The influence of Molybdenum diselenide (MoSe2) as an interfacial layer between Cu(In,Ga)Se2 (CIGS) absorber layer and Molybdenum (Mo) back contact in a conventional CIGS thin-film solar cell was investigated numerically using SCAPS-1D (a Solar Cell Capacitance Simulator). Using graded bandgap profile of the absorber layer that consist of both back grading (BG) and front grading (FG), which is defined as double grading (DG), attribution to the variation in Ga content was studied. The key focus of this study is to explore the combinatorial effects of MoSe2 contact layer and Ga grading of the absorber to suppress carrier losses due to back contact recombination and resistance that usually occur in case of standard Mo thin films. Thickness, bandgap energy, electron affinity and carrier concentration of the MoSe2 layer were all varied to determine the best configuration for incorporating into the CIGS solar cell structure. A bandgap grading profile that offers optimum functionality in the proposed configuration with additional MoSe2 layer has also been investigated. From the overall results, CIGS solar cells with thin MoSe2 layer and high acceptor doping concentration have been found to outperform the devices without MoSe2 layer, with an increase in efficiency from 20.19% to 23.30%. The introduction of bandgap grading in the front and back interfaces of the absorber layer further improves both open-circuit voltage (VOC) and short-circuit current density (JSC), most likely due to the additional quasi-electric field beneficial for carrier collection and reduced back surface and bulk recombination. A maximum power conversion efficiency (PCE) of 28.06%, fill factor (FF) of 81.89%, JSC of 39.45 mA/cm2, and VOC of 0.868 V were achieved by optimizing the properties of MoSe2 layer and bandgap grading configuration of the absorber layer. This study provides an insight into the different possibilities for designing higher efficiency CIGS solar cell structure through the manipulation of naturally formed MoSe2 layer and absorber bandgap engineering that can be experimentally replicated.

Nowadays, renewable energy is a reliable solution for addressing global warming and fossil fuel depletion issues. Malaysia has an abundance of biomass resources currently underutilized to generate electricity, such as palm oil waste. Wastes from a palm oil mill plant, such as empty fruit bunch (EFB), palm mesocarp fibre (PMF), and palm kernel shell (PKS), are worth to be investigated as a possible raw material for co-firing with coal. The co-firing technique is the low-cost risk approach for the utilization of biomass in electricity generation. This paper aims to review and perform a comparative study on the existing co-firing biomass processes worldwide in order to explore the potential of using palm oil wastes with coal. To achieve successful co-firing of biomass with coal, the feedstock characteristics need to be understood before undergoing several pre-treatment options. It is recommended to implement co-firing palm oil waste with coal in Malaysia because palm oil wastes can reduce greenhouse gas, NOX, and SOX. Co-firing of palm oil wastes in existing coal-fired power plants is one of the practical ways to be implemented as it helps to reduce the over-consumption of fossil fuels. Based on the findings, Malaysia seems to be on the right track to maximize the use of palm oil wastes either in a standalone biomass power plant or in a co-firing power plant. The improved utilization will further minimize the negative impact of the greenhouse gas emission from the untreated palm oil mill wastes.

<abstract> <p>Energy is seen as one of the most determinant factors for a nation's economic development. The Sun is an incredible source of inexhaustible energy. The efficiency of the conversion and application of Photovoltaic (PV) systems is related to the PV module's electricity generation and the location's solar potentials. Thus, the solar parameters of a region are important for feasibility studies on the application of solar energy. Although solar energy is available everywhere in the world, countries closest to the equator receive the greatest solar radiation and have the highest potential for solar energy production and application. Dhofar in Salalah-Oman is one of the cities in Oman with high temperatures all year round. The city has been reported to exhibit a maximum solar flux of about 1360 w/m² and a maximum accumulative solar flux of about 12,586,630 W/m² in March. These interesting solar potentials motivated the call for investment in solar energy in the region as an alternative to other non-renewable energy sources such as fossil fuel-powered generators. As a consequence, several authors have reported on the application of different solar energy in the different cities in Oman, especially in remote areas and various results reported. Therefore, the present review highlighted the achievements reported on the availability of solar energy sources in different cities in Oman and the potential of solar energy as an alternative energy source in Dhofar. The paper has also reviewed different PV techniques and operating conditions with emphasis on the advanced control strategies used to enhance the efficiency and performance of the PV energy system. Applications of standalone and hybrid energy systems for in-house or remote power generation and consumption in Dhofar were discussed. It also focused on the relevance of global radiation data for the optimal application of PV systems in Dhofar. The future potential for the full application of solar systems in the region was mentioned and future work was recommended.</p> </abstract>

Renewable energy is a reliable solution for addressing global warming and fossil fuel depletion issues. Due to the abundance of biomass resources, such as palm oil wastes, which are currently underutilised, this is an opportunity for Malaysia to seize and implement this renewable energy solution for power generation. Palm oil mill wastes, such as empty fruit bunch (EFB), palm mesocarp fibre (PMF), and palm kernel shell (PKS), are worth to be investigated as a possible feedstock for combustion in thermal power plants. Co-combustion or co-firing of biomass in coal-fired thermal power plants offers a significant potential to reduce harmful emissions and represents a low cost and low-risk method. This paper aims to review and compare existing biomass thermal combustion technologies globally to evaluate the potential of utilising palm oil waste with coal. Before undergoing various pretreatment options, it is necessary to understand the feedstock characteristics for thermal power plant combustion. It is recommended to implement the combustion of palm oil wastes with coal in Malaysia to reduce harmful pollution. Based on the findings, Malaysia appears to be on the right track to optimise the use of palm oil wastes for electricity generation. The enhanced usage will reduce the negative impact of greenhouse gas (GHG) emissions.

<p>Most numerical studies on flow over buildings simplify the geometry of the roof and assume that it is flat. This may lead to misrepresentation of the flow as the roof of actual buildings contains some sort of roughness. In this study, the flow over the administrative building of Universiti Tenaga Nasional is investigated for multidirectional flow conditions. The actual topology of the building is gridded and simulated using the steady-state Reynolds-averaged Navier-Stokes equation. Four points at the top of the building are identified and the wind statistics at these designated locations at three different heights are investigated. The optimal location with the highest average wind speed and consistent wind speeds for all wind angles is identified and is earmarked as a potential location to install the wind turbine.</p><p><em> </em></p>