Modeling and Design Optimization of Looped Water Distribution Networks using MS Excel: Developing the Open-Source X-WHAT Model

A systematic review of pico-scale Turgo turbine optimization for rural electrification: velocity triangle analysis, CFD, and additive manufacturing approaches

A Cost Calculation Framework for Fuel Transport Tariffs Using Multi-Vessel Waterway Operations in Remote and Underdeveloped Areas of Indonesia

Fuel distribution in remote and underdeveloped regions of Indonesia faces significant challenges due to complex geographical conditions, diverse transportation modes, and inconsistent tariff calculation mechanisms. These challenges may affect the efficiency, transparency, and sustainability of the national fuel supply system, particularly within the BBM Satu Harga program. This study aimed to develop a standardized cost calculation framework for fuel transportation tariffs using multi-vessel waterway operations to support more accurate, equitable, and risk-based tariff determination. The research employed a mixed-method approach combining qualitative and quantitative methods through regulatory analysis, field data collection, route identification, cost component assessment, and simulation modeling. Data were obtained from service providers, operational regions, and relevant institutional sources, followed by the development of a Microsoft Excel-based tariff calculation framework. The results showed that the proposed framework successfully integrated six major cost components, including vessel costs, own-use fuel consumption, packaging, human resources, administrative and certification costs, and overhead expenses. The framework also incorporated load factor mechanisms, route-based adjustment factors, and safety incentives to accommodate operational risks and geographical variations. Simulation results across several regions demonstrated that the proposed tariffs were generally consistent with existing contract tariffs, while differences were primarily attributed to incomplete cost structures, negotiation-based pricing, and variations in vessel specifications. This study concluded that the developed framework provided a comprehensive and transparent approach for standardizing fuel transport tariffs and improving distribution efficiency in remote areas of Indonesia.

Operations-Research Decision Support for Industrial Resource Clusters: A Multi-Objective Linear-Programming Framework for Multi-Origin Water Allocation in a Mediterranean Brewery

Water-intensive industries in the Mediterranean face supply stress and decarbonisation pressure simultaneously. We develop an operations-research decision-support framework that treats the firm as one node of a small industrial resource cluster and prices the cost and carbon-equivalent emissions of five alternative supply trains—municipal water, river water, groundwater, rainwater harvesting and brewery wastewater reuse—within a multi-objective Linear Program. Each train carries engineering-grounded expenditures, energy intensities and grid emissions, and a weighted-sum scalarisation is solved daily for 365 days under three managerial scenarios. On a Cretan microbrewery whose 2022 demand of 5250 m3 is met from the municipal network, the balanced and cost-focused scenarios coincide on a single optimum that cuts the Levelised Cost of Water by 25.3% and emissions by 40.7%, while the eco-friendly scenario yields a 19.3% cost and 51.7% emissions reduction. LP duality, shadow prices and an extended sensitivity programme (diversification, capacity, grid factor, discount rate, RO recovery and demand profile) turn the optimisation into a decision-support package: optimal daily allocations, shadow-price signals on capacity and demand, and robustness diagnostics for capital planning, dispatch and risk management. Results are site-specific, but the framework and its diagnostics transfer in structure to clusters sharing the same convex-polytope source geometry; transposition to energy cooperatives is future work.

Life-Cycle Planning of Collector System for Deep-Sea Multi-Spatial Wind-PV-Tidal Farm

This paper develops a life-cycle optimization model for the collector system (CS) of deep-sea co-located energy farms (CEFs), where co-located energy turbines (CETs) integrate wind, photovoltaic (PV), and tidal current resources across sea-area layers. The model captures multi-layer marine-space complementarity, wake effects, and output variability, while accommodating diverse dynamic submarine cable configurations. To improve computational efficiency, the adaptive piecewise linearization (A-PWL) method based on the outputs of CETs is proposed to transform the original mixed-integer quadratic programming (MIQP) problem into a mixed-integer linear programming (MILP) form to approximate quadratic operation costs and simplify absolute power flow modeling. Case studies demonstrate that incorporating multi-energy complementarity significantly enhances the economic performance of deep-sea CEFs. When external physical risks are negligible, the fully-suspended cable configuration proves more cost-effective than the lazy-wave design. The proposed linearization method achieves high accuracy while significantly reducing solution time. Overall, this work provides a practical and scalable framework for efficient CS planning in offshore renewable energy systems.

A CFD-based methodology for improved representation of complex hydraulic components in network-scale models: application to irrigation hydrants

Graphical abstract illustrating a multi-scale modelling framework for representing complex hydraulic components in network-scale simulations. The workflow starts with CFD simulation of an irrigation hydrant to quantify component-specific resistance coefficients (Ks) under different operating conditions. These coefficients are then incorporated into an EPANET hydraulic model to improve the representation of head losses and hydraulic behaviour, resulting in more accurate and reliable network-scale hydraulic simulations. Hydraulic network models commonly rely on simplified representations of local energy losses, which can introduce inaccuracies when simulating complex hydraulic components. Multi-outlet hydrants are key control and distribution elements in pressurized irrigation systems, where localized hydraulic behaviour strongly influences pressure distribution and system performance. However, their complex internal configurations are rarely represented in detail within conventional network-scale modelling approaches. This study proposes and validates a computational methodology to improve the representation of complex hydraulic components by transferring CFD-derived hydraulic information to network-scale models developed in EPANET 2.0. The proposed methodology was applied to 12 representative multi-outlet hydrant configurations, with one representative manifold presented in detail as a case study. CFD simulations were used to derive configuration-specific resistance coefficients associated with the singular elements of the hydrant manifold, enabling the characterization of flow behaviour and head losses. The methodology was validated against laboratory measurements, showing high agreement, with root mean square errors below 0.12 m and relative errors generally below 1%. Compared to conventional approaches based on standard coefficients, the method reduces modelling uncertainty and improves head loss estimation. The proposed framework is transferable to other complex hydraulic components, enhancing the reliability of network-scale simulations for water distribution systems.

Developing Annual Delivery Plans in the LNG Industry Under Uncertainty: A Systematic Review and a Conceptual Simulation-Based Optimization Framework

Background: The demand for natural gas and advancements in LNG technologies have made it easier and more cost-effective to transport large quantities of natural gas over long distances by cooling it and then delivering it to customers according to an annual delivery plan (ADP). This plan is crucial for the LNG supply chain to minimize operational costs and meet contractual obligations; however, there are random factors that deviate from the ADP’s initial plan, such as production rate interruptions, weather conditions, and a reduction in the number of berths. Methods: Available optimization methods for ADPs in the literature were reviewed using a systematic literature review (SLR) and validated with the PRISMA 2020 Statement checklist and flow diagram, which showed that many existing studies use simplified deterministic models to optimize ADPs within reasonable time and effort. This research suggests establishing a simulation-based optimization (sim-heuristics) framework to develop ADPs with an objective function that minimizes expected total costs while capturing real-life uncertainties. This approach will provide tactical insights to decision-makers and is adaptable for various operational policy evaluations. Conclusions: This simulation-based optimization approach could offer the LNG industry a powerful analytical engine for robust, real-world decision-making, bridging the gap between theoretical planning and operational complexity.