There are two forms of Firm Frequency Response:
Static Firm Frequency Response (SFFR)
SFFR is the simplest and most widely used form of frequency balancing services in the UK. Participants agree to respond to a drop in the frequency from 50Hz to 49.7Hz by reducing consumption for a period of 30 minutes. These irregular events are often caused by power outages and can happen anywhere between 7 to 12 times each year.
Some businesses already have suitable assets that can earn revenue from Static FFR. Due to the higher level of certainty and the limited number of events, this is one of the most popular ways to enter the frequency response market.
Dynamic Firm Frequency Response (DFFR)
DFFR is continuously provided and is used to manage second-by-second frequency variations. Dynamic response is automatically delivered for all frequency variations outside of the deadband (50Hz ±0.015Hz).
DFFR is arguably one of the most valuable balancing services and operates on a £/MW hour basis. While SFFR maintains frequency between the limits of 49.7Hz and 50.3Hz, Dynamic FFR concentrates on managing the system frequency under normal operating conditions before a fault occurs. The goal is to track precise grid frequency through high and low frequency periods.
Participants in Dynamic FFR are paid to both ramp up their load on the grid and consume more electricity or reduce load during times of frequency imbalance. This is to restore the grid to 50Hz optimum operating frequency. Responders must begin to deliver a response within two seconds. The length of their response typically lasts anywhere between 10 seconds to a few minutes.
What are the requirements?
How are payments made?
Most FFR tenders are made up of an availability fee (£/hr) of price per hour of availability. Some providers also state a nomination fee (£/hr). This payment is made for each hour that is nominated for delivery.
What is the process to tender?
Potential responders must establish an FFR Framework Agreement with the National Grid before participating in monthly FFR tenders. Following the success of their application, providers can submit tenders through an online portal (ARIBA) each month.
These alternate between short-term (month ahead only) and long-term (from month ahead to 30 months out). The maximum contract award is 24 months and the tender must start within 6 months of the first available tender date.