**What are Ancillary Services?** Short bursts of electricity provided or absorbed to maintain supply-demand balance, ensure grid stability, frequency regulation, and reserves. Grid operators pay assets to remain available and compensate for actual dispatch.
**Key Service Types:**
1. **Frequency Regulation** - Second-by-second adjustments to maintain 50Hz/60Hz
2. **Spinning Reserves** - Capacity available within minutes for contingencies
3. **Non-Spinning Reserves** - 10-30 minute response capacity
4. **Voltage Support** - Maintaining voltage levels across the network
### Revenue Structure
**Two Payment Streams:**
1. **Capacity Payments** - Paid just for being available ($/MW)
2. **Energy Payments** - Paid when actually dispatched ($/MWh)