The support of actions aimed at reducing levels of pollution emissions into the environment requires popularization of good practices, including those involving solutions in the field of the circular economy. These actions are particularly important in sectors of the economy characterized by a high share of total emissions, as their modernization through economies of scale translates into greater environmental benefits. An example of such a sector is the energy sector. The aim of this paper is to identify and characterize selected processes within the activities of the energy sector, where a circular economy approach can be applied, and to assess the implemented solutions. This analysis was carried out using the largest entity in the Polish power sector as a case study. Process analysis was conducted using the value stream mapping method. The identified circular solutions in the process and product areas constitute an important contribution to promoting the activation of economic entities in actions aimed at improving the state of the environment.

The high consumption of raw materials and the generation of construction and demolition waste (CDW) represent significant sustainability challenges. The circular economy (CE) offers a promising pathway but requires effective legislation. Although considerable attention has been devoted to the technical and economic aspects of CE, comparative analyses of national regulatory frameworks remain scarce. This study addresses this gap by conducting a comparative analysis of the regulatory environments of nine countries: Cyprus, Estonia, Greece, Latvia, Poland, Romania, Slovenia, Switzerland, and Türkiye. With a retrieval-augmented generation (RAG) architecture based on a large language model (LLM), national and regional legal texts were analysed and fact-checked by experts. The results reveal substantial differences in regulatory maturity, enforcement mechanisms, and data platforms, resulting in the identification of three country clusters. The findings indicate that effective CDW management depends on legislative harmonisation, institutional capacity, data openness, and economic incentives. In addition, the study suggests that LLMs can serve as powerful instruments for comparative legal analysis in multilingual sustainability research.