Skip to content

Conceptual Model and Terminology

This section provides a common understanding of the key concepts used in the Flexibility Information System (FIS) documentation.

It explains how party types and resources are represented in the FIS conceptual model and how they relate to each other.

By understanding the concepts introduced here, users can better interpret the data model, API resources, and process descriptions presented elsewhere in the documentation.

The conceptual model

The simplified conceptual model below illustrates some of the most central concepts in the FIS and the relations between them. The model serves as an overview when we introduce concepts and abbreviations throughout the documentation.

The conceptual model is based on terminology from the Network Code on Demand Response (NC DR) and in this section we describe how we have chosen to interpret these concepts so far.

Conceptual model

Note

Throughout this section, the names of resources (such as CU, TR, AP or SPG) are linked to their corresponding API resources descriptions. These links provide the fields, validation rules, and other technical details for each resource.

Likewise, the names of parties (such as SP, SO, ES, BRP and EU) are linked to the party type definitions in the Auth section, which describe their authentication model and authorization rules.

What is a controllable unit?

NC DR defines a controllable unit like this:

Article 2:

(21) 'controllable unit' or 'CU' means a single power-generating module and/or demand unit pursuant to Article 2(5) of [RfG NC 2.0] and Article 2(4) of [DC NC 2.0];

A controllable unit (CU) is a unit in the power system that can be actively controlled to produce, consume, or store electricity, and is therefore a source of flexibility in the system.

A CU can be:

  • Power-generating module: a unit that produces electricity, such as a power plant or a wind farm.

  • Demand unit: an electrical installation that consumes electricity, such as an industrial boiler or an EV charger.

  • Energy storage system: a unit that can both produce and consume electricity, such as a battery that charges and discharges depending on system needs.

A service provider (SP) offers flexibility from the controllable unit on behalf of the end user (EU) based on their controllable unit service provider (CUSP) agreement, which authorises the SP to manage the CU for flexibility services.

Technical resources

Each CU consists of one or more technical resources (TRs). A TR is a physical device that generates, consumes, or stores electricity. The CU represents the logical control for these resources, which all relate to the same accounting point.

Note

The NC DR does not define a concept equivalent to a 'technical resource' (TR), but several requirements motivate including TRs in FIS:

  • SPs must describe the type of technical assets used to deliver services (Art. 17(1)(d)), and system operators (SOs) must receive structural and technical data about CUs and service providing groups (Art. 52-54).

  • Prequalification should be simplified when CUs are technically identical (Art. 20(3), 21).

  • When doing CU lookup, the SP can use the TR information to identify the CU more easily.

Connection to an accounting point

In FIS, each controllable unit is connected to a single accounting point (AP). This ensures an unambiguous link between the CU and the balance responsible party (BRP) of the associated energy supplier (ES), which enables imbalance adjustment and settlement.

Knowing the AP where a CU is located also allows system operators (SOs) to know where in the grid it is. As a result they know where flexibility can be activated in the grid.

A service providing group is a collection of controllable units

NC DR defines a service providing group like this:

Article 2:

(26) 'service providing group' or 'SPG' means an aggregation of controllable units or service providing units connected to more than one connection agreement point within the same scheduling area. SPG is defined by the service provider to provide balancing or local services;

A service providing group (SPG) is a collection of CUs. We call the CUs members of the SPG.

Note

The NC DR also includes a definition of a 'service providing unit' (SPU) as a single unit connected to one connection agreement point. We do not include SPU in the FIS. We do not see a reason for this distinction and have thus not modelled it in.

The topological location of the SPG members limits the use of the SPG. If SPG members are close together and all connected to the same part of the grid, the SPG can offer local services such as congestion management. If the members are spread out over a larger area, the SPG can maybe only offer balancing services.

Each SPG is restricted to a specific area by the service provider. The provider specifies this when creating the SPG. We use the term bidding zone, rather than scheduling area used in NC DR, for this area. SOGL tells us that the geographical scope of the scheduling area is equal to the bidding zone. The term bidding zone is widely used and easy to understand for market participants. The Norwegian word for bidding zone is budområde, and in common language also referred to as prisområde. We foresee use of local bidding zones on SPGs used for congestion management. The term bidding zone is thus more flexible and future-proof than scheduling area.

Types of bidding zones

As of now, the bidding zones in the system are the price areas in Norway (NO1-NO5), used for balancing.

We are planning to extend this concept to include other types of bidding zones to facilitate local flexibility markets and possibly congestion management for system responsible.

The end goal would be that we define all bidding zones as topological areas in the common national grid model. This will require a complete national grid model with accounting points mapped to nodes in the grid. This is possible, and in the works by, Elbits but will take time to implement.

There are several other ways to define bidding zones as interim solutions. We will explore these options depending on the needs of market participants.

  • Geographical areas using polygons (lat/long). Most DSO have these in the NODES platform already. This requires that accounting points have a defined geographical location. Many accounting points in Elhub have this today, and for the rest, we can guess based on address etc.
  • Accounting point lists. The SO can provide a list of accounting points that defines the bidding zone. This is more work for the SO and prone to become outdated, but it is precise and easy to implement.
  • Administrative areas such as municipalities or postal codes. This is easy to implement and understand, but not very precise and probably not very useful for the SO.
  • Metering grid areas (MGA). Might be useful for some SOs and cases and we know which MGA all accounting points belong to.

It will also be relevant to define bidding zones that are combinations of the above, to provide a hierarchy of bidding zones for different purposes.

Example with EV smart charges

The diagram below illustrates how CUs and a SPG are related in the context of EV smart charging.

Each charging site is a CU. All chargers at the same site are connected behind the same AP and are operated under a common control module. These chargers are the TRs that make up the CU.

The CUs are then grouped by a SP, forming a SPG. The SPG acts as the interface between the SP and the SO, offering services such as balancing or congestion management.

Each CU (charging site) can respond individually to control signals, while the SPG coordinates all sites to deliver a joint service to the power system.

CU/SPG EV example