Secure and stable energy supply to cover the demand in all regions of EU is one of the main goals of regional, national and EU-wide energy policies. The globalisation of the electrical grid through introduction of RES (available locally) as well as the demand for a high flexibility of the electrical grid associated with new technologies that are purely depending on electricity (E-mobility, smart buildings/cities, digitalization etc.) requested economically and environmentally effective solutions for new level of power generations approaches (Industry 4.0). “The European Green Deal” is “… a new growth strategy that aims to transform the EU into a fair and prosperous society, with a modern, resource-efficient and competitive economy where there are no net emissions of greenhouse gases in 2050 and where economic growth is decoupled from resource use…“ (https://ec.europa.eu/info/sites/info/files/european-green-deal-communication_en.pdf). At EU level the progress of this policy can be realised only by cooperation of EU member states. The need for assessing the whole energy systems was already stated in the SET Plan: “Individual technologies development should be assessed for their integration and impact on the whole energy system (production, transmission, distribution and use of energy” and “… looking for life-cycle based solutions that reduce the overall need for energy by reducing waste and re-using and recycling materials” (Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions: Energy Technologies and Innovation. COM (2013) 253 final, Brussels, 2.5.2013). Integration of multidisciplinary scientific knowledge is necessary for the development of a system that considers all available technologies, complex links and interrelations between different factors and multi-criteria aspects. The concept of exergy as the main indicator of the quality of energy should be used more widely to evaluate energy conversion processes from the points of view of efficiency, cost and environmental impact.