## 2 State of the Art
New processes and methodologies are needed in order to enable SET integration decisions to be made effectively and sustainably in the face of the aforementioned ambiguity and an acute urge to act [23; 24; 25; 26]. This paper presents a novel methodology that supports decision makers in the context of grid expansion to systematically incorporate citizens' opinions as well as discrepancies in their opinions into their decisions. Participation deals with the process of involving the public and stakeholders in making decisions that affect themselves, whether passively via consultation, or actively via two-way engagement [23]. There are different types of engagement, such as (1) top-down one-way communication and/or consultation, where engagement is initiated by an agency with decision-making power for communicating decisions, or for consulting with stakeholders/the public while retaining decision-making power; (2) top-down deliberation and/or coproduction, where stakeholders/the public are engaged in two-way discussions prior to making a decision--coproductive approaches would involve jointly developing a decision and ways to implement it, where the organization with decision-making power would be responsible for the implementation; (3) bottom-up one-way communication and/or consultation, where engagement is initiated and led by stakeholders/the public to persuade decision-making bodies to allow engagement/consultation, and to influence decision makers or overturn decisions; and (4) bottom-up deliberation and/or coproduction, where engagement is initiated and led by stakeholders/the public, who engage in two-way discussions on the decision; decisions are made and implemented by a group of stakeholders/the public--possibly in a coproductive manner [27]. Appropriate methods of engagement depend on the purpose and context in which engagement is needed, where success can be seen as achieving beneficial outcomes or building trust in decision-making processes. In our context, engagement means actively consulting with the public on various SET implementations to achieve beneficial and widely accepted solutions. With regard to concrete means of participation, citizen e-participation is a form of co-production with the potential to--for example--enhance government service quality [28]. In general, digital citizen participation is of great importance for the development of smart sustainable cities [29], where citizens and communities need to be proactively engaged--e.g., using digital tools and smart technologies--and diverse audiences should be considered to ensure equity and social justice [25]. Citizen participation particularly plays a key role in the energy transition and in successful energy project planning and implementation [24; 30], and must be further considered in strategic planning and, at the regional/community level, participation should be supported and considered in the early phases [31]. Furthermore, the governance framework enabling communities to participate needs to be enhanced [26]. Our research promotes public participation in the energy transition, and proposes several structured double surveys with a fixed stakeholder group that enable a structured unveiling and handling of discrepancies in the context of sustainable decision making. The evident conflict between economic and environmental goals was the main driver that led energy planners to use MCDA methods in the early 1980s [32]. Beginning with questions about grid design with respect to a single energy carrier, the importance of using MCDA methods for planning issues has increased with the growth in the complexity of energy systems. This is due in part to the use of multiple energy sources and the proliferation of distributed generation and conversion thereof [33; 34].