Krzysztof Zagrajek

Due to the growing importance of ensuring energy security while using low-carbon sources of electricity, it is necessary to use energy storage technologies. However, sometimes it is not possible to use stationary battery energy storage systems. In such cases, mobile energy storage facilities are an alternative solution. This article presents a methodology for assessing the cost of delivering or not delivering energy to the end user when demand will be covered by mobile electricity storage facilities. It is proposed that financial compensation for the end user should depend on hourly revenues and a bonus coefficient. Next, the cost of delivering energy to the end user was minimized by changing the nominal capacity of the mobile energy storage battery and the number of vehicles, taking into account technical and spatial constraints. The results show that the average cost of delivering energy from mobile energy storage systems can vary from 0.4 EUR/kWh to even 184 EUR/kWh, with an average cost of 9.1 EUR/kWh. However, it should be emphasized that a fleet of vehicles with mobile energy storage facilities can only provide energy for a limited period of time. Out of all the simulations carried out, the best results were achieved for the 1 and 4 h power outages; the level of successful electricity provision was above 80%.

This study presents the analysis of voltage and frequency dynamics in a smart microgrid through the dynamic model developed on the experimental microgrid situated within the PrInCE laboratory at the Polytechnic University of Bari. The main aim of this work is to investigate the network responses to substantial perturbations, such as short-circuits, that systems can experience. Through a preliminary offline analysis, various operational conditions are considered to provide a comprehensive overview of voltage and frequency variations caused by these events across network nodes. The feasibility of an operational condition could be analyzed simply comparing these nodal trends with the settings of the corresponding protection relays, giving a wide practical comprehension of the system dynamical behavior. Applying this method to a large number of operating points, it is possible to explore and analyze in a practical manner the operating hyperspace of the entire system. From this knowledge it will be possible to study proactive control methodologies to uphold the dynamic integrity of the microgrid.

This article presents the possibility of using mobile electric energy storage to improve energy security for end users. Due to the ongoing energy transition and the increasing number of challenges regarding the need to keep the power system operating correctly on the one hand and the further promotion of the development of renewable energy sources on the other, it is necessary to consider whether the use of mobile energy storage facilities would solve some of them. The paper proposes how such a mobile energy storage should function and develops an example of the energy services it could provide. Based on actual data from the Warsaw University of Technology facility, it was also verified that it is possible to use such a solution to support power supply to the end user during unfavorable events occurring in the power system.

Load frequency control (LFC) is one of the most important tools in power system control. LFC is an auxiliary service related to the short-term balance of energy and frequency of power systems. As such, it allows the acquisition of a central role in enabling electricity exchanges and providing better conditions. The classification of LFC can be carried out from different angles: we can enumerate, among others, the type of control used. The following types of control are presented in this review: classical, optimal, and robust control. More advanced controls can also be used for classification: fuzzy logic control, ANN control, genetic algorithms, PSO control, etc. The influence of renewables and power control tools like FACTS is also considered as a category to be analyzed. The last classifications are related to two important subjects—the influence of DC links on LFC efficiency and the dangers of cyberattacks on the LFC.

This paper presents the concept of using electric vehicles (EVs) as a countermeasure to deal with the negative effects of power rationing when electricity demands become difficult to meet due to unfavorable electrical system operating conditions. At present, an energy storage is widely used to maintain the stability of electricity supply in facilities whose main source of energy is renewable energy sources (RESs). However, we must not forget that electric vehicles are also electricity storage facilities, but they are not always available due to their mobility. With properly developed strategies, they can be used in electricity management processes, for example, by reducing their consumption during charging using smart charging technology, or by providing electricity from their batteries using vehicle-to-building (V2B) technology. Thus, this article presents a research methodology that treats electric vehicles as a remedy for eliminating power constraints. It consists of five main steps, including two algorithms for deciding how to deploy EVs during power rationing periods. An efficiency factor for eliminating these constraints was also introduced. The results showed that the use of smart charging or V2B technology in EVs can reduce the number of potential hours in which certain power levels are exceeded by up to several tens of percent. This means that in the future, with the significant development of electromobility, such a way of dealing with power constraints could be an alternative to conventional solutions like diesel generators.

The functioning of universities during the energy transition can be quite a challenge for them. On one hand, it is necessary to pursue a sensible policy of sustainable development based on the growth of their own renewable energy sources and electricity storage facilities. The aim of such measures is to increase self-consumption and ensure partial energy self-reliance while reducing carbon dioxide emissions into the atmosphere. On the other hand, the current geopolitical situation has indicated significant problems in the energy sectors of European Union countries. From the point of view of decision-makers at universities, the main concern should be ensuring the continuity of the operation of such a facility, including ensuring the energy security of the sites under management. Thus, it is necessary to merge these two areas and consider the development of an energy management strategy on university campuses oriented towards the development of distributed generation resources. For this purpose, one of the methods of multi-criteria decision aiding the ELECTRE I was used. As a result of the analyses, an energy management strategy was established for the main campus of the Warsaw University of Technology, which simultaneously ensures energy security and sustainability efforts.