The objective is to analyse the effect of new energy technologies on markets by modelling their integration into energy systems at different scales: local, regional and national. This analysis is focused on the challenges arising from the incorporation of emerging technologies, such as renewable energies, green hydrogen and smart grids, which seek to improve the efficiency and security of energy supply. To address these challenges, optimisation and simulation models are developed to facilitate energy planning, considering aspects such as energy system design, budget allocation and cost estimation of energy projects. These models are also used to explore and evaluate the financial and environmental impact of implementing emerging technologies in an energy system.