Frequency response services
As part of our licensing obligations, we keep the electricity system stable by maintaining the frequency close to 50Hz, within a 1% range. To do this, we ensure enough power is available to handle any likely changes in supply or demand.
There are two categories of frequency response:
- Dynamic Response continuously adjusts to normal, second-by-second frequency changes.
- Non-Dynamic Response activates only when frequency moves beyond a set limit.
We actively procure the following response services:
| Service | Speed | Duration | Direction | Purpose |
|---|---|---|---|---|
| Dynamic Regulation | 10 seconds | Up to 60 minutes | High and Low | Pre-fault service |
| Dynamic Moderation | 1 second | Up to 30 minutes | High and Low | Pre-fault service |
| Dynamic Containment | 1 second | Up to 15 minutes | High and Low | Post fault service |
| Static Firm Frequency Response | 30 seconds | 30 minutes | Low | Post fault service |
| Mandatory Frequency Response | 10 to 30 seconds |
Low Frequency: 30 minutes High Frequency: indefinite |
Bundled High and Low | Designed to resolve all issues with the one service. A replacement service is being investigated |
| Commercial Frequency Response | Varies | Varies | Varies | Suite of bespoke, bilaterally arranged frequency response contracts |
Static Firm Frequency Response (SFFR)
Static Firm Frequency Response (SFFR) is a non-dynamic frequency response service used for balancing grid frequency in real time.
Dynamic Services (DC/DM/DR)
Dynamic Containment (DC), Dynamic Moderation (DM), and Dynamic Regulation (DR) make up our suite of Dynamic Response Services.
Mandatory and Commercial Frequency Response (MFR/CFR)
We are starting a major reform of these services and welcome your input.
Future of response services
We are investigating what a new, faster-acting frequency response product may look like, and how it could form part of a new suite of frequency response products.
Response Stacking Guidance
This document explains how NESO and providers can unlock stacking of the Dynamic Frequency Response (DFR) services (Dynamic Containment (DC), Dynamic Moderation (DM) or Dynamic Regulation (DR)) or Static Firm Frequency Response (FFR) with bid-offer acceptances (BOAs) in the Balancing Mechanism (BM) or other Balancing Services.
Accessing frequency data
Our extranet shows live demand and frequency data from the past 60 minutes.
For detailed historical frequency data (from 2014, at 1-second intervals), visit the NESO Data Portal.