Smart Grids: standards for change
Emmanuel Darmois - April 2014
The advent of Smart Grid marks a profound change in electricity networks: architecture, actors and applications. This will be possible through a foundation of open standards-based approaches.
All over the world, for various reasons, power grids are subject to a pressing demand for evolution. While in North America this is primarily to better connect electricity suppliers and allow for the upgrade of aging networks, in Europe it is mainly to be able to implement EU targets 20% for 2020 (20% renewables, 20% reduction of greenhouse gas emissions, 20% improvement in energy efficiency). In all cases, the challenge for existing networks is important and very significant changes (if not a revolution) must be foreseen. This is the challenge that Smart Grids are meant to address.
First, it is useful to note that those new networks are termed "Smart Grid" rather than "Intelligent Power Networks" This is mainly because the Smart Grid focus will be more on "clever" communication than "intelligence": the first target is interoperability, that is to say the capacity of a product or system, whose interfaces are fully known, to work with other (existing or future) products or systems. This is to implement network architectures where different stakeholders are able to interact in cooperation - rather than centralized control of a hierarchical network - to provide new applications.
Somehow, nothing entirely new under the sun (except, of course, photovoltaic) because cooperation between several distribution networks for load balancing is already in service for a long time. What is new with Smart Grids is in particular a greater variety of the actors and of the services they offer: an obvious example is the increased role of renewable energy suppliers.
Electrical networks are complex systems. They are even termed as "systems of systems", thus indicating a particularly high level of complexity. To allow such systems to function, standards are needed - and it takes a lot of them. Indeed, interworking of two parts of a system can only be achieved if the participants (mainly systems or subsystems) are fully informed about the terms of interoperability: the nature of the exchanged flows, the interface description, etc. In the case of an electrical network, interworking involves both a physical exchange (electricity flow) and an exchange of communications (to allow the coordination and control). The standards must govern both.
To define them, one must establish both an institutional framework (clarifying who is empowered to develop the standards) and a technical framework (describing the normalized objects). From an institutional perspective, standardizing the electrical network involves not only the players in the standardization of electricity (in Europe, CENELEC, globally, IEC), but also of Information and Communication Technologies (in Europe, ETSI, globally, many actors such as the IETF for Internet, 3GPP for mobile, IEEE, etc.), and this requires a high level of coordination between the two standardization ecosystems.
In addition, regional differences have generated a de facto involvement of other actors such as the National Institute of Standards and Technology (NIST) in the USA or the European Commission.
Smart Grids were placed into the light by the 2009 Obama plan with an investment of 3.4 billion USD. Part of this funding went to standardization activities coordinated by NIST and bringing together key players - operators, vendors, regulators, standard setters, universities - in the Smart Grid Interoperability Panel (SGIP).
In Europe, the European Commission established a Smart Grid Task Force in 2009 that addressed standardization in the European context. One must remember that only three European organizations are empowered to produce European Standards: CEN, CENELEC and ETSI. In late 2010, the Commission issued a "European Mandate" (M/490) defining the objectives for Smart Grids standardization: the three European organizations have gathered in the Smart Grid Coordination Group (SG-CG) to implement them.
The SG-CG has taken into account the work already done under the European Mandate M/441 for the standardization of the Smart Metering infrastructure, an essential development of Smart Grids that allow for a much more accurate tracking of consumption and, in principle, the possibility to intervene in the management of electricity flows.
The approach taken in Europe and the USA is to coordinate the technical work and to promote the largest initiative of the industry. Thus, the SG-CG is not intended to produce standards, but to identify those that are already in force and those that are missing ("standards gaps") and need to be developed in the Technical Committees (e.g. within IEC, ETSI, etc.).
This coordination has required the development of an innovative common conceptual framework. First, a large number of case studies ("use cases") covering generic or specific aspects of applications were collected and modeled. In parallel, it was necessary to clarify the terminology, identifying the various actors and modeling their interactions, and to display the complex structure of the Smart Grid space into a layered model in order to facilitate the analysis of the use cases.
Modeling actors and roles is an essential pre-requisite in Smart Grids. Indeed, the time is past when most of the interactions between actors (e.g. EDF, E-ON) were made in the context of similar roles (e.g. energy distributor). With the Smart Grid, more complex interactions must be allowed between actors playing different roles (e.g. energy trader and distributor) with more complex market organizations and regulations.
On top of the Actor and Role Model, another key element of this approach is the SGAM (Smart Grid Architecture Model), a three-dimensional representation of the space of Smart Grids, summarized in the figure below, which describes the two main aspects of the area of Smart Grids:
- The "Smart Grid Plane" where the actual implementations of Smart Grid will work. It encompasses two dimensions:
- The "Domains" representing the different components of the physical part of the processing power: Generation, Transmission, Distribution, Distributed Resources, Customer Premises (individuals or companies). Part of the novelty of the model is that it takes into account, under the term "distributed resources", the energy produced locally, including renewable energy, which was an essential prerequisite in Europe.
- The "Zones" that represent the hierarchical levels of the power management system (its computer part) as they move away from the electrical process: Field, Station, Network Management, Enterprise, and Market. An important aspect of the model is the inclusion of the "Market" level that allows to neutrally describe different "business models" without mandating any of them.
- The Interoperability layers describe a Smart Grid system at higher and higher levels of abstraction above the physical layer (the Smart Grid plane): Component, Communication, Information, Function, and Business. These layers allow the analysis of a use case with different approaches according to the needs: for example, the analysis a business model will be done at "Market" level; analyzing communication protocols will be at the "Communication" level.
SGAM: Smart Grid Architecture Model (source SG-CG)
For its consideration of renewable energy and security issues, the model developed in Europe uses a broad approach and it is no exaggeration to say that at this stage, it has become a benchmark for the global standardization of Smart Grids.
One of the expected results of the first phase (2011-2012) of the M/490 mandate was a list of available standards. Indeed, operators and manufacturers, as well as the European Commission wanted to have a clear idea of what could be developed based the existing standards and what was related to the risks to be taken to develop new systems.
Again, a rigorous methodology - based on the SGAM model - has been set up to ensure as complete as possible list of standards and the understandability of the results. To this extent, the SG-CG has identified 24 systems from which all Smart Grid applications (such that they can be considered to date) can be constructed. The aim was not only to identify the available standards, but also to provide insight to those that apply in the context of each of these systems.
The result was a list of over 400 standards produced by more than 50 different organizations. Among these standards, a significant number belong in the field of communication and are produced by Information and Communication Technology (ICT) industry in a large number of different organisms. In addition, a number of standard gaps were identified that will be the subject of future work in the related Technical Committees.
It is interesting to note that a standard can be applied in a context different from the one that has led to its initial production. An example is IP/MPLS, a standard developed for the Internet, now used increasingly within the networks of electricity distribution operators. This standard was developed in a context where a typical application is voice over IP (VoIP) with latency of the order of hundreds of milliseconds. In the context of Smart Grid, it can be used for an application such as tele-protection (which shuts down remote equipments when power grid stability problems occur). Latency in these applications is less than ten milliseconds, which is a new (but possible) usage of a standard in a different technical context.
At the end of the second phase (2013-2014) of the M/490 mandate, a new list of standards will be proposed. It will take into account new developments in standardization, in the last two years, to fill some of the standard gaps identified in the first phase.
Given the complexity of Smart Grid, relevant industries have embarked on a long journey. While many systems will be available in the medium term, others (think for example of an open pan-European market for the instantaneous exchange of renewable energy) will demand more capabilities, in particular regarding interoperability. From this standpoint, standardization will be an accelerator, especially since it was organized in a model where, even if the work to be done is identified early enough, it is actually launched only when the actors are ready, thus avoiding too early development of the standards.
3GPP 3rd Generation Partnership Project
CEN Comité Européen de Normalisation
CENELEC Comité Européen de Normalisation Electrotechnique
ETSI European Telecommunications Standards Institute
IEC International Electricity Commission
IEEE Institute of Electrical and Electronics Engineers
IETF Internet Engineering Task Force
IP/MPLS Internet Protocol/Multiprotocol Label Switching
NIST National Institute of Standards and Technology
SGAM Smart Grid Architecture Model
SG-CG Smart Grids Coordination Group
VoIP Voice over IP