidding How it settles Five-minute regional enablement price; delivery is verified under MASS.
Full record for Very Fast Raise FCAS — document bound, page for these figures not recorded
What it is for

Arrest an under-frequency excursion in the first second after a contingency and transition to Fast Raise FCAS.

In force from

3 June 2024

Who can provide it

Registered FCAS facilities capable of automatic local-frequency response and MASS-compliant high-speed metering.

Notes from the source

Offer measurement uses response from disturbance time to 1 s and transition from 1 s to 6 s; no independent fixed hold duration is specified.

Checkpoint recap

Full activation 1 s

What the source does not state

The source states the full-activation requirement and a procurement volume in its own words. It does not state how long delivery has to be sustained.

Sources
Other services
Delayed Lower FCAS L5 lower generation; raise load operational Response type post-fault automatic local frequency Trigger Automatic local-frequency response after a contingency. Full activation 5 min Minimum obligation at least 5 min As stated Dynamic constraint requirements. Dynamic constraint requirements. Through co-optimised contingency FCAS spot market Bought daily bids with five-minute enablement and rebidding How it settles Five-minute regional enablement price; delivery verified under MASS.
Full record for Delayed Lower FCAS — document bound, page for these figures not recorded
What it is for

Return frequency toward 50 Hz within five minutes and sustain response until central dispatch can rebalance the system.

In force from

3 June 2024

Who can provide it

Registered MASS-compliant generation, storage or responsive load.

Notes from the source

MASS offer calculation measures the delivered response over 1-5 min and again over 5-10 min; 300 s is the verification sustain window after full response.

Checkpoint recap

Full activation 5 min · Minimum sustained 5 min

What the source does not state

The source states the full-activation requirement, a minimum delivery period, and a procurement volume in its own words. It does not state a maximum duration.

Sources
Delayed Raise FCAS R5 raise generation; lower load operational Response type post-fault automatic local frequency Trigger Automatic local-frequency response after a contingency. Full activation 5 min Minimum obligation at least 5 min As stated Dynamic constraint requirements. Dynamic constraint requirements. Through co-optimised contingency FCAS spot market Bought daily bids with five-minute enablement and rebidding How it settles Five-minute regional enablement price; delivery verified under MASS.
Full record for Delayed Raise FCAS — document bound, page for these figures not recorded
What it is for

Return frequency toward 50 Hz within five minutes and sustain response until central dispatch can rebalance the system.

In force from

3 June 2024

Who can provide it

Registered MASS-compliant generation, storage or responsive load.

Notes from the source

MASS offer calculation measures the delivered response over 1-5 min and again over 5-10 min; 300 s is the verification sustain window after full response.

Checkpoint recap

Full activation 5 min · Minimum sustained 5 min

What the source does not state

The source states the full-activation requirement, a minimum delivery period, and a procurement volume in its own words. It does not state a maximum duration.

Sources
Fast Lower FCAS L6 lower generation; raise load operational Response type post-fault automatic local frequency Trigger Automatic local-frequency response after a contingency; provider-specific droop or switching settings apply. Full activation 6 s As stated Dynamic constraint requirements. Dynamic constraint requirements. Through co-optimised contingency FCAS spot market Bought daily bids with five-minute enablement and rebidding How it settles Five-minute regional enablement price; delivery verified under MASS.
Full record for Fast Lower FCAS — document bound, page for these figures not recorded
What it is for

Arrest an over-frequency excursion within six seconds and transition to Slow Lower FCAS.

In force from

3 June 2024

Who can provide it

Registered MASS-compliant generation, storage, responsive load or aggregated facilities.

Notes from the source

Measured over 1-6 s and 6-60 s transition windows; no separate fixed hold duration.

Checkpoint recap

Full activation 6 s

What the source does not state

The source states the full-activation requirement and a procurement volume in its own words. It does not state how long delivery has to be sustained.

Sources
Fast Raise FCAS R6 raise generation; lower load operational Response type post-fault automatic local frequency Trigger Automatic local-frequency response after a contingency; provider-specific droop or switching settings apply. Full activation 6 s As stated Dynamic constraint requirements. Dynamic constraint requirements. Through co-optimised contingency FCAS spot market Bought daily bids with five-minute enablement and rebidding How it settles Five-minute regional enablement price; delivery verified under MASS.
Full record for Fast Raise FCAS — document bound, page for these figures not recorded
What it is for

Arrest an under-frequency excursion within six seconds and transition to Slow Raise FCAS.

In force from

3 June 2024

Who can provide it

Registered MASS-compliant generation, storage, responsive load or aggregated facilities.

Notes from the source

Measured over 1-6 s and 6-60 s transition windows; no separate fixed hold duration.

Checkpoint recap

Full activation 6 s

What the source does not state

The source states the full-activation requirement and a procurement volume in its own words. It does not state how long delivery has to be sustained.

Sources
Slow Lower FCAS L60 lower generation; raise load operational Response type post-fault automatic local frequency Trigger Automatic local-frequency response after a contingency. Full activation 60 s As stated Dynamic constraint requirements. Dynamic constraint requirements. Through co-optimised contingency FCAS spot market Bought daily bids with five-minute enablement and rebidding How it settles Five-minute regional enablement price; delivery verified under MASS.
Full record for Slow Lower FCAS — document bound, page for these figures not recorded
What it is for

Stabilise over-frequency within 60 seconds and transition to Delayed Lower FCAS.

In force from

3 June 2024

Who can provide it

Registered MASS-compliant generation, storage or responsive load.

Notes from the source

Measured over 6-60 s and 60 s-5 min transition windows; no separate fixed hold duration.

Checkpoint recap

Full activation 60 s

What the source does not state

The source states the full-activation requirement and a procurement volume in its own words. It does not state how long delivery has to be sustained.

Sources
Slow Raise FCAS R60 raise generation; lower load operational Response type post-fault automatic local frequency Trigger Automatic local-frequency response after a contingency. Full activation 60 s As stated Dynamic constraint requirements. Dynamic constraint requirements. Through co-optimised contingency FCAS spot market Bought daily bids with five-minute enablement and rebidding How it settles Five-minute regional enablement price; delivery verified under MASS.
Full record for Slow Raise FCAS — document bound, page for these figures not recorded
What it is for

Stabilise under-frequency within 60 seconds and transition to Delayed Raise FCAS.

In force from

3 June 2024

Who can provide it

Registered MASS-compliant generation, storage or responsive load.

Notes from the source

Measured over 6-60 s and 60 s-5 min transition windows; no separate fixed hold duration.

Checkpoint recap

Full activation 60 s

What the source does not state

The source states the full-activation requirement and a procurement volume in its own words. It does not state how long delivery has to be sustained.

Sources
Getting paid to exist

Does National Electricity Market (NEM) have a capacity mechanism?

No central capacity market. National Electricity Market (NEM) has 1 capacity/adequacy arrangement — Retailer Reliability Obligation and Reliability and Emergency Reserve Trader — and it works differently.

Retailer Reliability Obligation and Reliability and Emergency Reserve Trader

operational

If a material forecast reliability gap is identified, the RRO can require liable retailers and large users to demonstrate qualifying contracts for their share of peak demand. AEMO can separately contract out-of-market reserves through RERT.

Auction held in 2025
No — No capacity auction for this market was found to have been held during 2025 in the sources reviewed.

There was no NEM-wide capacity-market auction in calendar 2025. RRO contracting and RERT reserve contracting is not a central capacity auction.

Caveats

Technical notes

Two regulation FCAS markets and eight contingency FCAS markets; non-market system restart and network support services are contracted separately.

Where this comes from

Official sources

Capacity-mechanism explainer

Current as of · from the Global Electricity Market Catalogue v1.2.0 (compiled to , CC BY 4.0, rendered here with wording edited for readability). Facts belong to the linked official authorities; verify the current rules before design or bidding decisions.

Questions

Common questions about National Electricity Market (NEM)

Who operates National Electricity Market (NEM)?
Australian Energy Market Operator (AEMO) operates National Electricity Market (NEM), covering Australia: Australian Capital Territory, New South Wales, Queensland, South Australia, Tasmania and Victoria.
Was a qualifying capacity event held in National Electricity Market (NEM) in 2025?
No. Retailer Reliability Obligation and Reliability and Emergency Reserve Trader: no qualifying 2025 event is recorded. No capacity auction for this market was found to have been held during 2025 in the sources reviewed.
How is energy traded, priced and settled in National Electricity Market (NEM)?
National Electricity Market (NEM): Mandatory gross-pool, security-constrained dispatch. Energy and ten FCAS products are co-optimised in five-minute dispatch intervals; energy is regionally priced and FCAS has regional prices and requirements.
Keep exploring

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