The energy system is undergoing a major transformation where the dependence on fossil fuels needs to be replaced with solely sources of renewable energy. The increased share of renewable intermittent electricity production, together with urbanization, electrification, and digitalization, creates challenges for the operation security in the electricity system. Moving from a centralized to a decentralized electricity system is considered a solution to face the challenges of the energy system. In EU's Clean Energy Package, the concept of energy communities emerged to achieve decentralized energy systems. Energy communities lack a clear definition, but overall, it can be explained as a collaboration between local stakeholders who produce, consume, and manage their own energy systems to create economic, environmental, and social benefits.  In this study, the definition of energy communities is broad and is defined as a local area where electricity is shared between at least two buildings through a direct current grid or virtually through smart meters. As the concept is underdeveloped and lacks a clear enabling framework, the purpose of this study is to investigate how energy communities are developing in Sweden today. The focus of the study is to examine the roles of actors in the development of energy communities and the driving forces they have, the challenges and associated solutions that actors have encountered, and the system benefits that energy communities can contribute to.  The results show that roles in an energy community are general and can be taken by different types of actors depending on local conditions, interests and knowledge. Despite the variation of roles, the roles of an aggregator, knowledge bank, and a project manager are essential for the development of energy communities. The drivers for developing energy communities are closely linked to the project manager and their internal goals within the organization. Drivers are largely dependent on the roles of the actors within the energy community, where for example electricity grid companies’ focus on creating a system perspective of the energy community's position and role in the energy system. In summary, the results show that the biggest drivers are to reduce electricity grid costs and to balance load of the electricity grid.  Several different types of challenges are mentioned by the interviewees, where the challenges can be divided into technical, economic, social, and legislative. The most debated challenge in literature and in the interviews are legislative challenges, where legislation is considered unclear by most interviewees. Important solutions that are mentioned are to create consensus and cooperation between actors and to follow the development to understand the opportunities and consequences of energy communities.  The system benefits that energy communities can create for the electricity system are, based on the literature and on the results from the survey and interview study, difficult to define. Several projects are still under development, which means that system benefits have not yet been documented and therefore rely heavily on thoughts about future development. Common system benefits mentioned in this study are that energy communities can relieve the main electricity grid by a decrease in power outtake and providing flexibility services as well as increasing the total share of renewable energy sources.

During the last years the number of installed PV-modules have increased significantly. As a result, the self-consumption of the solar electricity has become more important. One way to increase the self-consumption is to install an energy storage, for instance a battery. Another way is to introduce a physical energy community. An energy community is a way to share energy, in this case local produced renewable energy from the PV-panels, between buildings in a local electrical-grid.  The aim of this project is to investigate how the self-consumption change when an energy community is introduced and explore differences depending on the heating system of the building. This energy community includes seven buildings, two buildings with district heating and five buildings with heat pumps. An economic analysis of the economic benefits of energy communities is also included. The project is conducted as a case study of a new block that is under construction in Örebro. A building simulation have been performed in IDA ICE 4.8 SP2. This includes simulations of energy consumption and energy production from PV-modules. The battery model is done in Matlab and used to simulate different battery sizes. The self-consumption increases when an energy community is established for all the individual buildings no matter of the heating method. For buildings with heat pump, the self-consumption was higher than it was for the buildings with distric-heating. The district heated building with the lowest self-consumption as an individual building increased its self-consumption from 66.7% to 72.5% when joining an energy community with only one other building. For building with heatpump the lowest self-consumption was 82.5% and in an energy community the self-consumption increased to 92.6% From an economic aspect it is a good idea to establish an energy community regardless of size and type of heating method that is used in the buildings. For all communities the repayment period for the PV-modules is shorter for the community than it is for the individual buildings. However, to install a battery for the community is not profitable if you only load the battery when there is an overproduction from the PV-modules compared to the need from the load.

Planer finns till att bygga ett mikronät på Hemsön, i Härnösand. Denna studie syftar till att utreda möjligheter till detta och om möjligt identifiera var kostnadsbesparingar kan göras inför byggnationen och implementeringen av denna energigemenskap. Mikronätet kommer innefatta 18 tomter varvid sommarstugor förväntas byggas och enligt kontrakt även ska inkludera en produktionsanläggning för egenproducerad el, vilka förväntas bli solceller. En utredning har även gjorts för att finna svar på om energilagring via elfordon kan utnyttjas i stället för ett batterilager. Studien har funnit att denna typ av energilagring har potential att eliminera behovet av inköpt el under sommarmånader då solel produceras. Vidare har studien tydliggjort att implementering av detta mikronät ej tillåter en högre total produktion än 44,1 kW, vilket är betydligt lägre än först var väntat. Studiens resultat visar på att kabelskåpets impedans bör reduceras om högre produktion är önskat. Detta kräver vidare dialog med elnätsföretaget och en fortsatt utredning för detta är rekommenderat i framtiden. / Plans have arisen to build a micro grid in Hemsön, Härnösand. The purpose of this study is to evaluate possibilities for solutions and identify ways to save on costs during the building and implementation of the micro grid. The grid will contain 18 building plots where vacation homes may be built, which by contract shall include energy production assumingly solar panels. An investigation has also been conducted regarding if electric vehicles can be used for energy storage instead of batteries. During the study it has been found that energy storage through electric vehicles has the potential to eliminate the need to buy electricity during the summer months when solar power is produced. Furthermore, the study has shown that the maximum total production of solar power for the micro grid is 44,1 kW which is less than first expected. It has been found that the impedance needs to be reduced if a higher production is wanted. To resolute this, a dialogue needs to be held with the power supplier which is recommended going forward.

In an increasingly interconnected, and electricity-reliant world, households are asked to build up their resilience to crises. Local, distributed electricity production within a microgrid with capability to operate disconnected from the larger grid has been shown to be an effective tool for increasing power system resilience in the past. The energy production of local renewable sources is, however, not sufficient in meeting normal household energy demand. This thesis explores whether the forming of communities can be utilised to reduce energy demand and as a result, increase the resiliency of both the community and urban environments. The analysis of household energy use and the subsequently developed toolbox provide insights into energy use both under normal societal function and during a crisis. Through living and cooking together as a community, significant energy-efficiency gains were possible, exceeding those reasonably achieved within each individual household. Community was further determined to be important in the planning and development of more resilient combinations of renewable energy, going beyond solar power. When implemented in theoretical scenarios, energy communities at a building and block level could provide sufficient energy for the households’ most immediate needs without major sacrifices of wellness. The scheme proposed is argued to require not only monetary investments, but also larger societal shifts. Producing sufficient quantities of electricity within urban environments will mean a large change in how cities are experienced. Public understanding and acceptance for such a change is likely to be necessary. Through the implementation, the role of the municipality would go from action-taking to mostly laying the groundwork for the formation of communities, as well as advising these as they achieve higher household resilience. Most critically, however, there is a need for the broader population to embrace working together in communities.