Future Energy

Experimental investigation of MHD mixed convection in an inclined elliptic enclosure saturated with Al2O3-water nanofluid

T. Adekeye — 2026-01-21

This study experimentally investigated the effects of geometric parameters, inclination, magnetohydrodynamic properties, flow-on-flow behaviour, and axial heat transfer in an oriented elliptic enclosure filled with Al₂O₃ nanofluid. An experimental rig was locally fabricated and set up to examine MHD mixed convection in an inclined elliptic enclosure subjected to continuous heat flux at the center of the test-section of 0.4 m with the aid of a surface heater, and the top air was cooled, while the 0.3 m on either side of the geometry were insulated using fiberglass of 1.5 cm thickness. The effects of nanoparticle volume fractions and inclination angles on the thermal field were examined and discussed under laminar flow conditions. The results showed that the magnetic field effect on nanoparticle volume concentrations deteriorated with fluid flow strength (velocity profiles). At 0inclination angle, 28% heat transfer enhancement was achieved, while 30 inclination showed 24 % augmentation, and 60 inclination angle presented approximately 23% enhancement. Additionally, the rate of heat transfer for φ at 4.5% (0.045) nanoparticle volume fraction was found to be almost 10% higher than that of the base fluid (distilled water), φ at 0%. Close observation revealed that, in all cases, T_wall values were slightly higher than T_fluildand both increased with inclination angle and nanoparticle volume fraction. The percentage difference for Re at 400 mm, 600 mm, and 800 mm values along the axial direction with respect to the rate of heat transfer was not significant for angles of inclinations 0, 30 and 60.

Allocating currency risk in renewable power finance: tariff indexation, hedging, and sovereign guarantees

Alma Yerzhanova — 2026-02-08

Emerging nations' renewable energy investments are frequently hampered by currency risk resulting from the mismatch between local-currency revenues and foreign-currency funding. Though financial hedging, tariff indexation, and sovereign guarantees are often employed to reduce this risk, present studies usually treat these tools separately. Under exchange-rate uncertainty, this study creates a single framework combining all three channels into a unified project-finance model of renewable energy investment. Key features of renewable energy finance are captured by the model, including long-term power purchase agreements, limited hedging markets, and government involvement through guarantees. It defines how, in equilibrium, tariff indexation, private hedging, and government guarantees interact to distribute currency risk among investors, consumers, and the public sector. The research reveals three major observations. Private hedging first reacts endogenously to governmental policy decisions; more indexation or guarantees crowd out financial risk management. Second, while financial hedging rules in deep markets prevail, tariff indexation is somewhat more successful in volatile settings. Third, while sovereign guarantees enhance project bankability, they could transfer risk to public balance sheets. The paper proposes a least-cost risk absorption principle and offers advice on creating currency-risk reduction plans that strike a compromise between fiscal sustainability and investment incentives.

Ethiopia's quest for energy security: challenges and policy options

Tesfaye Bezabih Gezihagne — 2026-03-15

Energy security is at the heart of leveraging economic growth and social development, as well as environmental sustainability in third-world countries. An alarming rate of population growth, the society’s energy demand, and the expansion of manufacturing and industrial production have further strained an already structurally vulnerable energy system in Ethiopia. Despite the country having made vital investments in renewable energy, particularly in hydropower, it still faces challenges related to climate variability, unequal access, institutional fragmentation, and regional geopolitics. This study examines Ethiopia as a multidimensional nation in terms of its energy security by assessing the social, environmental, institutional, and geopolitical constraints. The research employs a qualitative case study design, based on semi-structured interviews with key stakeholders and an in-depth review of policy documents, official government reports, and international datasets. Likewise, document review, as a tool, and thematic analysis, as a research method, are used to identify key patterns, risks, and policy gaps in energy system resilience. The results of the study showed that the high dependence on climate-dependent hydropower sources in Ethiopia presents the energy industry to supply volatility and financial difficulties, particularly in dry seasons. Poor rural electrification, reliance on traditional biomass, and inadequate transmission infrastructure are key drivers of end-of-life energy poverty and social imbalance. Institutional coordination issues and insufficient funds to expand these sources are among the barriers to diversifying renewable energy sources. Regularly, exporting electricity to foreign nations entails economic and diplomatic benefits, as well as political tensions and regulatory uncertainties. In the study, the researcher emphasizes the necessity of a comprehensive energy security system comprising climate resilience, social equity, institutional coherence, and proactive regional diplomacy. Policy guidelines focus on diversifying the energy mix, strengthening governance systems, decentralizing energy systems, and improving cross-border collaboration. The overall, inclusive approach can help Ethiopia increase the reliability, affordability, and sustainability of its energy system, as well as support national and regional development in the long term.

Socio-energetic stamina in photovoltaics: material security and distributed manufacturing potential of Kesterite (CZTSSe)

Tayfun Buke — 2026-03-18

Energy transitions face a materials paradox because solar resources are widely distributed, but photovoltaic systems require supply chains that operate from specific geographic locations and rely on certain thin-film technologies that use rare byproduct metals. The study investigates kesterite photovoltaics (Cu2ZnSn(S,Se)4; CZTSSe) as an energy solution for locations facing energy insecurity that require policies that go beyond cost-effective electricity to include supply security, manufacturing access, and dependable service delivery. We develop a multi-criteria assessment combining (i) indicators of mineral scarcity and refining concentration, (ii) benchmarked manufacturing capital intensity with scale adjustment, and (iii) scenario-based techno-economic analysis that incorporates grid unreliability through avoided outage costs (VoLL). Refining concentration for indium and gallium is extreme (HHI > 6,000), whereas key CZTSSe constituents exhibit substantially lower concentration. A 30 TW deployment stress test indicates that large-scale CIGS expansion faces severe indium constraints even under optimistic recycling, while for CZTSSe, the binding concern shifts toward tin reserve definitions, reserve growth, and end-of-life recovery for bulk metals. We introduce socio-energetic stamina as a development-relevant lens for comparing PV options by material security, manufacturability, and operational resilience, clarifying where efficiency-first evaluation can misrank technologies when reliability and import dependence shape real-world energy access outcomes.

A comprehensive review of recent advances in biomass pyrolysis: feedstock characteristics, thermal decomposition mechanism, temperature, heating rate, residence time, and particle size on product distribution

Mohammad Ashraful Islam — 2026-04-04

Biomass pyrolysis is a promising thermochemical conversion pathway for producing renewable fuels, value-added chemicals, and carbon-based materials from sustainable feedstocks. However, the complex and highly sensitive nature of pyrolysis reactions, governed by biomass composition, operating conditions, and reactor design, continues to challenge predictive control and large-scale deployment. This review provides a comprehensive and critical synthesis of recent advances in biomass pyrolysis, with particular emphasis on feedstock characteristics; the thermal decomposition mechanisms of cellulose, hemicellulose, and lignin; and the influence of key operational parameters, such as temperature, heating rate, residence time, and particle size, on product distribution. Special attention is given to reaction intermediates and pathways identified through advanced analytical techniques, including Py-GC/MS, TG-FTIR, two-dimensional photoionization mass spectrometry, and complementary molecular-level simulations such as density functional theory and reactive molecular dynamics. By systematically integrating experimental observations with mechanistic insights, this review highlights current limitations, including the lack of unified kinetic models, weak coupling between experiments and simulations, and insufficient investigation of high-temperature pyrolysis regimes above 800 °C. Emerging opportunities for data-driven and machine-learning-assisted kinetic modeling are also discussed as a pathway to address biomass heterogeneity and complex reaction networks. The findings presented herein aim to support the development of predictive pyrolysis models, optimized reactor design, and the sustainable valorization of biomass within future bioenergy and biorefinery systems.