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Technology and Infrastructure
Grid
The grid refers to the interconnected network of transmission and distribution infrastructure through which electricity flows from generation sources to end-users. Smart grid transitions are reconfiguring grid architecture at multiple levels: at transmission level, new interconnectors and grid-forming inverters are changing how system inertia and frequency regulation work; at distribution level, the proliferation of rooftop solar, batteries, and electric vehicles is turning networks designed for one-way power flow into active systems with bidirectional flows. The concept of the grid is expanding to include communication infrastructure, data platforms, and logical coordination layers alongside the physical wires and transformers.1)
The grid encompasses transmission and distribution infrastructure, control systems, and governance layers; smart grid transitions are making bidirectional flows and distributed coordination central to how grids function.
Why this matters
As electricity systems integrate more distributed resources and digital control, coordinating actors, assets, and data across multiple grid levels becomes more complex. Architecture frameworks provide a shared language for this coordination — allowing engineers, regulators, and market designers to map where decisions are made, which interfaces carry which information, and where interoperability is required. Without such frameworks, standards and regulations risk being designed in isolation, creating gaps and conflicts in system operation. The governance configuration of the grid — who owns what, on what terms, under what rules — shapes what transitions are possible and who can participate in them.
The three major architecture frameworks — SGIRM, GWAC, and SGAM — each decompose the smart grid into layers spanning from physical assets and communications to business processes and regulatory structures, but they differ in emphasis and regional uptake.
Shared definitions
The grid encompasses the physical infrastructure of electricity transmission and distribution — lines, cables, transformers, substations, and switching equipment — together with the communication systems, control architectures, and logical coordination functions that manage power flows across it. In smart grid contexts, the grid often denotes the full socio-technical system: not just the wires, but also the standards, ownership arrangements, operational rules, and data flows that determine how the physical network behaves.
A fundamental distinction separates the transmission system (high-voltage, long-distance, interconnected at national or regional scale) from the distribution system (medium and low voltage, reaching end-users, historically passive and radial in design). Smart grid development is most pronounced at the distribution level, where new actors, devices, and services create coordination challenges the original architecture was not designed for.
| Term | Definition |
|---|---|
| Transmission system | High-voltage, long-distance network connecting large generation sources and bulk consumers across national or regional geographies |
| Distribution system | Medium and low-voltage network delivering electricity to end-users; historically radial and passive, increasingly active with distributed generation and flexible loads |
| Domain | In SGAM, a segment of the physical energy conversion chain: generation, transmission, distribution, DER, and customer premises |
| Zone | In SGAM, a level of the operational hierarchy, from the physical process layer through field, station, operation, enterprise, and market |
| Interoperability layer | In SGAM, one of five levels at which components, systems, or organisations must exchange meaningful information: component, communication, information, function, or business |
| Transactive energy | A control and coordination approach combining economic signals with physical control to balance supply, demand, and network constraints across distributed grid actors |
Perspectives
Actors and stakeholders
Architecture frameworks serve different user communities. Standards bodies and equipment manufacturers use them to define interoperability requirements. System operators use them to assess integration challenges when new resource types connect to the grid. Regulators and policymakers use them to identify governance gaps across system layers. The WG7 analytical work on network architecture and governance maps how ownership structures and decision-making authority configure differently depending on how centralised, decentralised, or distributed the network architecture is, and whether the logical and policy layers align with the physical structure.2)
@@GAP@@ Case examples needed: one case showing how an architecture framework informed a regulatory or standards process; one from outside the EU or North America.
Technologies and infrastructure
Three reference frameworks describe smart grid architecture systematically, each emphasising different dimensions.
The Smart Grid Interoperability Reference Model (SGIRM), revised in IEEE 2030.4-2023, organises smart grid architecture around three integrated architectural perspectives: components and functions (physical assets and their built-in control functions); information and communications (data models and communication systems); and business and economics (market structures, fleet management, grid services transactions, tariffs, and regulatory considerations — a perspective added in the 2023 revision to reflect distributed energy resources and market-based coordination).3) Physical locations are classified as grid-edge (load and customer end), field or substation, and enterprise or cloud.
The GridWise Transactive Energy Framework, developed by the GridWise Architecture Council, applies the GWAC interoperability stack to architectures that use economic and control techniques jointly to improve grid reliability and efficiency.4) The GWAC Stack organises interoperability from basic connectivity and network interoperability at lower levels through semantic and informational interoperability to business objectives and economic or regulatory policy at the upper levels.
Figure 1. GWAC Stack with transactive energy strata. Source: GridWise Architecture Council (2019).
The Smart Grid Architecture Model (SGAM), developed by the CEN-CENELEC-ETSI Smart Grid Coordination Group and the reference architecture for EU smart grid standardisation, represents grid architecture as a three-dimensional model across domains (the physical energy conversion chain), zones (the operational hierarchy from field equipment to market), and interoperability layers (component, communication, information, function, and business).5)
Figure 2. SGAM three-dimensional representation across Domains, Zones, and Interoperability Layers. Source: CEN-CENELEC-ETSI Smart Grid Coordination Group.
@@GAP@@ Case examples needed: one case showing a specific interoperability challenge diagnosed using an architecture framework.
Institutional structures
Beyond technical architecture, the configuration of a grid network has governance implications. Cross-tabulating network architecture (centralised, decentralised, distributed) against the logical layer and the policy layer produces structurally distinct grid types with different implications for ownership, participation, and resilience.6)
Table 1. Network architecture crossed with logical layer — resulting grid coordination types.
Source: Kubeczko (2017), adapted.
| Logical layer | Network architecture | |||
|---|---|---|---|---|
| Centralised | Decentralised | Distributed | ||
| Centralised | Trusted national TSO | Smart meter national ledger (e.g. Sweden) | Blockchain ledger for direct interaction | |
| Decentralised | Markets and market institutions | Markets and market institutions; smart meter ledger by DSOs | Markets and market institutions | |
| Distributed | Bilateral contract solutions | Bilateral contract solutions | Bilateral contract solutions |
Table 2. Network architecture crossed with policy layer — resulting ownership and governance types.
Source: Kubeczko (2017), adapted.
| Policy layer | Network architecture | |||
|---|---|---|---|---|
| Centralised | Decentralised | Distributed | ||
| Centralised | Transmission grid (national monopoly) | Super-grid (global oligopoly) | Publicly owned local grids with local RES feed-in | |
| Decentralised | Private monopolies and oligopolies of multinationals | Distribution grid (local monopoly); suppliers on market | Linked mini-grids; local grid with local RES (e.g. cooperative) | |
| Distributed | People as shareholder; public voting | Local shareholders in monopoly | Linked local grids (locally co-owned, e.g. cooperatives, energy communities) |
@@GAP@@ Case examples needed: one case where SGAM or SGIRM was used in a regulatory process; one from outside the EU.
Distinctions and overlaps
Grid vs network
In electricity sector usage, grid typically refers to physical infrastructure together with its control and communication overlay. Network covers the same technical meaning and also broader actor-networks and logical coordination structures. The two overlap substantially in smart grid discourse, where physical and digital layers are increasingly inseparable.
Grid architecture vs grid operation
Architecture frameworks such as SGAM, SGIRM, and GWAC describe the structural composition of the grid — the layers it contains and the interfaces between them. Grid operation covers how that structure performs in real time, including frequency regulation, voltage control, and balancing. Architectural choices constrain and enable operational possibilities; operational functions are addressed separately in the Operability topic.
Centralised, decentralised, and distributed
These terms describe both physical network topology and governance logic, and the two dimensions do not necessarily align. A centralised physical network is not the same as centralised governance; combinations of the two produce structurally distinct system types with different implications for ownership, participation, and resilience.