Interoperability is essential for the success of the energy transition and contributes to the investment protection for the users as well as the manufacturers. A normalized use of technical standards for interfaces and communication protocols is a central requirement for cost-effective system integration. Seamless interoperability in the Smart Grid is important, because the change takes place gradually and new components must be integrated into an existing system.
A key factor to enable the successful transition from the present power system towards the Smart Grid is interoperability between power system components. Renewable generation, electric vehicles, smart appliances or industrial assets may only be reasonably integrated within the energy system, if appropriate communication and data model standards are available. Considering the various stakeholders of the system infrastructure and its heterogeneous applications, there is a need for a managed process in order to identify strategically relevant technological fields and assess their interfaces. Here, use cases can provide information on stakeholders, applications and functionalities, and may be attributed to strategic goals formulated in technological roadmaps on specific levels to ensure transparency.
Within the M/490 mandate from the EC to CEN/CENELEC and ETSI, first steps towards standardizing the format of use case documentation, choosing individual standards as well as documenting smart grid architectures have been taken. In the second phase of the mandate, the problem of interoperability was addressed – but only very brief since the mandate ended before this issue was properly solved. Therefore, the issue to properly address interoperability, develop a method for compatibility and conformance testing as well as the procedures themselves are still only islands of automation in the scope of the energy system as a complex requirement.
Information and communication technologies (ICT) may act as an enabler to preserve the level of comfort and reliability within the power system while dealing with these challenges. By complementing the physical infrastructure for electrical energy by a communication infrastructure, the connected assets (e.g. producers, consumers or storages) may be coordinated in a more reasonable way than nowadays. The common term for this vision of the power system is the Smart Grid, may be defined as an “electricity network that can intelligently integrate the actions of all the users connected to it – generators, consumers and those that do both, in order to efficiently deliver sustainable economic and secure electricity supply”
As the share of renewable energy sources in overall energy provision increases, the planning and operation of the power grid – and especially the necessary task of balancing generation and consumption – are becoming more and more difficult. In many cases, a conventional expansion of the existing grids is necessary.
The smart grid approach is aimed at an increasingly decentralised, regional load balance. This is achieved by establishing communication networks between individual components such as distributed generation units, distributed storage systems, flexible consumers, and intelligent buildings. Individual technologies for smart grid solutions are already available today. Now these technologies have to be more widely integrated into distribution grids, systematically linked together, and optimised.
According to the definition of the smart grids in the context of the Technology Platform Smart Grids Austria, "[s]mart grids are power grids that promote energyefficient and cost-effective system operation for future requirements. Thanks to coordinated management, they use real-time two-way communication between
- grid components,
- storage, and
As the energy system and the electricity markets are transformed, the customer’s role changes as well. Smaller photovoltaic (PV) systems, and more recently even battery storage systems, are
being installed on the end-consumer side. As a result, customers are no longer just consumers, but are at times producers as well, or “prosumers”. Prosumers can become part of the smart grid by making their flexibility as an energy consumer and producer available as a service to the local grid and for the overall system, for example in the form of storage or reactive power management.
On an international scale the IEEE Smart Grid Initiative brings together IEEE’s broad array of technical societies and organizations through collaboration to encourage the successful roll-out of technologically advanced, environment-friendly and secure smart-grid networks around the world.
Worldwide, smart grids will be individual solutions tailored to regional needs and requirements. There is no unique solution that can be applied out-of-the-box. Smart grids are composed of diverse building blocks, which jointly provide the locally required features and intended improvements. Therefore, smart grid technology comprises all the components and services that contribute to the transition towards smart grids, from regionally regulated Smart Meters to Big Data analysis enabling anticipatory grid management (load balancing).
The communication means of controlled devices have a prominent role because they are fundamental to coordination and cooperation. Traditionally, three communication 'channels' can be separated:
- the real-time feedback provided by frequency and phase of the AC grid reflecting any imbalance,
- the mostly autonomous and event triggered information exchange (e.g. monitoring and alarming), and
- the communication with grid management systems and user interfaces allowing to apply the automatic balancing and safety mechanisms.
With the introduction of Smart Grid technology a fourth 'channel' is introduced: locally managed device-to-device information exchange.
This new channel is evidently required to realise distributed control. Basically, it merges the features and capabilities of the event triggered and the management channel but does not replace them entirely. Utilising this new channel, the automated balancing and safety mechanisms incorporate the information received in their local decisions, which thereby become more smart. In which way and at what magnitude the received information is integrated has to be carefully coordinated to stop evolving control oscillations prior to becoming critical. A feedback mechanism is required that monitors the taken actions and relates them to the achieved response. As the environment of smart grids is constantly changing, a balance between control stability and adaptability needs to be found. To initialise and re-initialise in case a control reset is required, the self-learning smart control needs to be trained prior to being released. In a real grid, this may jeopardise grid stability. Big Data analysis is most likely required to supervise the operation of smart grids and to intervene in time. Initially, this supervision can implement smart management in a centralised fashion.
In economic terms, electricity (power & energy) is a commodity capable of being bought, sold, and traded. An electricity market is a system enabling purchases, sales and short-term trades. Bids and offers use supply and demand principles to set the price. Long-term trades are contracts similar to power purchase agreements and generally considered private bi-lateral transactions between counterparties (also called OTC-trades).
Electricity liberalisation refers to the liberalization of electricity markets. As electricity supply is a natural monopoly, this entails complex and costly systems of regulation to enforce a system of competition.
During the 1990s, when most of the national electricity and natural gas markets were still monopolised, the European Union and the Member States decided to open these markets to competition gradually. In particular, the European Union (see Liberalisation of the electricity and gas markets, European Commission 2012) decided to
- distinguish clearly between competitive parts of the industry (e.g. supply to customers) and non-competitive parts (e.g. operation of the networks);
- oblige the operators of the non-competitive parts of the industry (e.g. the networks and other infrastructure) to allow third parties to have access to the infrastructure;
- free up the supply side of the market (e.g. remove barriers preventing alternative suppliers from importing or producing energy);
- remove gradually any restrictions on customers from changing their supplier;
- introduce independent regulators to monitor the non-competitive sector.
European electricity markets operate on various levels. Wholesale markets (electricity suppliers) differ in structure and organisation from retail markets (end-consumers). Bilateral ("OTC") trading is also an option. Markets vary in geographical scope and based on their time scale, ranging from long-term contracts and day-ahead trading to intra-day and real-time balancing markets.
Different entities are responsible for generating electricity, operating the transmission system (Transmission System Operators, TSOs) and operating the distribution system (Distribution System Operators, DSOs). The diagram below gives an overview of the players on the Austrian electricity market and their interrelations.
(Source: e-control Austria)
CSA: Clearing and settlement agents
BRP: Balancing rensponsible party
The IES-method serves as a service: Interoperability will help substantially to create solutions for the participants of the energy market to leverage smart resources across national borders and to participate in changing energy market structures. Transparent methods to harmonise technical specifications and profiles with a clear focus on the needs of the customers will create a real European Market Place. The harmonised use of standards and profiles will lead to improved demand side management solutions, better prosumer interaction and faster integration of microgrids. It will push flexibility and energy exchange across borders and it will increase transparency. Interoperability will foster competition and contribute to decreasing prices for better products.
A virtual power plant is a cluster of distributed generation units (such as microCHP, wind-turbines, small hydro, back-up gensets etc.) which are collectively run by a central control system. The operation mode optimizes different goals , such as energy trading or technical goals (e.g. peak load shifting).
A VPP is able to act on behalf of a multitude of DER assets to generate optimal commercial value from the portfolio in the wholesale electricity markets. VPPs may create value by mitigating financial trade risks and through operational optimisation by the whole portfolio of DER assets under management.
In the FENIX project, the activities in the commercial wholesale market and system management services are described respectively as “commercial” and “technical” activities, which derive the corresponding roles of “Commercial VPP (CVPP)” and “Technical VPP (TVPP)”.
The CVPP agent acts on behalf of a multitude of DER assets to generate optimal commercial value from the CVPP portfolio in the wholesale electricity markets (with the exception of ancillary service and balancing markets organised by transmission network operators).
The TVPP has the function of characterising the operating parameters of DER in a particular network location; it aggregates local network and DER capabilities to provide a picture of the capabilities of the distribution network at its interface with transmission.
A VPP is also a complex system requiring a complicated optimization, control, and secure communication methodology.
Industry Alliance VHPready e.V. developed the VHPready 4.0 standard for VPPS, a platform for exchange and cooperation between key players in energy system transformation. The goal is the development and dissemination of an open and international industrial standard for interoperability and controllability of system components in virtual power plants.
First deployments have been started by the alliance, e.g. communication within the German WIndNode initiative, a large scale smart grids model region in the Northeast of Germany, is based on the VHPready 4.0 standard.
In order to support large scale integration among all these playsrs, the IES Austria project started the development of specifications of a normalised use of standards, for example IEC 61850. These specifications are developed within the framework of IT integration profiles. Actor-transaction diagrams, such as in the example below, represent one part of an integration profile, defining the relations and transactions between two actors. The provided example shows the transmission of a generation schedule from the operator of the virtual power plant to the decentralised generation unit.