Series of Articles: Interoperability – What is it, what challenges, and what benefits can be expected?

Integrating controllable loads into the energy system is one of the current topics in the energy industry. The smart charging of electric vehicles is crucial in this context and at the same time poses new challenges. Interoperability plays a central role in enabling smart charging with different components. This was investigated at the FfE as part of the unIT-e² research project.

What is interoperability

The topic of interoperability first drew scientific attention in the military sector. However, it is now being studied in a wide variety of areas, particularly because of digitalization, and different definitions have been formulated. These differ mainly due to the respective field of application. An appropriate definition for the integration of electric vehicles is that of the Institute of Electrical Engineers (IEEE), the International Electrotechnical Commission (IEC), and the International Standardisation Organization (ISO) [1]:

“[Interoperability is] the ability of two or more systems or components to exchange information and to use the information that has been exchanged.” – (Widergren et al., 2019)

Interoperability therefore means that systems can exchange, interpret, and further utilize information. Interoperability goes beyond mere compatibility or connectivity, which is achieved by adapting systems to a single, specific system. On the contrary, interoperability is based on common standards and the standardized interpretation of information across system boundaries. Interoperability can be divided into technical, syntactic, semantic, and organizational levels [2]:

• Technical interoperability: means that information can be exchanged between systems and considers hardware, software, and infrastructure.
• Syntactic interoperability: exists when data is exchanged using standardized file formats and structures.
• Semantic interoperability: means that data can be used and interpreted, whereby the focus is on interpretability by different people.
• Organisational interoperability: describes the efficient communication of organizations across different infrastructures.

What challenges can be expected?

As the stages of interoperability and the multitude of definitions already show, the topic is highly complex and poses various challenges for implementation. On the one hand, uniform standards must be used and adhered to by the various manufacturers. On the other hand, this does not necessarily lead to interoperable systems, as products are designed for different application scenarios with different standard variants. As a result, interoperability is possible in the development process under test conditions, but not beyond [3]. In addition, complexity increases due to the high number of systems and constant progress in further development [4].

To create interoperable systems in this environment, the cooperation of all parties involved is essential. However, these usually have different interests and perspectives. To realize interoperability despite this, common overarching goals must be defined for development, i.e. interoperability must be in the interests of all those involved to a certain extent [1]. However, the extent to which the interoperability of a system can be enforced without compromising other aspects, such as general functionality, must also be weighed up [3].

What are the benefits of interoperability?

Interoperability generally offers clear advantages. Firstly, system performance, efficiency, and security can be increased. Secondly, customer participation is improved, and innovation is accelerated [1]. Interoperability is particularly relevant in areas where a seamless exchange of information must be guaranteed, such as in the healthcare sector [5].

However, the topic is not only important for functioning communication between organizations and institutions but also in the everyday life of a digitalized society to be able to use different technologies without any problems. Without interoperability, technological solutions are separated from one another. Isolating systems from each other in this way means that the full potential of the solutions cannot be utilized [4].

One discipline that is particularly concerned with the development of interoperability is system-of-systems engineering (SoSE). A system-of-systems describes a system that is composed of different systems to form a whole. A high level of interoperability is required to enable smooth interaction at the interfaces of these systems. For this reason, interoperability is one of the most important criteria for systems in the SoSE field [6].

Interoperability is key for e-mobility

Interoperability has a positive effect on various aspects, especially in the field of e-mobility. On the one hand, charging station operators can become more independent of individual component manufacturers thanks to standardized communication protocols. On the other hand, reliable and uncomplicated charging processes create a positive perception of e-mobility among users and the public, thus also promoting positive market development. Interoperability is also important to connect electric vehicles with other important components of the energy system, such as smart metering systems and energy management systems. Interoperability is therefore a fundamental element for the further development and ramp-up of networked electromobility.

However, e-mobility is also a rapidly developing area, characterized by a wide range of use cases for charging processes and other services. The expansion of charging options from uncontrolled charging to controlled charging is also adding new participants and systems. For this reason, various hurdles to interoperability must also be overcome in the field of electromobility.

Learn how interoperability can be measured in part two of the Interoperability series.

Literatur

[1] Widergren, S., Melton, R., Khandekar, A., Nordman, B. & Knight, M. (2019). The Plug-and-Play Electricity Era: Interoperability to Integrate Anything, Anywhere, Anytime_. IEEE Power and Energy Magazine_, 17(5), 47–58. https://doi.org/10.1109/MPE.2019.2921742

[2] Rezaei, R., Chiew, T. K., Lee, S. P. & Shams Aliee, Z. (2014). Interoperability evaluation models: A systematic review. Computers in Industry, 65(1), 1–23. https://doi.org/10.1016/j.com-pind.2013.09.001

[3] Kasnuic, M. (2001). Measuring Systems Interoperability Version 1.0. Software Engineering Institute Carnegie Mellon University

[4] Motta, R. C., Oliveira, K. M. de & Travassos, G. H. (2019). A conceptual perspective on interoperability in context-aware software systems. Information and Software Technology, 114, 231– 257. https://doi.org/10.1016/j.infsof.2019.07.001

[5] Rezaei, R., Chiew, T. K., Lee, S. P. & Shams Aliee, Z. (2014). Interoperability evaluation models: A systematic review. Computers in Industry, 65(1), 1–23. https://doi.org/10.1016/j.compind.2013.09.00

[6] Axelsson, J. (2020). Achieving System‐of‐Systems Interoperability Levels Using Linked Data and Ontologies. INCOSE International Symposium, 30(1), 651–665. https://doi.org/10.1002/j.2334-5837.2020.00746.x