by Wilson C. Chin

Received: 20 June 2026;  Published: 11 September 2026;  doi: 10.21926/jept.2603017

Knowledge of permeability, which measures a rock formation’s resistance to fluid flow, is essential to energy exploration, oilfield development and economic viability, since its value directly relates to cash flow and outlay: the greater permeability is, the faster monetary gains are realized, the lower the initial investment required. Formation testing is crucial to this understanding. It assists with reservoir characterization as it enables direct fluid sampling, reducing the need for resistivity, acoustic and nu [...]

by Wilson C. Chin

Received: 25 May 2026;  Published: 09 September 2026;  doi: 10.21926/jept.2603016

Understanding anisotropy in reservoir dynamics is essential to energy exploration, oilfield development and economic viability since this indicator describes the natural flow directions preferred by the underground fluid. Quantifying its effects allows oil companies to design drilling programs and production facilities that extract the greatest benefit from newly discovered resources. Formation testers are important because they provide direct clues on hydrocarbon properties and resistance to flow through fluid sam [...]

by Ovis D. Irefu  , Godslove I. Ebiega  , Terdoo M. Dugeri  and Seyi J. Fanifosi

Received: 29 April 2026;  Published: 26 August 2026;  doi: 10.21926/jept.2603015

Renewable energy systems play a critical role in reducing carbon emissions and promoting energy sustainability. Conventional battery storage remains the dominant but problematic solution for intermittency management in off-grid renewable energy systems (RES), imposing high capital costs ($150-400/kWh for lithium-ion), short replacement cycles of 3-15 years, and significant environmental burdens from toxic material disposal barriers that are particularly acute in the remote and resource-limited communities that most [...]

by Nathália Dias Araújo  , Patrísia de Oliveira Rodrigues  , Mariana Fornazier Borges  , Anderson Gabriel Corrêa  , Gabriela Ciribelli Santos Pompêu  , Milla Alves Baffi  and Daniel Pasquini

Received: 19 May 2026;  Published: 24 August 2026;  doi: 10.21926/jept.2603014

Organosolv pretreatment is an attractive approach to disrupt the recalcitrant structure of lignocellulosic biomass from agroindustrial wastes, aiming to facilitate its bioconversion into valuable bioproducts. This study investigated the ability of an ethanol/water (1:1 v/v) organosolv pretreatment to improve the enzymatic digestibility of sugarcane bagasse (SB), sugarcane straw (SS), corn straw (CS), and corn cob (CC) for the production of reducing sugars and monosaccharides, aiming at future applications in bioeth [...]

by Daming Zhang

Received: 11 August 2026;  Published: 23 August 2026;  doi: 10.21926/jept.2603013

In this paper, a method for operating AC microgrids in both off-grid or standalone and grid-connected modes is proposed to minimize the use of energy storage by increasing the number of PV panels and curtailing their output power. When the intensity of daylight decreases, power is imported from the main grid through an AC/DC/AC converter or solid-state transformers in parallel to compensate for the shortage. By using a three-phase transformer in Δ-Y connection with Y’s neutral connected to its local grounding syste [...]

by Francis Mafuratidze  , Hagreaves Kumba  , David Ndiyamba  and Ackson Gondo

Received: 27 January 2026;  Published: 08 July 2026;  doi: 10.21926/jept.2603012

Unreliable electricity supply remains a significant barrier to economic development in sub-Saharan Africa, with Zimbabwe experiencing acute load-shedding that disrupts residential, commercial, and industrial activity. This paper presents a techno-economic feasibility assessment of a mini wind turbine for distributed urban energy generation in Zvishavane, Zimbabwe. Wind resource data were sourced from two independent platforms Weather Spark (30-year climatological record) and Meteoblue (high-resolution reanalysis) a [...]

by Kuok Ho Daniel Tang

Received: 04 February 2026;  Published: 22 June 2026;  doi: 10.21926/jept.2602011

Bioenergy plays a differentiated yet increasingly strategic role in national energy transitions, shaped by distinct policy architectures, market structures, and developmental priorities. This review compares the bioenergy policies and markets of China, the United States (US), and India, three of the world’s largest energy consumers, to assess their implications for global bioenergy transitions. China’s bioenergy sector is embedded within a centralized, planning-based governance framework, emphasizing waste-to-energ [...]

by Dudu Mertgenç Yoldaş  , Senai Yalçinkaya  and Mehmet Fatih Yoldaş

Received: 13 January 2026;  Published: 03 June 2026;  doi: 10.21926/jept.2602010

The increasing demand for sustainable energy has accelerated the development of high-performance wind turbine systems. In this context, material selection for turbine blades plays a critical role in ensuring structural efficiency, fatigue resistance, and long-term reliability. This study evaluates the mechanical and structural advantages of carbon fiber-reinforced polymer (CFRP) composites over glass fiber-reinforced polymer (GFRP) materials in wind turbine blade applications. Results from the literature indicate t [...]

by Peter Ebhodaghe Akhator  and Ufuoma Georgina Unueroh

Received: 16 February 2026;  Published: 15 May 2026;  doi: 10.21926/jept.2602009

Waste-derived briquettes offer a promising alternative to fossil fuels and are characterised by low production costs, high volumetric calorific value, robust mechanical strength, and excellent durability. To optimize their adoption, four variants of waste-derived briquettes were produced with different mass ratios of sawdust to polyethylene terephthalate (PET) plastic (100:0, 90:10, 80:20, and 70:30) using high-pressure compaction without binders. Thermogravimetric analysis (TGA) and the Coats-Redfern method were e [...]

by G.-Fivos Sargentis  , Nikolaos Papadodimas  , Ioannis Benekos  , Nikolaos M. Katsoulakos  , Panayiotis Dimitriadis  , Nikos Tepetidis  , Romanos Ioannidis  , Ilias Arvanitidis  , Marios Athanasios Angelidis  , Danai Saperopoulou  , Georgios David Laoutaris  , Matthaios Maravelakis  , Orestis I. Amiralis  , David Markantonis  , Athanasia Alexandridou  , Nikos Mamassis  and Demetris Koutsoyiannis

Received: 20 December 2025;  Published: 20 April 2026;  doi: 10.21926/jept.2602008

The increasing penetration of renewable energy sources (RES) in the energy mix, particularly solar photovoltaic and wind power, poses significant challenges to electricity grid reliability due to their inherent stochastic variability. This study develops a stochastic framework to assess the ability of RES to balance electricity demand, with a focus on storage requirements and reliability implications. Using North Euboea, Greece, as a representative case study, normalized hourly time series of electricity demand, so [...]