## 2 Detailed Analysis of the Literature
### Prosumer Communities
#### 2.1.3 Prosumer Community/Coalition Formation  
A group of prosumers collectively selling energy to the grid is more efficient and reliable in providing sustainable energy supply compared to a prosumer acting as an individual entity [4]. Aside from being too small to compete with traditional energy generators, individual prosumer's energy supply is unpredictable due to dependency on climatic conditions [10]. These challenges in efficiency and reliability led to the emergence of PCGs [11], also referred to as EPCs [17], ICESs [18; 19; 20; 21], or CECs [22]. In a PCG, the prosumers interact with other prosumers and smart grid via a community gateway. A community gateway is an intelligent component connecting the grid to smart devices within the community [11]. Optimal prosumer communities offer a range of socio-economic benefits namely enhancing prosumers bargaining power, achieving higher sustainability, facilitating efficient energy transfer, reducing energy transfer cost, reducing energy loss, and promoting active involvement of the energy user into the supply chain [11]. However, the challenge lies in grouping prosumers together to achieve long-term sustainability of the PCG. Several studies addressed this challenge. One such study proposed an algorithm that outputs coalitions of prosumers designed for aggregators who seek to maximize their offer of energy production while minimizing the risk of financial penalty if production falls below contracted amount [45]. Real weather data of a given territory is used to simulate realistic prosumer behaviors. Based on the geographical correlation structure, the algorithm forms coalitions with both high productivity and low variability of energy production. Findings show that the generated coalitions provide more energy to the grid with lower variability, hence use less storage and waste less energy compared to unstable coalitions. The formed coalitions are also more resilient to random prosumer failures [45]. ICESs are designed to deal with the rapidly changing energy landscape [18; 19]. It is a socio-technical system consisting of technologies and social systems. The technologies manage the commodities flow from generation to storage and distribution. The social system made up of different actors (aggregators, energy suppliers, prosumers, system operators) handles the operations taking into account the economic efficiency, environmental effects and consumer options [19]. ICES primarily aims to meet the energy requirement of a local community through effective synergies among multiple energy providers [18]. It redesigns local energy systems by integratingdistributed energy resources (DERs) and engaging local communities, which ensures self-provisioning of energy. There are several ways to integrate energy systems (such as virtual power plants or VPPs, community grids, energy hubs, PCGs, and community energy systems) and various issues and trends influencing the development of ICESs [18]. Some of these issues are intermittent local energy generation [46], local balancing of supply and demand [47], community engagement [4; 10; 12], split-incentive problem [48], trust, motivation and continuity [49]. Another form of PCG is CECs that are distributed and decentralized [22]. An exploratory study of CEC discusses its different forms such as peer-to-peer (P2P), VPPs, and microgrids. It also talks about the transition and evolution of communities and grids [22]. The analysis reveals that \"low-carbon transition pathways will be varied, driven by social, technological and organizational contexts, and shaped by institutional change processes, and interaction with the existing regime and incumbent actors [22].\" The study reported a SWOT (strengths/weaknesses/opportunities/threats) analysis on Current Utility Mode, Centralized CEC, Distributed CEC and, Decentralized CEC.