About Flexibility Services
Many electricity generator and consumers have the potential to reduce their demand for electricity during peak periods or, conversely, the ability to increase energy supply using existing, on-site power generation assets.
Where there are known constraints on electricity distribution network, DNOs wish to enter into contract with these consumers which will allow them to utilise this demand and generate flexibility in return for financial payment.
Flexibility in Action
Constraints on the electricity network are confined to specific geographical locations, we call these locations Constraint Management Zones (CMZs). DNOs CMZ locations are shown on the locations map.
When we publish a flexibility requirement on our locations pages we provide details of the CMZs operational window that outlines the time of day and the time of year we need flexibility services as well as a forecast of the total MWhs we anticipate needing within the window. Operational windows are generally seasonal to support constraints within summer and winter demand peaks.
DNOs procure Flexibility Services in alignment with the services described in the ENA's Open Network Project DSO ON Service Definitions document.
Four services have been developed by the ENA, each cater to different network requirements.
(ON service definition - scheduled constraint management)
The Sustain service is used to manage peak demand loading on the network and pre-emptively reduce network loading. The requirement windows for provision of these services will be scheduled and fixed at the point of contract.
(ON service definition - pre-fault constraint management)
The Secure service is used to manage peak demand loading on the network and pre-emptively reduce network loading.
Secure requirements are declared a week-ahead each Thursday for the following week (commencing Monday). Payments consist of an Arming fee which is credited when the service is scheduled and a further utilisation payment awarded on delivery.
(ON service definition - post-fault constraint management)
The Dynamic service has been developed to support the network in the event of specific fault conditions, often during summer maintenance work.
As the service is required following a network fault, it consists of an Availability and Utilisation fee. By accepting an Availability fee, participants are expected to be ready to respond to Utilisation calls within 15 minutes. Dynamic availability windows are declared a week-ahead each Thursday for the following week (commencing Monday).
(ON service definition - restoration support management)
The Restore service is intended to help with restoration following rare fault conditions. Such events are rare and offer no warning as they depend on failure of equipment. Under such circumstances, response can be used to reduce the stress on the network.
As the requirement is inherently unpredictable, Restore is based on a premium 'utilisation only' service. This will reward response that aids network restoration, but will pay no arming or availability fees. Participants declared available for the Restore service will be expected to respond to any utilisation calls within 15 minutes and will receive an associated utilisation fee.
Product Summary Table:
|Use Case||Scheduled||Pre-fault||Post-fault||Post-fault network restoration|
|Availability Payment||Yes, for scheduled availability pre-agreed within contract||Yes, arming payment for availabilityat week-ahead||Yes, arming payment for availabilityat week-ahead||No|
|Availability Declarations||Week-ahead. By midnight every Wednesday for the following week (Mon-Sun)||Week-ahead. By midnight every Wednesday for the following week (Mon-Sun)||Week-ahead. By midnight every Wednesday for the following week (Mon-Sun)||Week-ahead. By midnight every Wednesday for the following week (Mon-Sun)|
|Availability Acceptance||Week ahead. By midday every Thurs for the following week (Mon-Sun)||Week ahead. By midday every Thurs for the following week (Mon-Sun)||Week ahead. By midday every Thurs for the following week (Mon-Sun)||Week ahead. By midday every Thurs for the following week (Mon-Sun)|
|Dispatch Notice||Fixed within contract and notice sent 15 minutes ahead of requirements||Fixed week-ahead on acceptance of availability and notice sent 15 minutes ahead of requirements||Notice sent 15 minutes ahead of requirements||Notice sent 15 minutes of requirements|