One of the major challenges facing the energy sectors in practically all developing countries worldwide is clean cooking. In Sierra Leone, only 1% of the population has access to clean cooking, making it one of the worst among the developing countries with clean cooking problems. Many people are switching to improved biomass cookstoves (IBCs), but the unprecedented production of charcoal‑based IBCs and varied designs, particularly ceramic linings, make it difficult for users to choose the right size. The study surveyed major IBC production and sales centres in Sierra Leone’s western regions between 2021 and 2023, examining temperature profiles of the metal stove (MS) and wonder stove (WS). The data showed that an average of 3352 MS and 1833 WS were produced and sold between 2021 to 2023. A water boiling test was adopted for IBCs testing and Testo 310 flue gas analyzer was used to track the temperature profiles of the chosen IBCs. The findings suggest that WS could be able to generate and retain heat more quickly and sustainably than MS. Additionally, the recorded temperatures and timings of all IBCs were also subjected to a systematic correlational analysis. A simulation of the various temperatures and times was also plotted to ascertain the temperature‑time graph differences. These results are relevant and could aid in the analysis of IBC emissions and thermal efficiency. Thus, the results of the study could be utilized to offer policy recommendations for IBC production and sales centres in Sierra Leone and other developing countries.

Among all climatic parameters, solar radiation is one, if not the most, involved in different applications (meteorology, agriculture, environment, etc.). However, due to economic constraints (especially in low‑income countries like ours), it is not always measured. Over the years, several empirical correlations estimating global solar radiation (GSR) have been developed around the world by different authors. The objective of this study is to evaluate the performance and accuracy of a temperature‑based model and to estimate the GSR received at four localities (Nanga Eboko, Ngaoundere, Tchollire and Maroua) in Cameroon. The studied model is that proposed by Hargreaves‑Samani in 1982. It takes into account the latitude of the site and the daily minimum and maximum air temperatures. With commonly used statistical indicators (whose values are all within the acceptable range), the measured and estimated GSR values were compared and analyzed. According to the results, this model gives for the study area, a reasonable degree of good fitting and correlation between measurements and estimations. We also found that the further we move towards the north, the higher solar radiation is received and the performance of the model improves. Thus, from south to north, the country receives in average values, 4.6437 kWh m⁻² d⁻¹ at Nanga Eboko, 5.5667 kWh m⁻² d⁻¹ at Ngaoundere, 5.6968 kWh m⁻² d⁻¹ at Tchollire and 5.7936 kWh m⁻² d⁻¹ at Maroua. In case of missing data and taking into account the foregoing, we can consider the studied model as an accurate and useful tool in predicting GSR in the study area and similar geographical locations around the world.

Harnessing solar energy represents a fundamental pillar of the global transition toward sustainable energy systems due to its abundance, renewability, and broad accessibility. Photovoltaic (PV) technology, in particular, has emerged as the most extensively deployed solution across residential, commercial, and utility‑scale applications. However, the relatively low energy conversion efficiency of PV modules remains a critical challenge, with elevated operating temperatures being one of the primary factors contributing to performance degradation. Excessive heat not only reduces instantaneous electrical output but also accelerates material aging, thereby shortening the service life of PV systems. Consequently, the development of efficient cooling strategies has attracted considerable research attention. In this study, an advanced passive thermal regulation approach based on three‑dimensional pulsating heat pipes (PHPs) was experimentally investigated. Two different inner diameters (2 mm and 3 mm) were designed, and their performance was evaluated using deionized water and graphene oxide (GO) nanofluid as working fluids. The results demonstrate that PHP integration can effectively reduce PV module surface temperatures, leading to notable improvements in electrical efficiency. The most significant enhancement was observed with GO nanofluid at a concentration of 0.8 g/L in 2 mm inner diameter PHPs, achieving up to a 3.2% increase in daily power generation compared with the baseline. Conversely, increasing the pipe diameter reduced the cooling effectiveness, underscoring the importance of geometric optimization and working‑fluid selection in the design of PHP‑assisted PV cooling systems.

Switching to renewable energy is key to environmental resilience, especially with the growing problems of fossil fuel dependence and increasing natural disasters. This study looks into how fossil fuel consumption, natural disasters, and adoption of renewable energy technologies affect carbon dioxide (CO₂) emissions in Turkey and Indonesia. The analysis is based on the Method of Moments Quantile Regression (MMQR) approach, which captures the heterogeneous effects of these variables across different emission levels. Additionally, Feasible Generalized Least Squares (FGLS) is employed as a robustness check to validate the consistency of the results. The findings show that fossil fuel use contributes to higher CO₂ emissions, especially at the lower and middle quantiles. Natural disasters further increase emissions due to the increased energy demand for emergency response and recovery. On the other hand, the expansion of renewable energy leads to consistent and significant reductions of emissions across all levels. These results highlight the need for Turkey and Indonesia to invest in renewable energy infrastructure, implement carbon mitigation policies, integrate disaster risk management in energy planning, and promote innovation in green technologies to achieve long‑term sustainability and environmental protection.

Supply flexibility is an essential attribute for the development of natural gas markets. In countries that have a mature market, gas storage capacity is used to deal with variations in demand. In Brazil, the natural gas market is still developing, and flexibility is an important challenge. In most of the more mature natural gas markets, the seasonality of demand is closely linked to temperature (harsh winter), and flexibility mechanisms were developed for this purpose. In Brazil, demand volatility is determined by the thermoelectric segment, as gas thermal plants have a complementary role to the hydroelectric park. This situation has brought challenges to the development of the gas market in Brazil. Thus, flexibility mechanisms can generate significant efficiency gains by avoiding underutilization of infrastructure. The article analyzes the Underground Storage of Natural Gas (UGS) as a “flexibility” tool, suitable for the Brazilian market to guarantee a balance of supply versus demand without deficits and in an optimized way, considering the randomness of gas demand. The economic value added by UGS to the electricity sector is illustrated through a case study of a natural gas thermoelectric plant that uses pre‑salt associated gas. Thus, using the Monte Carlo simulation method, this study demonstrated the economic value for the Brazilian electricity sector of contracting underground natural gas storage capacity to be used in the dispatch of natural gas‑fired thermal power plants as part of a trade‑off with liquefied natural gas (LNG).