Environmental protection and sustainable development cause a qualitative shift towards cleaner technologies in the field of electrical power. Countries with fossil fuel-based electricity generation have a questionable energy future regarding the independence and security of their end-users' supply. Therefore, it is necessary to explore all possible options for future development, taking into account the synergistic potential of other energy sources in electricity deficit compensation. That need will arise after the shutdown of fossil fuel power plants. It is necessary to mutually synchronize the development and application of different energy sources. For example, the large share of renewable energy sources with highly variable generation, without the presence of significant energy storage capacities or other sources that could compensate for these rapid power fluctuations, causes problems in energy balancing and disrupts power system flexibility and stability. Among the supporting pillars of a secure and decarbonised power system, special attention will be paid to the possible role and contribution of consumers; increasing their energy efficiency, using the heat capacity of buildings, demand response and direct demand side management.