FCAS & Ancillary Services

Overview

Frequency Control Ancillary Services (FCAS) are procured by AEMO to maintain the NEM’s 50 Hz frequency standard. The NEM procures eight distinct FCAS services in a co-optimised dispatch process alongside energy. FCAS prices can be extremely high during contingency events, making FCAS markets a critical revenue stream for flexible assets like batteries, hydro, and gas peakers.

The 8 FCAS Services

Service	Abbreviation	Response Time	Purpose
Regulation Raise	RAISEREG	Continuous	Frequency deviation above 50 Hz
Regulation Lower	LOWERREG	Continuous	Frequency deviation below 50 Hz
1-Second Contingency Raise	RAISE1SEC	1 second	Major contingency recovery
1-Second Contingency Lower	LOWER1SEC	1 second	Major contingency recovery
6-Second Contingency Raise	RAISE6SEC	6 seconds	Contingency stabilisation
6-Second Contingency Lower	LOWER6SEC	6 seconds	Contingency stabilisation
60-Second Contingency Raise	RAISE60SEC	60 seconds	Contingency arrest
60-Second Contingency Lower	LOWER60SEC	60 seconds	Contingency arrest

Note

AEMO introduced the 1-second FCAS services (RAISE1SEC and LOWER1SEC) in October 2023 to improve frequency resilience as the NEM’s renewable penetration increases and synchronous inertia declines.

FCAS Price Dynamics

FCAS prices are co-optimised with energy in AEMO’s central dispatch algorithm (NEMDE). This means:

1. Offering energy at a high price can free up a generator to provide FCAS instead
2. A binding FCAS constraint can raise energy prices significantly
3. During contingency events, FCAS prices can spike to the Market Price Cap ($16,600/MWh for energy) or even higher for FCAS (no separate cap per service)

Typical Price Ranges

Service	Normal	Elevated	Spike
RAISEREG	$5–50/MW/h	$50–500	>$500
LOWERREG	$2–30/MW/h	$30–200	>$200
RAISE6SEC	$0.10–5/MW/h	$5–100	>$1,000
LOWER6SEC	$0.05–2/MW/h	$2–50	>$500
RAISE1SEC	$0.50–10/MW/h	$10–500	>$5,000

Dashboard Pages

FCAS Price Dashboard (/front-office/fcas-prices)

• Live FCAS prices for all 8 services
• 24-hour price history chart — stacked bar showing price contribution by service
• FCAS price vs energy price correlation chart
• Enablement quantities by technology type (battery, hydro, gas, VPP)

FCAS Market Depth (/front-office/fcas-market-depth)

• Total procurement quantities for each FCAS service (MW enabled)
• Technology breakdown of FCAS providers
• Trapezium constraints showing effective FCAS capability under dispatch conditions

Contingency Event History (/front-office/fcas-contingency)

• Log of all contingency events (frequency deviations >±0.25 Hz)
• Event duration, maximum frequency deviation, response time
• FCAS price spike correlation with each event
• Post-contingency analysis: which assets responded and how quickly

FCAS Enablement

A generator or battery is enabled for FCAS when NEMDE co-optimises it to provide that service. Enablement:

• Must comply with the trapezium bid structure
• Is limited by FCAS availability offers
• Changes every 5-minute dispatch interval

-- Query FCAS enablement for batteries in last hour
SELECT
    duid,
    interval_datetime,
    raise6sec_enablement_mw,
    lower6sec_enablement_mw,
    raisereg_enablement_mw,
    lowerreg_enablement_mw,
    raise1sec_enablement_mw,
    lower1sec_enablement_mw
FROM energy_copilot.gold.nem_fcas_enablement
WHERE fuel_type = 'Battery'
  AND interval_datetime >= CURRENT_TIMESTAMP() - INTERVAL '1 HOUR'
ORDER BY interval_datetime DESC;

API Examples

Fetch Current FCAS Prices

GET /api/fcas/latest

# Response
{
  "timestamp": "2025-03-21T05:30:00Z",
  "prices": {
    "RAISEREG":  {"price": 32.50, "enablement_mw": 890},
    "LOWERREG":  {"price": 18.20, "enablement_mw": 890},
    "RAISE1SEC": {"price": 5.80,  "enablement_mw": 420},
    "LOWER1SEC": {"price": 2.10,  "enablement_mw": 350},
    "RAISE6SEC": {"price": 0.95,  "enablement_mw": 1240},
    "LOWER6SEC": {"price": 0.45,  "enablement_mw": 980},
    "RAISE60SEC":{"price": 0.12,  "enablement_mw": 2100},
    "LOWER60SEC":{"price": 0.08,  "enablement_mw": 1850}
  }
}

FCAS Price History

GET /api/fcas/history?service=RAISE6SEC&start=2025-03-14&end=2025-03-21

Gold Table Schema

-- gold.nem_fcas_prices (pivoted from 8 raw columns to long format)
-- interval_datetime TIMESTAMP
-- service           STRING   -- RAISEREG, LOWERREG, RAISE6SEC, etc.
-- price             DOUBLE   -- $/MW/h
-- enablement_mw     DOUBLE   -- MW enabled
-- interval_date     DATE     -- partition key

Tip

FCAS prices in the long (pivoted) format enable straightforward time-series analysis across all 8 services. The raw AEMO data has one row per interval with 8 price columns — the Silver pipeline pivots this to one row per interval per service for query flexibility.

FCAS Revenue Calculator

The platform includes a FCAS revenue calculator for BESS operators:

FCAS Revenue = Σ (EnabledMW_service × Price_service × Hours_enabled_service)

Navigate to Front Office → Battery Dispatch → FCAS Revenue to run the calculator for any DUID over a configurable period.