Sustainability and GHG reduction are the pivotal points of any future mobility. The European policymakers prioritised the BEV technology from 2035 onward. This decision was based on the universal consensus that the BEV technology offers the highest efficiency and that sufficient green energy will be available on time. In this study, the authors will analyse the feasibility of this concept. Due to the stochastic availability of renewable power, a reliable power supply requires adequate storage capacity at the necessary scale and time. The other universal statement is that the production of e-fuels is too inefficient to compete with BEV technology. Based on different publications, the authors are convinced that only chemical storage can fulfil the requirements nationally or globally. The inevitable first step of this energy conversion is water electrolysis, energised by renewables. The losses occurring during the production of green hydrogen are an unavoidable burden on green electricity production. Due to the availability of the produced hydrogen, these losses do not count toward producing e-fuels like methanol, methane, and ammonia. In that case, the baseline of any efficiency comparison alters, and alternative and e-fuels will severely challenge the BEV technology in multiple applications and locations. These fuels will allow further improvements in the ICE technology. The most important finding of this study is that the investigation of separated sub-systems will not deliver the optimum solution for mobility. Only a holistic approach considering the interactions between power generation, power storage, and propulsion technology leads to reliable answers, and hydrogen is the key element of the solution.

Similarly to many countries of the world, photovoltaic systems play an increasingly important role in electricity generation in Hungary, contributing greatly to the climate, environmental and sustainability goals of the energy transition. As a result of numerous factors, photovoltaic technology is used not only more and more widely but also in increasingly decisive quantities and proportions. Due to the intermittent nature of solar energy, photovoltaic generation varies both in space and over time and consequently poses a serious challenge to system management, especially due to dynamically developing capacities. The imbalances caused by uncertainty cannot be addressed by scheduling alone without the possibility of energy storage, which, with its numerous services and applications, is able to provide the flexibility necessary for the smooth operation of the system. Among the available energy storage systems, power-to-gas technology (i.e. converting electricity produced from renewable energy sources into a gaseous energy carrier) is emerging as a practical solution with high potential for the integration of variable renewable energy sources. The gas produced in this way, which can be stored and transported, can be used in many areas and sectors of energy use, such as transport, home heating and cooling and industrial processes, and can now also provide an effective solution for grid stability and scheduling. The aim of the present research is to present the potential amount of green hydrogen that can be produced by proton-exchange membrane technology (PEM) in connection with schedule-related downregulation, considering the climatic conditions and the total photovoltaic power plant capacity in Hungary. The novel, practical benefit of the research lies in the fact that it determines practically relevant characteristics in relation to the interconnections of solar power plants in Hungary and power-to-gas technology for transmission system operators, the key players of the energy market and decision-makers. This knowledge will not only help companies investing in solar power plants and power-to-gas technology from an economic point of view but can also contribute to the market-related development of hydrogen production solutions related to photovoltaic technology. Overall, P2G offers the ideal potential to convert the electricity produced by solar power plants that need to be downregulated, i.e. comprises a surplus in terms of scheduling, into green hydrogen, which is also suitable for long-term seasonal storage.

Witnessing the importance of energy efficiency and sustainability, there is a definite need for modular, standard-component-driven, vendor-independent energy management systems. A system with real-world scenarios capable of driving practical experiences and incorporating AI enhancements would serve as a base for Energy Community platforms that can include even small energy consumers and producers. A multi-year R&D pilot project was established to create a unique Energy Community model using the industrial environment at ZalaZONE, the Hungarian Vehicle Proving Ground in Zalaegerszeg. The main novelty of the project and the study is the unique setup of parallel R&D work from the academic and practitioner's view and the unique data per second of online, real-time data collection methodology and structure. The EMAK platform uses micro transactional data processing enabled to collect, aggregate, and analyse data every second, build more efficient consumption, and balance models with machine learning enhancements. The onsite research includes three buildings (five building parts) with 200 sensors, 5 data aggregators, energy meters, internal and external heat and humidity meters, and weather stations, measuring electricity consumption, heat, humidity, wind, sun radiation, and more environmental data. That network and the backbone software set measure, aggregate, display, and monitor 867 data points, transmitting 8,600,000 data points daily. Although the project lasts till 31^st December 2025, the work has already contributed to several key findings within the ecosystem.

As part of the energy transition, the building sector must be revolutionized to reach the goal of carbon neutrality since it is responsible for 3 Gt of CO2 emission worldwide every year. Energy storage capacities, which could help in the spread of renewables – are still at a very low level. Hydrogen is considered a solution for seasonal hydrogen storage, but only a few examples exist still worldwide to showcase the technology. The residential sector is more underrepresented in this manner. Therefore, the number of good practices should be higher to give examples to architects and engineers. In this paper, a design methodology is presented, which can help to identify and size the system components for autonomous (i.e., grid-independent) homes. An opportunity is given to estimate the cost of the whole complex electrical system. As the heat loss factor of buildings and the energy use of residents can be determined as part of the energy label certification, the sizing of the renewable energy equipment is an iterative process. For that, more grade system losses have to be taken into consideration. The result of this study is a numerical formula that gives the needed component properties. This offers stakeholders and real estate developers an easy tool to predesign their systems in the early stages of development.

The purpose of the paper is to analyse the typical research trends along the current challenges of the social, environmental and business aspects of sustainability and discuss the issues of geographically concentrated, park-like innovation ecosystems. At ZalaZONE Park as a consciously built innovation ecosystem, sustainability aspects are organically integrated into its development and into the operation approach, giving the empiric case for the research question. The ZalaZONE Energy Ecosystem Program connects the subject of sustainability with the innovation ecosystem on system level through innovative technologies and future-oriented environmental initiatives in various energy projects. In connection with this, it is also investigated is how new technologies support and ensure the long-term sustainability of the innovation ecosystem, and how the features of this relationship can be interpreted. Since ZalaZONE Park shows the characteristics of complex systems, the overall framework of the analysis is provided by the ecosystem model previously developed by the authors and further developed in the present analysis. Such a model contributes to each development step of the innovation ecosystem for sake of balanced and sustainability-oriented growth. Finally, an aggregated system model was presented including aspects of sustainability, with particular regard to the characteristics of complex systems.