12 Discussion
The aim of this work was to address the existing gap in the literature regarding the scalability of energy planning. To achieve this, we employed a methodology that involved creating different scenarios to explore the research sub-questions and ultimately provide insights into the main research question. Although the research question and sub-questions were on elements identified in the literature, we must acknowledge that this study did not succeed in filling the identified gap. Consequently, we regretfully conclude that it is not possible to provide a definitive answer to the research question “What are the benefits of pooling of energy demand and equipment for a district?”
Despite not being able to fully address the main research question, the conducted analyses have led to valuable insights. In light of these findings, we propose a comprehensive summary of the analyses conducted with respect to each intermediate research questions and the corresponding results. The purpose of this discussion is therefore to provide an overview of the analysis in order to allow us to identify the limitations of the work and thus to explore potential future directions for research in the field of energy planning, particularly regarding the pooling of energy demand and equipment.
What are the distinctions and advantages of optimising energy systems at the district level compared to individual building scale? Our analyses failed to identify any differences between the two methods of opitimisation, namely the building-scale and the district-sclae because of the electricity retail and feed-in tariffs. The initial motivation behind this question stemmed from the growing interest in energy communities and the underlying idea that operating as a community rather than as an individual building would allow offsets between production and consumption to improve the system. Regrettably, due to highly favorable electricity feed-in prices, no optimisation measures, be it through mutualisation or storage, are required. Consequently, the installation of solar panels on roofs leads to the optimal solution.
Does the penetration of renewable energy face limitations imposed by grid constraints? Imposing constraints of 2x and 3x the maximum domestic electricity power on the grid contributes to a more realistic scenario, as an unconstrained grid does not exist. With these constraints, TOTEX increases because the power injected into the grid becomes limited, leading to a decrease in sales. By comparing scenarios with constraints, where the same number of PV panels is used as in the unconstrained scenario, a significant amount of curtailment is observed. This curtailment indicates that maintaining the same number of PV panels is no longer cost-effective, as not all the energy produced can be utilized. Consequently, it becomes logical to reduce the number of PV panels, highlighting the influence of constraints on the penetration of renewable energies. Our analyses also showed that the specific values imposed on the constraints (2x maximum power and 3x maximum power) yield similar outcomes, with minimal differences observed between the two scenarios.
Are storage technologies necessary to improve self-consumption or self-sufficiency in energy systems? The question of storage was motivated by the need to integrate it into the concept of the energy community, not only to take into account the possible balance between production and consumption, but also to store the surplus energy produced in order to improve the overall system. Our examination of the Vessy district demonstrated that incorporating storage leads to improvements in self-consumption and self-sufficiency. We only analysed the Vessy district because we adopted the assumption that people in the district use electric cars. This assumption is more difficult to make when looking at the Jonction and Florissant districts, as they are not residential areas. Our analyses consistently validate the significance of storage, with a clear reduction in TOTEX when it is taken into account.
Can a district effectively achieve carbon neutrality considering its energy demands and available resources? The analyses conducted after the different scenarios, which plots are presented in appendix, reveal the possibility of achieving carbon neutrality depending on the composition of the district. Our findings indicate that carbon neutrality is attainable for Vessy and Jonction, whereas it is not feasible for Florissant. These results are consistent with the observations made during the analysis of constraints. Our analysis shows that carbon neutrality depends on the ratio between the maximum power of domestic electricity and the solar surface area. A lower ratio implies a reduced energy requirement per square meter, which is advantageous. However, a higher ratio necessitates a greater energy import, consequently impacting carbon neutrality negatively, which is the case for Florissant.
The various analyses carried out have contributed to a better understanding of some of our research sub-questions without, however, providing an answer to the main research question. Indeed, the first research sub-question remains unanswered, which implies that it is difficult to answer the main question. This situation highlights the limitations of our work, while allowing us to reflect on the future directions that the analyses should take.