Leuser Journal of Environmental Studies

Asymmetric Effects of Human Rights on Renewable Energy Consumption

2026-11-01T21:46:31+07:00

As the transition to renewable energy has become increasingly important for achieving environmental sustainability, understanding the institutional factors that influence renewable energy consumption (REC) is crucial. This study examines the relationship between human rights and REC using a panel dataset covering five world regions (Africa, Asia, Europe, North America, and South America) from 1990 to 2024. Employing an asymmetric panel ARDL and the Dumitrescu–Hurlin panel causality test, the results reveal a significant long-run nonlinear relationship in which improvements in human rights increase REC, while deteriorations in human rights reduce REC. Short-run effects vary across regions, reflecting differences in institutional and developmental conditions. The causality analysis indicates a bidirectional relationship between human rights and renewable energy consumption. These findings suggest that strengthening human rights institutions can promote renewable energy adoption, support environmental sustainability, and facilitate the transition toward a cleaner energy system.

Adaptive Solar–Electrolysis Architecture for Decentralized Energy Applications: A Preliminary Engineering Assessment

2026-11-01T21:46:29+07:00

The intermittency of renewable electricity presents a significant challenge for decentralized energy systems in which electrolysis is coupled to variable photovoltaic (PV) generation. This study develops a conceptual adaptive solar–electrolysis architecture for decentralized energy applications by integrating photovoltaic generation, adaptive energy management, battery buffering, wet-cell electrolysis, hydrogen-rich gas handling, safety provisions, and a potential household utilization pathway within a unified system framework. The study uses a conceptual engineering approach and does not include experimental or field measurements; it comprises functional requirement analysis, system architecture development, energy-flow formulation, adaptive operating logic, representative renewable-energy scenarios, functional comparison, and preliminary engineering assessment. Four study-specific conceptual indicators provide a structured basis for future quantitative evaluation: the Adaptive Energy Stability Index (AESI), Electrolysis Continuity Index (ECI), Renewable Adaptation Factor (RAF), and Integrated System Reliability Index (ISRI). These indicators are defined as conceptual assessment frameworks rather than established reliability standards or experimentally validated performance measures. The conceptual analysis formulates adaptive power coordination and finite battery buffering as a mechanism for managing short-term mismatches between photovoltaic generation and electrolysis demand. However, the proposed architecture cannot eliminate the effects of prolonged renewable-energy deficits because battery capacity is finite. Furthermore, when hydrogen and oxygen are not separately collected, the gas pathway considered in this study represents an H₂–O₂/HHO-type gas stream rather than experimentally verified pure hydrogen. Its actual composition, production rate, combustion behavior, and safety characteristics therefore require experimental characterization. The study establishes a preliminary system-level engineering framework for subsequent dynamic modelling, prototype development, quantitative performance assessment, safety validation, techno-economic analysis, and lifecycle environmental evaluation.

The Nexus between Hydropower Energy and Environmental Quality: Evidence from Granger Causality and Wavelet Coherence

2026-11-01T21:46:27+07:00

This study examines the relationship between hydropower energy and environmental quality in Indonesia over the period 1965–2024 using Granger causality and wavelet coherence approaches. Environmental quality is proxied by ecological footprint (EFP), greenhouse gas emissions (GHG), and carbon dioxide emissions (CO₂). The findings reveal that unidirectional causality runs from EFP and CO₂ to hydropower. In contrast, bidirectional causality is observed between hydropower and GHG. Furthermore, the wavelet coherence results show that these relationships are time-varying and frequency-dependent, broadly supporting the Granger causality findings while revealing how they evolve across different time horizons. Overall, the findings indicate that hydropower development in Indonesia is primarily driven by ecological footprint and carbon emissions, while its relationship with GHG emissions is characterized by mutual interaction, highlighting a differentiated and time-varying linkage across environmental indicators. This suggests that hydropower planning should be more closely aligned with environmental trends rather than treated as an independent driver of environmental improvement.

Context-Dependent Effects of PEG Grade on Lignocellulose Fractionation with Deep Eutectic Solvents

2026-11-01T21:46:26+07:00

This structured critical review evaluated how nominal polyethylene glycol (PEG) grade affects lignocellulose fractionation in deep eutectic solvents using an auditable corpus of 42 retained studies, including three within-study PEG-grade series. The eucalyptus studies showed modest PEG400 advantages for selected responses, whereas a sugarcane-bagasse screen gave the highest lignin removal (83.23%), glucose concentration, and glucose yield at PEG600, with lower cellulose retention than at PEG200/400; multivariable optimization subsequently selected PEG400. These contrasts show that nominal grade is a formulation variable rather than an isolated molecular-weight effect: equal PEG mass changes chain and terminal-hydroxyl concentrations, whereas a fixed choline chloride:PEG molar ratio also changes polymer mass and repeat-unit content. Candidate explanations are organized into four pathways—interaction-network modification; viscosity, diffusion, and steric trade-offs; phase behavior and partitioning; and lignin stabilization/carbohydrate protection. Current evidence supports formulation-dependent grade responses but not a universal grade ranking or numerical optimum. MW-REPORT is proposed to standardize grade characterization, normalization, mediator measurements, and product balances needed for reproducible formulation-specific selection.

Assessment of Arsenic and Mercury Contamination in Water and Sediments Around the Jaboi Sabang Geothermal Area Using ICP-OES

2026-11-01T21:46:24+07:00

The Jaboi Sabang Geothermal Area in Aceh, Indonesia, comprises four active craters that release geothermal fluids and gases into surrounding water sources used by local communities for daily activities. Despite the known toxicity of arsenic (As) and mercury (Hg) in geothermal environments, baseline data on their occurrence and distribution in local water and sediment remain limited. This study assessed As and Hg contamination in water and sediment samples using Inductively Coupled Plasma–Optical Emission Spectrometry (ICP-OES). Water samples were collected from hot springs, bathing pools, rivers, boreholes, dug wells, and treated water, while sediment samples were obtained from craters and stream beds. Method validation showed good linearity (R² > 0.99), with limits of detection (LoD) of 10.49 µg/L for As and 1.98 µg/L for Hg, and acceptable recovery values (70–125%). The highest As and Hg instrument responses in water were observed in hot-spring sample J1, at 11.268 and 6.861 µg/L, respectively. However, the As result for J1 was above the LoD but below the limit of quantification (LoQ), indicating detection without reliable quantification, while As in J2–J7 was below the LoD. For Hg, only J1 exceeded the LoQ, whereas J3 and J6 produced responses between the LoD and LoQ. The remaining samples were below the Hg LoD. Because the applicable Hg benchmark was lower than the method LoD, compliance could not be established for samples other than J1. These findings highlight the need for improved analytical sensitivity and continued monitoring to assess potential environmental and public health risks.