This work investigates the viability of fuel cells (FC) used as combined heat and power systems (CHPs) in commercial buildings with a specific focus on supermarkets. Up-to-date technical data from a fuel cell manufacturing company was obtained and applied to evaluate their viability in an existing food-retail building. A detailed optimisation model described in previous works enhancing distributed energy system management is expanded upon to optimise the techno-economic performance of FC-CHP systems. The optimisations employ comprehensive techno-economic datasets that reflect current market trends. Outputs highlight the key factors influencing the economics of FC -CHP projects. Furthermore, a comparative analysis against a competing internal combustion engine (ICE) CHP system is performed to grasp the trade-offs of each system. Results indicate that FCs are becoming financially competitive although ICEs are still a more attractive option. For supermarkets, the payback period for installing a FC system is 4.7-5.9 years vs. 4.0-5.6 years for ICEs when policies are considered. If incentives are removed, FC-CHP systems have paybacks between 6-10 years vs. 5-8.5 years for ICE-based systems. A sensitivity analysis under different market and policy scenarios is performed, offering insights into the performance gap fuel cells face before becoming more competitive.

Monsieur le Professeur Michel GAUTHIER pour avoir accepté la direction de cette thèse et m 'avoir fait bénéficier, avec une attentive indulgence et une longue patience, de ses conseils et de son savoir. Les longues discussions que nous avons eues m Ont été une source d'inspiration.

Discussions around the issue of maternity leave are timeless and although there has been a great improvement regarding the rights of working mothers, the total policy upgrade remains a challenge. This research focuses on the efforts that have been made at EU level in order for its member states to coordinate their maternity leave policies and establish favorable terms. Furthermore, the impact that maternity leave has on employment rates, gender equality, family roles and generally, on many aspects of people's lives is highlighted. Last but not least, it should not be neglected that the mistreatment of working women affects the whole of society and not only pregnant women, thus for this reason, this situation should be dealt with through pioneering and revolutionary changes.