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  • Connections Information- Generation and Storage – Flexible Services

  • Flexible Services are deployed in areas of existing Scottish and Southern Electricity Network (SSEN) network classed as Constraint Management Zones (CMZs). CMZs are geographic regions where network requirements, relating to network security, are met through the use of load variation techniques such as increasing generation or reducing demand. These services are provided to SSEN by a Flexible Service Provider according to contract agreements.

  • Calls for flexibility services

    Find out where we are seeking flexibility services in our licence area and detail of closed/completed opportunities.

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  • Register your interest

    Register here to be notified if we require services in your area.

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  • There are four types of Flexible Service:

    Sustain - Ahead of time procurement of a pre-agreed change in input or output over a defined time period to prevent a network going beyond its firm capacity.

    Sustain (or pre-fault) services are those sought/deployed to manage electrical networks that are approaching a point where the pre-existing network capacity cannot meet power requirements should an outage coincide with periods of highest demand and the system’s firm capacity (post outage) is lower than the demand.

    Traditional reinforcement techniques increase overall capacity across all time periods by including an additional circuit or by up-rating an existing one. Flexible techniques do not seek to increase capacity but rather reduce or time-shift demand to avoid capacity constraints. Since capacity constraints only occur at periods of maximum demand, and only when this coincides with an outage, it means that pre-defined services can be procured in advance to manage these events. SSEN will procure these services based on a four-year contract term with the opportunity to extend by one year.

    Secure – Ahead of time procurement of the ability to access a pre-agreed change in the Service Provider input or output based on network conditions close to real-time.

    In the same manner as Sustain activities, SSEN will procure ahead of time the required power injection/demand response services from available DER providers based on network conditions to manage pre-planned outages. This style of service will be appropriate for implementation across wide and locally specific areas, dependant on the maintenance scenarios affecting the network. SSEN will procure these services based on a one-year rolling contract limited to a maximum five-year term.

    Dynamic – Ahead of time procurement of the ability of a Service Provider to deliver an agreed change in output following a network abnormality.

    SSEN will seek to procure Dynamic services ahead of time from providers able to deliver an agreed change in output to avoid, or following, a network fault. For example, in N-1 scenarios, to avoid overloading of the second circuit or to constrain loadings during restoration or repair scenarios.

    Restore – Instruction following a loss of supply for a provider to either remain off supply, or to reconnect with lower demand, or to reconnect and supply generation to support increased and faster load restoration under depleted network conditions.

    SSEN will procure Restore services ahead of time from providers able to either remain off supply, to reconnect with lower demand, regulate frequency and voltage or to generate into a network zone isolated from the main fault to support increased and faster load restoration within a specific network area. SSEN will procure these services based on a one-year rolling contract limited to a maximum five-year term.

    North Map

    2021 SSEN Procurement Statement

    All Flexible Services that SSEN intends to procure in the next financial year fall within the types listed above, covering reinforcement deferral, pre-fault and post fault services across our licence areas. We also expect to trial a new ‘stability’ service on the Western Isles, designed to reduce reliance on diesel generation by enabling increased utilisation of intermittent renewable generation capacity during outage scenarios.

    A table containing the specific services we expect to tender for in each geographical/network zone can be found in the ‘SSEN SLC 31E – Flexibility Services Procurement Statement’ on our Flexible Solutions Document Library website. This will also include any detail currently available from our forecasting on the size and expected volumes required and maximum connection voltage for any providers wishing to respond to the tenders. Importantly, all SSEN Distribution CMZ services are technology-agnostic. As such, providers of storage, generation, demand-side response or energy efficiency services can respond to any tenders.

    Importantly, whilst this Statement sets out a ‘snapshot’ of the potential requirements for Flexible Services, SSEN will continue to review schemes throughout the year that may be triggered by, but not exclusively, changing network conditions, load growth and maintenance updates, all of which could identify new opportunities as well as nullify or replace schemes included herein.

    Flexibility Services contracts in all zones tendered will generally be multi-year contracts based on either: 

    • a one-year rolling agreement, capped at a maximum of five years; or
    • a four-year agreement, with an optional one-year extension.

    The capping of contracts to five years is in line with industry best practice detailed in the Open Networks WS1A Product 4 2019 report available here:

    https://www.energynetworks.org/creating-tomorrows-networks/open-networks

    In addition, SSEN may choose to re-tender existing zones when yearly contracts expire/approach the rolling over period should new market applicants become available. These zonal contracts have all been placed under a one-year rolling agreement, capped at five years. Some zones may be retendered during this time and details on these zones are included below.

    We will keep this under review and engage on any changes that may be appropriate as the market evolves and develops, or as new recommendations are made through the Open Networks Project.

    Overhead Lines in fields

    Flexibility services will play a big part in avoiding the need for expensive reinforcement to accommodate the growth in low carbon technologies, helping to keep costs down for customers.  So as part of our commitment to flexibility we are moving to a proactive flexibility position, extending the use of flexibility to our entire network.  We want to hear, ahead of need, from existing (or potential) flexibility providers in our license areas who control assets that could provide solutions.  This will allow us to better assess the opportunities to purchase flexibility and react more quickly as and when the need arises. 

    In addition to our register we are also committed to displaying new zones which can be seen from the link below; 

    Current Calls for SSEN Flexibility Services

    As part of the SSE Group, SSEN is a principal partner of the UK Government’s hosting of COP26, the international climate change summit scheduled to take place in 2021, which will have a key role in focusing and driving international decarbonisation efforts. Through the setting of ambitious 2050 and 2045 Net Zero targets, the UK and Scottish Governments have respectively demonstrated leadership and SSEN Distribution is committed to developing the electricity Distribution networks necessary to achieve these targets.

    Flexibility is a fundamental strand of this work and, building on the work to date and the collaborative efforts across the industry, primarily through the Energy Network Association’s (ENA) Open Networks Project, SSEN Distribution is driving improvements and developments to embed and continue to maximise the potential for Flexibility Services where this economically and efficiently delivers the smarter networks necessary to achieve Net Zero.