In an ideal “post-lignite” era, citizens will have an active role in the production, storage, sale and generally in the management of clean energy, they will be members of energy communities, they will enjoy the benefits of using “smart” grids, but also microgrids, acquiring energy independence in cases of failures in the core network, and achieving an improvement in its cost. In addition, they will have in their homes “intelligent” electricity meters and load controllers (agents) without central control, who will perceive the state of the network from the neighboring meters and will decide autonomously which consumptions to isolate, making time shifting of load, without affecting the quality and with the least burden on the network. Imagine yet another “smart” household network that will store in batteries the over-sufficient amount of energy produced to use it when needed, such as for example, for charging an electric car, even at night, or in a “smart” washing machine, which is automatically put into operation at the time when the electric charge returns to a certain level.
And if all this seems to some very distant or utopian, to the members of the SmartRUE team of the Laboratory of Electricity Systems at the School of Electrical and Computer Engineering of the NTUA, it is simply their everyday life. This everyday life is described today to the startupper through its space, the team that focuses research on the energy transition. SmartRUE (from the Smart grids Research Unit of the Electrical and Computer Engineering School) was established and operates under the supervision of Professor Nikos Hadjiargyriou and consists of 40 people, postdoctoral scientists, doctoral and postgraduate students and highly qualified researchers, while it is technically and administratively supported by the staff of the NTUA Laboratory
The initiator and founder of the team, Professor Hadjiargyriou, has been included for 3 consecutive years (2016-2019) in the 1% of researchers with the most cited publications worldwide (Highly Cited Research), in the list of Thomson Reuters organization with the most influential scientists worldwide with their research, he has served as president and CEO of HEDNO and is considered one of the pioneers of microgrids, since he coordinated in the 2000s the first European microgrid research programmes.
In this context, the first microgrid pilot installations were carried out in Europe, among them the microgrid in the area of Gaidouromandra, Kythnos, which was built by CRES and was reinforced with intelligent load controllers and other innovative applications. The professor now returns to Kythnos with his team for new pilot applications designed in a non-interconnected island electrical system. It is worth noting that he was honored in 2020 with one of the most important the most important international awards, the Global Energy Prize for its contribution to the field of energy.
Smart grids from a smart team
In an attempt to define “smart” grids, Prof. Hadjiargyriou describes electricity networks that can intelligently integrate the actions of all connected users-producers, consumers and those who do both in order to provide effectively sustainable, economical and secure electricity supply. The microgrids that belong to the “smart” networks are low and medium voltage networks that include local resources, batteries and flexible loads with their operation subject to constant control. Microgrids are based on the energy communities, which are dealt with by several members of the team, such as PhD candidate Alexandros Chronis, who works on the technical and social part of creating a community. The members of the group have even set up their own energy community. The main advantage and at the same time characteristic of microgrids is that they can work either interconnected with the network, or autonomously, providing greater security and reliability in consumption, even in cases where the network faces problems.
What the professor describes can be seen in the laboratory in miniature. On the roof of the building there are photovoltaic panels, but also a small wind turbine that the researchers built on their own for the needs of their experiments. They are all connected to an alternating voltage network through power inverters and supply the basic part of the laboratory which is a microgrid, which additionally includes batteries, controlled loads and controlled interconnection with the local network. The inverters are properly controlled to allow the operation of the system, either with the grid-tied network, or in island mode with a quick transition from one state to another. In the laboratory, wind turbines have been constructed for charging batteries or for connection to the network, with impeller diameters up to 4.3 meters This knowledge is also passed on by the members of the team to high school students through educational seminars and wind turbine construction workshops in schools. They have already visited 6-7 schools. The laboratory’s equipment includes a 3D printer on which researchers print wind turbine blades.
The professor and his team have installed photovoltaic panels and small wind turbines and have organized educational seminars in developing countries in Ethiopia, Nepal, India, Latin America and other parts of the world. At the moment they are “running” a fairly ambitious European program for the installation of microgrids in environments with wild climatic conditions in isolated areas in India, as a product of Indo-European cooperation together with Danish and English colleagues.
The laboratory also has a solar radiation simulation device for experiments on photovoltaic panels under special operating conditions or when the weather does not allow it. For simulation, a valuable Real time digital simulator device is also offered, which is located in a prominent position in the laboratory. “It is difficult to study a large electricity system in real operating conditions, so we do computer simulation”, explains the PhD researcher Dimitrios Lagos who deals with real-time simulations, power electronics control, dispersed production and microgrids, and continues: “We manufacture suitable models and “run” them in real time on powerful parallel processors. This simulation allows us to study the behavior of networks in real time, giving us the ability to connect real power devices to the simulated electrical networks. So we combine the advantages of simulation (flexibility, safety) and laboratory tests using the real device.” The connection of the equipment to the simulation unit has been undertaken, among others, by PhD candidate Alkistis Kontou who is an expert in power electronics and controls the inverters at the points of connection of RES to the network.
Microgrids for durability
The professor with SmartRUE have experimented with small dispersed power plants and have installed microgrids in various places, such as a seaside camping cooperative of 170 small prefabricated houses in Rafina. The system designed by the NTUA allows dispersed units and consumption devices to “negotiate” without central control aiming at the optimal distribution of available energy and is based on software, which is implemented to “intelligent” load controllers (agents). “The controller is scalable with various serial and one USB port and has the ability not only to monitor but also to control several devices. It is designed for on-premises installation and is equipped with a screen on which messages are displayed to the consumer about the state of the system, the consumption and the cost of energy. This information is also available to them via the internet,” explains Professor Hadjiargyriou, showing me such “smart meters” in the laboratory.
Hearing about “intelligent” networks and microgrids, one cannot help but ask about the possibility of transforming the existing electrical system where production is concentrated and power flows in one direction, in a “smart” network, where the power production is two-way, power flows in any direction while increasing the reliability of the electrical system, but also its durability, especially in cases of natural disasters.Dimitris N. Trakas, another member of the team that has completed his PhD in the assessment and enhancement of the resilience of Electricity Systems, explains the value of smart grids for the resilience of energy systems in natural disasters, such as fires: “It is of great importance to see the evolution of fire and to accurately assess where and when it will hit the grid. In cases of extensive failures, dispersed or mobile units are useful to feed it where it is interrupted. At the end of the fire, if the network is digitized you can locate the site of the fault and quickly rush to restore it.” In his intervention, Professor Hadjiargyriou comments that such systematic studies have not been carried out so far in Greece and that the only measure being discussed is undergrounding.”Imagine that in a natural disaster the power supply is interrupted because a part of the system is affected. Then this department is isolated and the network continues to work by activating its own local sources, serving the most critical loads. This happened, for instance, on the Sendai microgrid in Japan, when the Fukushima accident took place”, he adds, pointing out that the philosophy of resilience is now beginning to change internationally in this direction.
The discussion with the SmartRUE team and professor Hadjiargyriou never ends, on the contrary, it now begins, since the energy transition, especially in a decentralized model based on the investment of many in inclusive RES, has entered for good in the public debate. Heading towards the exit of the workshop, Mr. Hadjiargyriou speaks with pride about his team, but also about the efforts he has made to develop and keep it within the country. “We hear from the State about reversing the brain drain, about brain return, but in essence there is no help. If it were not for the European research programmes, we would have lost even more brilliant young scientists”, comments the eminent scientist. At the same time, the laboratory hosts two researchers from Finland who have just arrived and will stay in Athens for a month, within the framework of a European program, in order to be trained by the professor and his team in the technology of “smart” networks and microgrids. “Our laboratory is sought after and is included in the best international laboratories of scattered production and microgrids”, he says and this is evidenced by the countless awards and distinctions he has won from time to time.
