# A Heuristic Approach to the Decision-Making Process of Energy Prosumers in a Circular Economy
## 1 Introduction  
A key principle of the circular economy (CE) is that energy is powered via renewable sources [1], leading to significant reductions in fossil-fuel consumption [2, 3] and greenhouse gas (GHG) emissions [4]. Additionally, some authors argued that the CE also shifts toward the use of waste-derived resources in value chains [5], while companies undertaking activities related to the CE introduced the consumption of renewables [6, 7]. [PERSON] et al. (2015) indicated that strategies targeting the CE are shifting from fossil fuel to renewable energy sources and translating efficiency gains into a reduction in the overall level of resource consumption [2]. In the same vein, a shift toward a more efficient and distributed energy generation model based on renewables, as is the case for self-consumption, is appearing [8]. Self-consumption deployment increases energy self-sufficiency within an energy-transition period toward a new, more sustainable, and circular model, and it helps maximize the consumption of locally generated electricity. Thus, self-consumption can increase retail competition and support market transformation, promoting the entry of suppliers capable of offering new services in a circular business model, in response to more rooted levels of public and private green purchases [9]. In a circular model, renewable self-consumption helps achieve two objectives in parallel. Firstly, it very concretely empowers consumers while facilitating a bottom-up deployment of renewables. More importantly, the consumers' involvement in the energy market contributes to the achievement of binding national renewable targets by attracting private capital from actors (i.e., consumers) who havelower expectations in terms of rate of return compared to pure financial investors [10]. In addition, it has to be taken into account that the market for renewable technologies relies on a variety of materials that will evolve in the future depending on their deployment rates and the technology mix, such that the CE has to be considered for recycling and material procurement [11]. In summary, evolution toward a CE depends on structural changes in the management of energy and material flows, especially in a new configuration of economic interactions. Solving technical problems does not guarantee the success of this circular scheme, and economic and social challenges must also be addressed. More recent circularity concepts have shifted the perspective to include consumers that, instead of matching their needs to the product offerings available, would cocreate or coproduce the products and services they actually need; thus, the importance of culture, education, and awareness in achieving circularity has been highlighted [12]. In this scenario, the aim of this study was to explore insights into the decision-making process of energy prosumers to enhance the understanding of self-consumption deployment and to support effective policymaking. This study contributes to the state of the art by defining and classifying determinants of the prosumers' decision-making process and their relevance using a heuristic approach. In particular, a Spanish case study is analyzed to ascertain which factors play a significant role in photovoltaic (PV) self-consumption adoption; these factors are subsequently graded on the basis of the results of a semi-structured interview among a sample of prosumers. We analyze the results obtained through an explorative study on decision-making in self-consumption facilities, using data collected through semi-structural interviews of prosumers within facilities installed by a Spanish company (please see [[https://www.fenieenergia.es/](https://www.fenieenergia.es/)]([https://www.fenieenergia.es/](https://www.fenieenergia.es/)) (accessed in August 2020)). This article is organized as follows: After the introduction, Section 2 provides the theoretical approach to set the basis for the evaluation of the case study, which is described in Section 3, along with an analysis of the results and a discussion.