Varaždin County is rich in mineral resources, attracting considerable investor interest in opening new exploration areas and expanding existing exploitation fields. Since the economic value of mineral resources changes with market conditions, continuous professional assessment is required. Although the proposed methodological framework is broadly applicable to mineral resource management, this case study focuses on the exploitation of construction sand and gravel deposits in Varaždin County. In this way, it addresses the sustainability challenges characteristic of quarry operations rather than large-scale mining projects. The objective of this study was to develop and test a new method for quantifying sustainability indicators in the mineral resource management (spatial, resource-related, environmental, economic, and social sustainability—I_PREGS) and for calculating an aggregated composite index (AK_I) using a pilot project for construction sand and gravel. The research establishes a cause–effect relationship between quantified indicators (I_PREGS) and the newly established aggregated composite index (AK_I). Methodologically, the study applied multivariate analysis to questionnaire data, enabling the selection, weighting, and aggregation of indicators and the design of a conceptual framework for AK_I calculation. The resulting methodology provides an instrument for monitoring and improving sustainable mineral resource management, supporting the objectives of the circular economy. The findings highlight the potential of the AK_I to reduce systemic inefficiencies, guide policy development, and offer a transparent mechanism for assessing both implementation and effectiveness. This significantly improves the current state and strengthens the basis for evidence-based economic policy-making. The case study in Varaždin County further demonstrated that the AK_I not only reproduces administrative decisions with high consistency but also clarifies how applicants should proceed in cases of partial acceptance and how policymakers can interpret conflicting outcomes across different index variants.

In this paper, the authors elaborated on the conversion of excess electricity, generated from renewable energy sources by water electrolysis, into chemical energy and on its underground storing. Specifically, one of potential solutions...

Mining activity in the Republic of Croatia has its own legislation harmonized with EU regulations and market economy principles appropriate for Europe. Mineral raw materials are important for starting the economy of a particular country, and their use depends on the demand for energy, supplies, assumptions about the economic growth of certain regions and the state of the environment. The goal of the research is based on the research of strategic planning documents and studies that provide data on exploitation fields and exploration areas of mineral resources in the territory of the Republic of Croatia.The results of the research are based on previous knowledge about the exploration areas/exploitation fields and the data obtained from the research, which were determined on the basis of the resource base of mineral raw materials, i.e. mining-geological studies. In conclusion, the exploitation fields of mineral raw materials in the Republic of Croatia statistically do not cover large areas and it is possible to plan and produce them only in places where they exist, because the locations for exploration and exploitation depend on the geological composition of the area. Mining activity can disrupt the natural balance of the environment and space. In such situations, it is important to establish a balance between the market's (economy's) need for mineral raw materials and society's tendency to maximize environmental protection. The construction industry in the Republic of Croatia is an important factor that determines the need for the exploitation of technical construction stone, gravel and sand, as well as brick clay.

In the last decade, the Republic of Croatia has witnessed a continuous increase in municipal waste, but at the same time, there has been a steady rise in the rate of recovery and recycling. However, despite the positive trends, the set goals of waste management have still not been achieved dynamics of waste separation and processing. The City of Ludbreg, with almost 52 % of separately collected municipal waste, represents a successful model of sustainable and circular waste management, placing it among the only nine towns in the Republic of Croatia that have exceeded a 50 % rate of separately collected waste. This paper analyses the application of a circular waste management system in the City of Ludbreg and its role in achieving high recycling rates. Special emphasis is placed on the transformation of the local environment, including the elimination of illegal dumps and the creation of green spaces. The City of Ludbreg exemplifies how local communities can lead in circular economy practices by merging technological innovations with ecological awareness. Key success factors include education, local participation, and the integration of smart technologies in waste management. In conclusion, this research analyzes the challenges in separate waste collection and provides recommendations for further development and improvement of the waste management system at the local level, with the aim of achieving sustainable development goals. The result is the creation of an innovative and modern system that functionally integrates technology, infrastructure, and active participation of the local community, positioning the City of Ludbreg as an example of good and successful practice of a green and smart city.

Globalization and industrialization have significantly impacted the dynamics of waste generation, management, collection, and processing, resulting in increasing amounts of various types of waste and serious environmental challenges. This paper analyzes the treatment and recycling of construction waste through the legislative framework and presents key challenges in the implementation of green policies in the Republic of Croatia. The methodological framework is based on a qualitative analysis of normative acts at the national level. Through statistical analysis and a detailed review of the waste categorization process, including the origin, type, and properties of waste, as well as statistical data on the produced, collected, and utilized amounts of construction waste in 2022, an insight into the current state of the construction waste management sector is provided. The example of the company “Reciklaža Mišić” demonstrates how recovered construction waste can lose its waste status and be used as recycled aggregate if the assessment and verification of the constancy of performance are carried out according to the technical specification aligned with the legal regulations governing construction products. The research results indicate the need for further familiarization of the construction sector with the procedure for removing waste status so that recycled aggregates can become a construction product and ensure market placement of materials, thereby contributing to the circular economy and reducing environmental burden. In conclusion, the research shows that achieving sustainable construction waste management requires further strengthening of the economic sector, better integration of ecological principles, and active involvement of the local community in the waste management process.

The accelerating energy transition and growing geopolitical uncertainty have strengthened the strategic importance of hydrogen within future low-carbon energy systems. Green hydrogen is increasingly recognized as a key energy carrier supporting industrial decarbonization, renewable energy integration, long-term energy storage and energy security. However, existing hydrogen market assessment approaches remain fragmented and frequently focus on isolated technological, regulatory, or investment-related dimensions without sufficiently integrating the systemic interactions that shape hydrogen market maturity. To address this research gap, this study proposes the Integrated Green Hydrogen Market Development Index (IGHMDI), a multidimensional composite indicator framework designed to evaluate hydrogen market development through the integration of regulatory, technological, infrastructural, financial and strategic dimensions. This methodological framework is based on established principles of composite indicator construction, including indicator selection, normalization, weighting, and aggregation procedures adapted to the characteristics of emerging hydrogen markets. The proposed framework incorporates six principal dimensions: regulatory and policy development, technological readiness, infrastructure and market integration, investment and financial readiness, market demand and industrial adoption, and international cooperation and strategic positioning. An illustrative pilot application comparing Croatia and Germany is used to demonstrate the operational logic of the framework and its ability to distinguish between hydrogen markets at different stages of development. The illustrative assessment produced composite IGHMDI scores of 65.0 for Croatia and 91.7 for Germany, demonstrating the framework’s capability to distinguish hydrogen markets at different stages of structural development while providing a transparent basis for comparative assessment. The results indicate that hydrogen market development increasingly depends on the interaction between regulatory stability, infrastructure readiness, technological innovation, investment support mechanisms, market demand, and international coordination. The study also acknowledges that broader empirical validation, sensitivity analysis, and longitudinal application across a larger set of countries are required in future research. Overall, the IGHMDI framework contributes to the development of multidimensional hydrogen market assessment methodologies and provides a transparent analytical tool for comparative benchmarking, policy evaluation, infrastructure prioritization, and future hydrogen transition governance.