The transition from a centralized to a decentralized energy infrastructure is one of the most discussed features of the future energy system. With the fast growth of renewable energy technologies, which can be integrated in the built environment and in contexts like small production centers, the development of distributed energy generation and storage systems closer to consumers is expected to play a significant role in driving the change. Within this context, the role of Energy Communities is emerging and is at the center of numerous studies. The Green Village in Delft is developing the 24/7 Energy Lab project, focusing on providing reliable, affordable and clean energy to a small-scale energy community by means of a system composed of solar panels for energy generation, batteries for electrical energy storage, and an hydrogen storage system consisting of electrolyzers, fuel cells and hydrogen tanks for seasonal energy storage. Previous research has highlighted how an off-grid configuration would result in inconveniently high costs for the community's users, if compared to the average cost of energy in The Netherlands. The aim of this thesis is to study the system in a grid-connected configuration, and in particular to find the optimal sizes of the components in order to achieve the best trade off between three conflicting objectives : minimizing total costs, maximizing self- sufficiency and maximizing reliability. After modeling the system's components and their mutual interactions, the optimization was carried out on MATLAB using a variant of the NSGA-II algorithm, which provides a Pareto Set of equally optimal solutions for the problem. The solutions were then ranked with a Technique for Order Preference based on Similarity to the Ideal Solution (TOPSIS), to assist the decision-making process. The simulations have determined that an installed capacity of 85.41 kWp (composed of 234 panels of 365 Wp each) results in the most effective choice for the solar energy generation, irrespective of the external conditions imposed. The optimal storage capacity, however, results significantly more influenced by factors such as grid imports limitations and price uncertainties. Under the conditions of limited imports from the grid, an optimal capacity of 75 kWh in the form of batteries was found. In general, the study confirms that the adoption of an hydrogen storage system is far from being convenient on a small scale residential level, regardless of the pricing conditions. The research has also posed an accent on the incremented costs incurred to reach full reliability of the system with low values of dependence from the grid, due to the high costs of the necessary storage equipment. Additionally, despite the best solutions found represent the optimal compromises balancing the conflicting objectives, reasonable solutions in terms of costs faced by the Community's users are usually not among the first choices of the ranking algorithm, mainly because they necessitate of at least 50% of the load to be supplied through grid imports.

With the phasing out of the Net Energy Metering (NEM) scheme, the energy market is shifting towards alternative solutions like independent energy storage, already successful in countries like Belgium and Germany. However, a single solution dominating the market is unlikely due to continuous innovation and the limitations of individual battery systems for prosumers and Distribution System Operators (DSOs). Community energy storage (CES) emerges as a promising alternative but lacks a defined business model, particularly for Dutch residential communities. This study delves into the implementation of centralized community energy storage systems to boost prosumer profitability and mitigate grid congestion in the Dutch solar residential market, in the wake of the NEM scheme phase-out. Community energy storage applications are identified, along with their respective potential business models. The optimal application, in terms of prosumer profitability and grid relief, is selected, and its associated business model is developed using the Morphological business model designed for energy communities. Furthermore, a practical approach for integration is proposed, based on regulatory and market constraints, to enhance the potential for large-scale emergence. This approach includes defining key roles and responsibilities of stakeholders within the community and the corresponding allocation of value. Subsequently, a technical system design topology is outlined for each defined community. This system design delves into engineering details to analyze the energy interaction possibilities between consumers and the grid, along with the corresponding financial implications. Accordingly, the CES application’s performance is simulated and evaluated both technically and financially. The potential is presented by simulating the interactions between the community, the grid, and the optimal battery system. This optimal interaction arises from an optimization problem formulated to provide the optimal battery size and its corresponding energy profiles that minimize the total community cost. Finally, an energy distribution mechanism is carried out through conditional decision making to evaluate the cost and profitability allocation among consumers within the community. The findings highlights the optimal application of CES, combining energy sharing with energy arbitrage, which significantly enhances the value of prosumers’ surplus PV energy, outperforming standard tariffs and avoiding grid feedback charges. This approach also provides consumers with access to more affordable shared community energy, while aiding DSOs in alleviating grid congestion and improving infrastructure capacity. The study suggests that the most effective strategy for widespread CES adoption involves collaboration between housing cooperatives and Energy Service Companies (ESCOs). Financially, this model entails community managers overseeing initial investments, complemented by household contributions via usagebased or fixed service fees. The business model’s success is influenced by the type of grid connection, with Behind-The-Meter (BTM) offering flexibility but lacking standardization, and Front-of-The-Meter (FTM) encountering challenges related to community energy taxation. Modelling the optimal operation for both BTM and FTM connections demonstrates a significant decrease of energy costs and contribution to grid relief, highlighting load smoothing and peak shaving as key benefits. The research concludes that centralized CES systems can substantially elevate prosumer profitability and reduce grid congestion, leading to considerable energy savings and enhanced grid performance in the Dutch solar residential market. To support the expansion of Community Energy Storage (CES) systems and energy communities, policymakers are advised to revise energy taxation policies and create frameworks aiding community grid formation, including simplifying regulations and offering incentives for residential initiatives. Researchers should adopt a multidisciplinary approach to explore regulatory, technical, economic, social, and environmental impacts on CES, focusing on regulatory effects, grid dynamics, cost-benefit models, community engagement, and environmental benefits. Industry stakeholders, such as Distribution System Operators, energy providers, Energy Service Companies, and housing cooperatives, should apply these research insights to develop and implement CES systems, fostering partnerships to address challenges and innovate in energy solutions, particularly in the evolving landscape post-Net Energy Metering, to enhance the role of community storage in sustainable energy systems.