Resources

32 pages, 7164 KiB

Open AccessArticle

Evaluating Policy Frameworks and Their Role in the Sustainable Growth of Distributed Photovoltaic Generation

by Annelys Machado Schetinger and André Frossard Pereira de Lucena

Resources 2025, 14(2), 28; https://doi.org/10.3390/resources14020028 - 3 Feb 2025

In response to the growing photovoltaic distributed generation market, this study investigates the evolution of energy policies and mechanisms driving the growth of photovoltaic distributed generation (DGPV). Analyzing the top ten countries in photovoltaic installations, it examines historical trends in capacity growth, installation [...] Read more.

In response to the growing photovoltaic distributed generation market, this study investigates the evolution of energy policies and mechanisms driving the growth of photovoltaic distributed generation (DGPV). Analyzing the top ten countries in photovoltaic installations, it examines historical trends in capacity growth, installation costs, and stakeholder engagement to evaluate policy effectiveness. Eight policy categories are identified as follows: direct financial incentives, energy market regulation, government management, production incentives, performance-based feed-in tariffs, renewable energy obligations, research and development initiatives, and agreements and commitments. The research results emphasize the crucial influence of government management policies, direct financial incentives, and energy market regulation on promoting the growth of DGPV. Political will and effective governance are identified as key drivers in advancing technology and market development. Policies reducing installation costs and encouraging investment support the transition of photovoltaic systems from early adoption to market maturity. Despite these advances, disparities in policy implementation highlight the need for adaptable frameworks tailored to local contexts. By leveraging solar energy, an abundant and universally accessible resource, nations can enhance energy equity through effective policies and accelerate the shift toward sustainable energy systems. This analysis offers valuable insights for policymakers seeking to promote DGPV as a central strategy in combating climate change. Full article

(This article belongs to the Topic Enabling Strategies and Policies Toward a Sustainable Environment, 2nd Edition)

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19 pages, 2112 KiB

Open AccessReview

Electrochemical Direct Lithium Extraction: A Review of Electrodialysis and Capacitive Deionization Technologies

by Jeongbeen Park, Juwon Lee, In-Tae Shim, Eunju Kim, Sook-Hyun Nam, Jae-Wuk Koo and Tae-Mun Hwang

Resources 2025, 14(2), 27; https://doi.org/10.3390/resources14020027 - 3 Feb 2025

Abstract

The rapid expansion of lithium-ion battery (LIB) markets for electric vehicles and renewable energy storage has exponentially increased lithium demand, driving research into sustainable extraction methods. Traditional lithium recovery from brine using evaporation ponds is resource intensive, consuming vast amounts of water and [...] Read more.

The rapid expansion of lithium-ion battery (LIB) markets for electric vehicles and renewable energy storage has exponentially increased lithium demand, driving research into sustainable extraction methods. Traditional lithium recovery from brine using evaporation ponds is resource intensive, consuming vast amounts of water and causing severe environmental issues. In response, Direct Lithium Extraction (DLE) technologies have emerged as more efficient, eco-friendly alternatives. This review explores two promising electrochemical DLE methods: Electrodialysis (ED) and Capacitive Deionization (CDI). ED employs ion-exchange membranes (IEMs), such as cation exchange membranes, to selectively transport lithium ions from sources like brine and seawater and achieves high recovery rates. IEMs utilize chemical and structural properties to enhance the selectivity of Li⁺ over competing ions like Mg²⁺ and Na⁺. However, ED faces challenges such as high energy consumption, membrane fouling, and reduced efficiency in ion-rich solutions. CDI uses electrostatic forces to adsorb lithium ions onto electrodes, offering low energy consumption and adaptability to varying lithium concentrations. Advanced variants, such as Membrane Capacitive Deionization (MCDI) and Flow Capacitive Deionization (FCDI), enhance ion selectivity and enable continuous operation. MCDI incorporates IEMs to reduce co-ion interference effects, while FCDI utilizes liquid electrodes to enhance scalability and operational flexibility. Advancements in electrode materials remain crucial to enhance selectivity and efficiency. Validating these methods at the pilot scale is crucial for assessing performance, scalability, and economic feasibility under real-world conditions. Future research should focus on reducing operational costs, developing more durable and selective electrodes, and creating integrated systems to enhance overall efficiency. By addressing these challenges, DLE technologies can provide sustainable solutions for lithium resource management, minimize environmental impact, and support a low-carbon future. Full article

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12 pages, 462 KiB

Open AccessArticle

Sustainable Production of Coffee Husk Pellets: Applying Circular Economy in Waste Management and Renewable Energy Production

by Angélica de Cassia Oliveira Carneiro, Antonio José Vinha Zanuncio, Amélia Guimarães Carvalho, Júlia Almeida Cunha Guimarães Jorge, Raquel Julia Cipriano dos Santos, Iara Fontes Demuner, Letícia Costa Peres, Shoraia Germani Winter, Vinícius Resende de Castro, Monique Branco-Vieira and Solange de Oliveira Araújo

Resources 2025, 14(2), 26; https://doi.org/10.3390/resources14020026 - 31 Jan 2025

Viewed by 535

Abstract

Improper waste disposal is one of the leading causes of environmental pollution, impacting soil, water, and air quality. In coffee plantations, each kilogram of beans produced generates an equal amount of husk, emphasizing the urgent need for sustainable practices to process this residual [...] Read more.

Improper waste disposal is one of the leading causes of environmental pollution, impacting soil, water, and air quality. In coffee plantations, each kilogram of beans produced generates an equal amount of husk, emphasizing the urgent need for sustainable practices to process this residual biomass into valued products. This study aimed to evaluate the potential of coffee husks for pellet production. Three coffee husk types were selected with distinct chemical compositions and granulometries: I (>5.3 mm), II (>2.6 mm and <5.3 mm), and III (<1.77 mm). The biomass was characterized for elemental, structural, and proximate composition. Pellets were produced with two knife heights (15 and 20 mm) and assessed for moisture content, density, length, and mechanical resistance, which were compared with the EN 14691-6 standard (DIN, 2012). Pelletizer productivity was also evaluated. Pellets from biomass III had an ash content of 12.09%, exceeding the <10% requirement. Other treatments met the ash content standard, category B. Pellets from biomass I (17.55%) and II (18.1%) at 15 mm length did not meet the <15% moisture content standard. The remaining pellets met category B standards. Only pellets from origin III (1.62%) met the nitrogen content requirement for international trade (<2%). Pelletizer productivity was higher with smaller granulometry biomass. Coffee husk has demonstrated its potential for pellet production, highlighting the valorization and use of this waste for clean energy generation, contributing to greenhouse gas emissions mitigation, and strengthening circular economy. Full article

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49 pages, 53915 KiB

Open AccessFeature PaperArticle

Assessing the Relationship Between Production and Land Transformation for Chilean Copper Mines Using Satellite and Operational Data

by Junbin Xiao, Tim T. Werner, Takeshi Komai and Kazuyo Matsubae

Resources 2025, 14(2), 25; https://doi.org/10.3390/resources14020025 - 30 Jan 2025

Viewed by 297

Abstract

Mining may cause devastating environmental impacts through large-scale land transformations. However, mining-induced land transformations are poorly understood relative to a mine’s productivity or life cycle. We integrated satellite imagery, geographic information systems (GISs), and mine site production data (ore, concentration, and waste) to [...] Read more.

Mining may cause devastating environmental impacts through large-scale land transformations. However, mining-induced land transformations are poorly understood relative to a mine’s productivity or life cycle. We integrated satellite imagery, geographic information systems (GISs), and mine site production data (ore, concentration, and waste) to conduct a detailed spatiotemporal analysis of 15 open-pit copper mines in Chile, distinguishing six types of features. Although the occupied area (9.90 to 149.61 km

^{2}

in 2020) and composition vary across mines, facilities for waste storage occupy the largest proportion (>50%) of the transformed land area, emphasizing the need for proper waste management. The analysis of land transformation factors (the transformed land area per unit production) showed high variation (0.006178 to 0.372798 m

^{2}

/kg-Cu) between mines over time. This reveals a significant problem in the historical practice of using averages from life cycle assessment (LCA) databases. This research reveals the significance of geospatial analyses in assessing mining-induced land transformation, and it provides geospatial data for land-related LCA. Mining companies are encouraged to disclose GIS information regarding land transformation to foster transparency and social responsibility, as well as to promote responsible and sustainable mining. Full article

33 pages, 23233 KiB

Open AccessFeature PaperArticle

Gravity and Magnetic Separation for Concentrating Critical Raw Materials from Granite Quarry Waste: A Case Study from Buddusò (Sardinia, Italy)

by Antonello Aquilano, Elena Marrocchino and Carmela Vaccaro

Resources 2025, 14(2), 24; https://doi.org/10.3390/resources14020024 - 29 Jan 2025

Viewed by 290

Abstract

The Critical Raw Materials Act (CRMA), enacted by the European Union (EU) in May 2024, represents a strategic framework that aims to address the growing demand for critical raw materials (CRMs) and reduce dependency on non-EU sources. The present study explores the potential [...] Read more.

The Critical Raw Materials Act (CRMA), enacted by the European Union (EU) in May 2024, represents a strategic framework that aims to address the growing demand for critical raw materials (CRMs) and reduce dependency on non-EU sources. The present study explores the potential of CRM recovery from granite extractive waste (EW) at a granite quarry in Buddusò (Sardinia, Italy). A significant quantity of granite EW, stored in piles within designated disposal areas at the quarry under study, is estimated in terms of mass and volume using GISs and digital elevation models (DEMs). Analysis performed using a scanning electron microscope attached to an energy-dispersive spectrometer (SEM-EDS) reveals the presence of allanite, a rare-earth-bearing mineral with substantial light rare-earth elements (LREEs), which can potentially be exploited for LREE recovery. A combined working process including gravitational and magnetic separations yields CRM-enriched fractions with concentrations of REEs, Sc, and Ga, reaching levels of potential economic interest for different industrial applications. Despite promising concentrations, limited knowledge of allanite processing represents significant challenges for CRM recovery from this waste. Therefore, the present study was conducted to assess the efficiency of these gravitational and magnetic separation methods in order to concentrate CRMs from granite EW. Economic evaluations, including potential market value estimates, suggest that CRM recovery from granite EW can be very profitable under optimized processing conditions. Expanding studies to other quarries in the region can provide valuable insights into the feasibility of establishing a recycling hub, offering a sustainable supply chain solution for CRMs within the EU’s strategic framework. Full article

(This article belongs to the Topic Sustainable Recycling and Reuse of Industrial By-Products or Waste from Geo-Resource Exploitation)

23 pages, 919 KiB

Open AccessArticle

Recycled Glass Bottles for Craft-Beer Packaging: How to Make Them Sustainable? An Environmental Impact Assessment from the Combined Accounting of Cullet Content and Transport Distance

by Magdalena Wojnarowska, Magdalena Muradin, Annarita Paiano and Carlo Ingrao

Resources 2025, 14(2), 23; https://doi.org/10.3390/resources14020023 - 29 Jan 2025

Viewed by 293

Abstract

Effective waste management plays a vital role in advancing sustainability goals across industries, with particular relevance to glass manufacturing—a sector that generates significant environmental challenges due to its resource-intensive production processes and high waste generation. The scale of production results in the accumulation [...] Read more.

Effective waste management plays a vital role in advancing sustainability goals across industries, with particular relevance to glass manufacturing—a sector that generates significant environmental challenges due to its resource-intensive production processes and high waste generation. The scale of production results in the accumulation of substantial amounts of waste glass, which, if not efficiently managed, contributes to environmental degradation. In this context, craft-beer production, which increasingly relies on glass bottles for packaging, presents unique challenges and opportunities for implementing sustainable practices. The sector faces trade-offs between increasing the use of recycled glass (cullet) and addressing the environmental impacts associated with transporting materials over long distances. The combination of centralized waste processing systems and long-distance transport adds economic and environmental costs, with transportation contributing up to 60–80% of overall waste management expenses. Addressing these issues requires an integrated approach that evaluates critical variables, such as cullet content and transport logistics, to identify solutions that balance economic and environmental efficiency. This study addresses the pressing issue of optimizing the recycling of glass bottles for craft-beer packaging by examining the combined influence of cullet content and transport distance on environmental sustainability. The objective was to assess the environmental impacts associated with varying levels of cullet content (0%, 57%, and 90%) and transport distances (25 to 250 km) using life cycle assessment (LCA) methodology aligned with ISO standards and the Product Environmental Footprint Category Rules (PEFCRs). The analysis demonstrated that increasing the proportion of recycled glass and reducing transport distances are key to improving environmental efficiency in bottle production. The most environmentally favorable scenario, S03 (90% cullet content), remains effective even at greater transport distances. In contrast, scenario S02 (57% cullet content) requires further distance reductions to maintain efficiency, particularly beyond 150 km. These findings highlight the importance of shorter supply chains and higher recycled material content as essential steps toward sustainable glass bottle production for the craft-beer industry. Full article

(This article belongs to the Special Issue Life Cycle Sustainability Analysis of Resource Recovery from Waste Management Systems in the Context of Circular Models of the Economy and the Bioeconomy)

18 pages, 4703 KiB

Open AccessArticle

A Novel Cogeneration System for the Simultaneous Production of Power and Cooling Operating with Geothermal Energy: A Case Study in La Primavera, Jalisco, México

by Alejandro Pacheco-Reyes, Juliana Saucedo-Velázquez, Geydy Luz Gutiérrez-Urueta and Wilfrido Rivera

Resources 2025, 14(2), 22; https://doi.org/10.3390/resources14020022 - 28 Jan 2025

Viewed by 326

Abstract

More efficient systems and renewable energies are determinants of reducing the negative impact on the environment. A novel cogeneration system is modeled for the simultaneous production of power and cooling driven by geothermal energy utilizing an ammonia–water mixture. The system can be used [...] Read more.

More efficient systems and renewable energies are determinants of reducing the negative impact on the environment. A novel cogeneration system is modeled for the simultaneous production of power and cooling driven by geothermal energy utilizing an ammonia–water mixture. The system can be used in rural communities by using renewable energies or in industries where waste heat is available. The system is a modification of a Goswami cycle in which a separator has been added to produce an extra amount of ammonia vapor to increase the cooling effect. Energy and exergy analyses are conducted as a function of the main operating temperatures. From the optimization, it is found that the maximum energy utilization factor is 0.54, and the exergy efficiency is 0.37, producing 81.45 kW of power and 1068 kW of cooling. A case study is also conducted for a rural community located in the estate of Jalisco, México. The proposed system is capable of preserving 3750 L of milk/day while simultaneously producing 12.53 kW of power when 230.6 kW of geothermal energy is supplied at 120 °C. Full article

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46 pages, 2401 KiB

Open AccessSystematic Review

Concrete Mix Design of Recycled Concrete Aggregate (RCA): Analysis of Review Papers, Characteristics, Research Trends, and Underexplored Topics

by Lapyote Prasittisopin, Wiput Tuvayanond, Thomas H.-K. Kang and Sakdirat Kaewunruen

Resources 2025, 14(2), 21; https://doi.org/10.3390/resources14020021 - 28 Jan 2025

Viewed by 578

Abstract

Recycled concrete aggregate (RCA) has been widely adopted in construction and emerged as a sustainable alternative to conventional natural aggregates in the construction industry. However, the study of holistic perspectives in recent literature is lacking. This review paper aims to provide a comprehensive [...] Read more.

Recycled concrete aggregate (RCA) has been widely adopted in construction and emerged as a sustainable alternative to conventional natural aggregates in the construction industry. However, the study of holistic perspectives in recent literature is lacking. This review paper aims to provide a comprehensive analysis of RCA, highlighting its properties, applications, and overall sustainability benefits to facilitate the comprehensive points of view of technology, ecology, and economics. This paper explores the manufacturing process of RCA, examines its mechanical and durability characteristics, and investigates its environmental impacts. Furthermore, it delves into the various applications of RCA, such as road construction materials, pavement bases, and concrete materials, considering their life cycle performance and economic considerations. This review reveals that there is a need for systemic data collection that could enable automated concrete mix design. The findings concerning various mix concrete designs suggest that increasing the 1% replacement level reduces the compressive strength by 0.1913% for coarse RCA and 0.2418% for fine RCA. The current critical research gaps are the durability of RCA concrete, feasibility analyses, and the implementation of treatment methods for RCA improvement. An effective life cycle assessment tool and digitalization technologies can be applied to enhance the circular economy, aligning with the United Nations’ sustainable development goals (UN-SDGs). The equivalent mortar volume method used to calculate the RCA concrete mix design, which can contain chemical additives, metakaolin, and fibers, needs further assessment. Full article

(This article belongs to the Topic Sustainable Recycling and Reuse of Industrial By-Products or Waste from Geo-Resource Exploitation)

34 pages, 7183 KiB

Open AccessArticle

Beyond Energy Access: How Renewable Energy Fosters Resilience in Island Communities

by Ravita D. Prasad, Devesh A. Chand, Semaan S. S. L. Lata and Rayash S. Kumar

Resources 2025, 14(2), 20; https://doi.org/10.3390/resources14020020 - 27 Jan 2025

Viewed by 974

Abstract

People, communities, and economies in small island developing states are extremely vulnerable to climate change, disasters, and other crises. Renewable energy can play an important part in building the resilience of these communities. Three case studies were conducted in Fiji (i.e., a grid-connected [...] Read more.

People, communities, and economies in small island developing states are extremely vulnerable to climate change, disasters, and other crises. Renewable energy can play an important part in building the resilience of these communities. Three case studies were conducted in Fiji (i.e., a grid-connected secondary school with roof-top solar PV and biogas, an off-grid community with solar home systems, and a farm that uses solar PV for irrigation) to demonstrate how renewable energy initiatives build community resilience. This study used the community resilience framework, RETScreen tool, information gathered from key informants’ interviews, and secondary data sources to conduct qualitative and quantitative analyses. It found that seven community assets, i.e., human, social, cultural, financial, natural, built, and political assets, are enhanced, leading to an increase in absorptive, adaptive, and transformative capacities for these communities. Furthermore, current research shows that human capital is one of the key instruments in the adoption of new innovative technologies. The results from this study can be used by decisionmakers to promote and implement similar technologies in communities, which not only provide clean electricity and clean cooking energy for climate change mitigation but also build community resilience. Full article

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21 pages, 1367 KiB

Open AccessFeature PaperArticle

Competitive Potential of Stable Biomass in Poland Compared to the European Union in the Aspect of Sustainability

by Rafał Wyszomierski, Piotr Bórawski, Lisa Holden, Aneta Bełdycka-Bórawska, Tomasz Rokicki and Andrzej Parzonko

Resources 2025, 14(2), 19; https://doi.org/10.3390/resources14020019 - 21 Jan 2025

Viewed by 591

Abstract

Biomass is the primary source of renewable energy in Poland. Its share in renewable energy production in Poland has decreased in recent years, but it still maintains a nearly 70% share. Poland has extensive forest and straw resources, such as pellets, which can [...] Read more.

Biomass is the primary source of renewable energy in Poland. Its share in renewable energy production in Poland has decreased in recent years, but it still maintains a nearly 70% share. Poland has extensive forest and straw resources, such as pellets, which can be used for stable biomass production. The main objective of this research was to understand the potential of plant biomass production for energy purposes in Poland and other European Union (EU) countries in terms of sustainable development. The period of analysis covered 2000–2022. Secondary data from Statistical Poland and Eurostat were used. The primary research method was the Augmented Dickey–Fuller (ADF) test, which aimed to check the stationarity of stable biomass. Moreover, we calculated the Vector Auto-Regressive (VAR) model, which was used to develop the forecast. The indigenous production of solid biomass in 2022 decreased to 363,195 TJ, while in 2018, it was 384,914 TJ. Our prognosis confirms that biomass will increase. The prognosis based on the VAR model shows an increase from 365,395 TJ in 2023 to 379,795 (TJ) in 2032. Such countries as France, Germany, Italy, Spain, Sweden, and Finland have a bigger potential for solid biomass production from forests because of their higher area. As a result, Poland’s biomass production competitiveness is varied when compared to other EU nations; it is lower for nations with a large forest share and greater for those with a low forest cover. The two main benefits of producing solid biomass are its easy storage and carbon dioxide (CO₂) neutrality. The main advantage is that solid biomass preserves biodiversity, maintains soil fertility, and improves soil quality while lowering greenhouse gas emissions and environmental pollutants. The ability to leave added value locally and generate new jobs, particularly in troubled areas, is the largest social advantage of sustained biomass production. Full article

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