Energy Science & Engineering最新文献

Indonesia's considerable geothermal resources present tremendous potential for energy production, yet restricted investor interest hampers development. This study evaluates the economic viability of a proposed 330 MW geothermal power plant in Gunung Kembar to encourage investment and facilitate Indonesia's 2060 Nationally Determined Contributions (NDC). Four scenarios were modeled using RETScreen, each differing in carbon credit pricing and project duration. Scenario I implement a carbon credit price of $2 per metric ton of CO₂ over a 25-year period, resulting in a Net Present Value (NPV) of $22 million and a Levelized Cost of Electricity (LCOE) of 0.091 USD/kWh. Scenario II elevates the credit price to $18, resulting in an NPV of $23.5 million. In Scenario III, prolonging the project lifespan to 30 years yielded a NPV of $30.6 million and a LCOE of 0.088 USD/kWh. Scenario IV, featuring a credit price of $50 and a term of 30 years, attained the highest NPV at $67.9 million and an LCOE of 0.088 USD/kWh. Scenario IV demonstrates the most economic potential, indicating that elevated carbon price may augment project profitability and stimulate renewable investment in Indonesia.

Although the conversion of end-of-lifetime fractured hydrocarbon wells to geothermal wells has gained a strong momentum in research, it is necessary to perform thorough technical assessments of well conversion before pilot testing. The objective of the study was to perform such an assessment on converting fractured horizontal hydrocarbon wells to geothermal wells based on heat transfer efficiency analysis. A mathematical model was developed in this study to simulate the transient heat transfer from shale formations to hydraulic fractures. Sensitivity analysis was performed with the model to identify key factors affecting the heat transfer processes. In all cases studied, the temperature at the exit of the fracture is significantly higher than that at the entrance of the fracture in the first month, indicating high efficiency of heat transfer. Result of this study suggests that converting fractured-horizontal hydrocarbon wells to geothermal wells is a viable process to extend the lifetime of old wells in oil and gas fields with high-geothermal gradients. However, well rotation is needed to maintain the energy productivity of reservoir.

Real-time analytics for production parameters monitoring trends for dissolved-gas allocation in petroleum reservoirs using satellite remote sensing has emerged as a precise and cost-effective tool for quantifying gas flaring across hydrocarbon production sites, enabling continuous monitoring of greenhouse gas emissions and supporting strategies to mitigate air pollution, climate change, and environmental degradation. Beyond regulatory compliance and policy development, satellite observations provide unique advantages in remote or inaccessible areas, surpassing the limitations of ground-based monitoring. This study integrates a novel algorithm with satellite imagery to quantify both associated and nonassociated flaring and to calculate gas production during hydrocarbon extraction. The approach enables dynamic gas-oil ratio (GOR) monitoring in the Main Limestone reservoir of northern Iraq, thereby improving dissolved-gas back-allocation and production control. Using daily time-series data from 2018 to 2023, the analysis demonstrates significant trends in flaring reduction from an average of 95 MMscf/d in 2018–2021 to 74 MMscf/d in 2022—largely attributed to changes in production practices. Field-wide GOR and oil production trends reveal strong temporal variability, with GOR values rising from 770 scf/stb in March 2022 to 1040 scf/stb in September, coinciding with declining oil output from 148 to 133 kstb/d. These results highlight the capacity of satellite-derived flaring estimates to uncover operational inefficiencies, inform reservoir management, and guide investment in gas-capture technologies. Model validation against 2023 production data confirms the robustness and reliability of the proposed method, demonstrating its applicability for real-time surveillance, emissions accountability, and optimized gas utilization in petroleum fields.

The power generated by Photovoltaic (PV) systems is influenced by multiple factors, with irradiance and temperature being the most significant. Under Partial Shading Conditions (PSC), uneven irradiance distribution across PV arrays leads to a substantial reduction in output power. Furthermore, the P-V characteristics of PV systems under such conditions exhibit multiple peaks, with the number of peaks increasing proportionally to the number of PV modules. Conventional Maximum Power Point Tracking (MPPT) algorithms, such as Perturb and Observe (P&O), Hill Climbing (HC), and Incremental Conductance (INC), struggle to locate the global maximum power point (GMPP) on the P-V curve in these scenarios. To address the limitations of the Coot Optimization Algorithm (COA)—specifically its slow tracking speed and significant oscillations under PSC, this paper proposes a Levy Flight-enhanced Coot Optimization Algorithm (LF-COA) for global MPPT of PV systems under shading conditions. Static and dynamic irradiance simulation experiments conducted in MATLAB/SIMULINK demonstrate that LF-COA outperforming the Modified Firefly Algorithm (MFA), Improved Particle Swarm Optimization (IPSO) algorithm, and the conventional COA in performance metrics.

Mountain climbing often involves sudden weather changes, group separation, and mobile device battery depletion, which can lead to life-threatening emergencies. Enhancing survival and extending rescue time in such situations are crucial, making power supply and emergency equipment essential considerations. Existing equipment designs have emphasized solar power, lighting, communication, or navigation, but few address an integrated solution that simultaneously addresses survival needs such as warmth, power supply, and location tracking. To overcome these limitations, this study presents the design of an emergency rescue backpack, which serves as a self-rescue and assisted-rescue tool for climbers stranded in mountainous terrain. The backpack is equipped with light emitting diode (LED) light strips, a heating module, a global positioning system (GPS) tracking system, and a flexible solar photovoltaic panel integrated with a portable power bank. A key innovation of this study lies in the integration of the heating module, which utilizes a carbon fiber heating element sewn into the back of the backpack. By hugging the backpack, climbers can generate and retain heat to help maintain body temperature in cold environments, thereby reducing the risk of hypothermia. Additionally, the LED lighting provides illumination for nighttime navigation and deters wildlife. The GPS enables rescuers to track the stranded individual's location via satellite positioning. The flexible solar panel converts sunlight into electrical energy, which is stored in the internal power bank. Moreover, a switch-controlled USB hub with four ports is installed to minimize power consumption when not in use. Therefore, the practical contribution of the overall design is to extend rescue time and enhance the survival chances of lost hikers.

This article provides a methodological guide for applying SWOT analysis to Turkiye's solar photovoltaic (PV) market and shows how local developers can translate sector‑level insights into firm‑level strategies. The study clarifies scope: it does not report an empirical SWOT; instead, it offers an illustrative matrix (Table 3) and a three‑step pathway—mapping, strategic priorities, and actionable recommendations—operationalized in Table 4. Drawing on policy documents, market reports, and academic literature, guidance is outlined on how factors such as regulatory design, financing access, regional solar resource variation, and technology trends (e.g., storage and smart grids) should be incorporated into a structured SWOT. The approach is positioned alongside complementary methods, and the regional solar equity model (RSEM) is briefly introduced as a conceptual tool for region‑sensitive policy design. Limitations are noted: the guide synthesizes secondary sources without primary data collection; empirical validation, prioritization (e.g., via MCDM), and RSEM calibration are proposed for future work. The guide aims to support researchers and practitioners designing market entry and growth strategies consistent with national energy objectives.

This study explores the effects of surface wettability and particle size distribution on the stability of petroleum coke–water slurry (PCWS). Significant differences in stability were observed among slurries prepared from four types of petroleum coke. Notably, reduced surface wettability was found to enhance slurry stability. The average particle size of all petroleum coke powders was consistently maintained at 23 ± 5 μm, with their size distributions well fitted by the Rosin–Rammler equation. The model parameter n, ranging from 0.60 to 0.84, indicates a relatively uniform particle size distribution, suggesting improved packing efficiency within the slurry. As a result, PCWSs with particle size distributions falling within this optimal range exhibited markedly higher stability than those outside it. The novelty of this study lies in the combined quantitative investigation of two fundamental physicochemical factors—surface wettability (via contact angle) and particle size distribution (via Rosin–Rammler model parameters)—and their synergistic influence on the static stability of PCWS.

In the process of fracturing, proppant flowback is unavoidable, and excessive proppant flowback will cause sand plugging in the wellbore, change the morphology of proppant fractures, reduce the effective flow-conducting capacity of fractures, weaken the effect of fracturing to increase production, and affect the extraction of hydrocarbons in the later stage of the fracturing process. At present, the research on proppant flowback during fracturing and re-discharge process mainly focuses on the force of proppant and its critical flowback rate at the time of startup, and there are fewer studies on the factors affecting proppant flowback, and there is not yet a theoretical model to specifically analyze the flowback characteristics of proppant in a rough fracture. Combining the above reasons, this paper constructs a three-dimensional numerical simulation model of proppant flowback in rough fracture by using the coupled computational fluid dynamics-discrete element method to study the factors affecting proppant flowback in rough fracture, and it is found that the rough fracture can reduce the flowback of proppant by comparing the flowback of proppant in the smooth fracture and the rough fracture. Meanwhile, it is clearly understood that the flow rate of return fluid and proppant particle size are the main influencing factors affecting proppant flowback. This study can provide theoretical references for the program design and field construction of the actual fracturing return phase.

To address the problem of the chaos phenomenon caused by the parameter drift of a doubly-fed induction generator (DFIG) due to a changing operating environment, a fractional-order stator voltage/flux-oriented control model is developed, and bifurcation theory and numerical simulations reveal that the chaos mechanism originates from supercritical pitchfork bifurcation. First, the fractional-order DFIG model is constructed by introducing Caputo fractional-order derivatives and combining linear affine transformation and time-scale transformation. Second, we analyze the bifurcation characteristics of the system's equilibrium point under diverse axial rotor voltages. Third, we apply the central manifold theorem to reduce the system dimensions to derive an equivalent downscaling model and describe the bifurcation behavior near the equilibrium point. Finally, the dynamics of the DFIG system at different fractional orders are explored by employing different numerical simulation methods for the changes in the rotor d-axis voltage component and the wind turbine output torque. The analytical results indicate that the DFIG system plunges into chaos via supercritical pitchfork bifurcation. As the fractional order diminishes, the system transitions from chaotic conditions to stable conditions. Transient chaos can occur in the DFIG system under particular combinations of fractional orders and parameters.

The integration of hydrogen into existing natural gas networks represents a transformative approach to enhancing the utilization of renewable energy sources. This study focuses on the reliability of systems designed for hydrogen injection into the natural gas grid. We develop a representative system configuration and compile failure/repair data for all major components, then perform a component-level failure mode and effect analysis (FMEA) with exponential-rate assumptions to quantify subsystem and plant reliability. In the baseline (no redundancy), the overall mean time to failure (MTTF) is 186 h. Selective parallelization of pumps and compressors in Subsystems 2–5 (three units in parallel each) increases the plant-level MTTF to ~226 h (+21%), while additional parallel units show diminishing—and eventually negative—returns due to extra failure paths (valves, piping). A severity-probability (S–P) matrix pinpoints pumps and compressors as the dominant contributors to risk; control valves exhibit high impact but are not good candidates for redundancy, and the fresh water pump shows no benefit from duplication. These results provide practical guidance on where redundancy is worth the complexity and cost, and they outline priorities for future validation with hydrogen-specific field data.