Advances and challenges in grid tied photovoltaic systems

Photovoltaic (PV) technology is gathering momentum around the word. Global PV energy harvest has been more than doubled since 2010. Grid connected PV (GCPV) systems can be found in different scales classified into three categories of small scale, medium scale and utility scale. Considering size of the system various configurations are suggested for the GCPV systems while each configuration might be assessed by factors such as efficiency, reliability, expandability and cost. Moreover, high integration of GCPV systems into the power system network creates several technical problems mostly coming from the intermittent nature of solar energy. In addition, to achieve a higher degree of power system reliability, GCPV systems are required to support the grid in abnormal condition such a faults and deviation from standard frequency. This paper provides a comprehensive review on GCPV systems. Various configuration proposed by the literature will be discussed. Cost study and impact of technical and environmental factors on the total expense and revenue of GCPV installation will be investigated. Different aspects of PV integration into the power network will be discussed. Problem and solutions will be studied as well. Finally grid requirements and active and reactive power support will be reviewed. (C) 2015 Elsevier Ltd. All rights reserved

Optimization of fuel injection parameters of moringa oleifera biodiesel-diesel blend for engine-out-responses improvements

Biodiesel has gained popularity in diesel engines as a result of the rapid decline of fossil fuels and population growth. The processing of biodiesel from non-edible Moringa Oleifera was investigated using a single-step transesterification technique. Both fuels had their key physicochemical properties measured and investigated. In a common-rail diesel engine, the effects of MB50 fuel blend on the symmetric characteristics of engine-out responses were evaluated under five load settings and at 1000 rpm. As compared to standard diesel, MB50 increased brake thermal efficiency (BTE), and nitrogen oxides (NOx) emissions while lowering brake specific fuel consumption (BSFC), and smoke emissions for all engine loads. A further study of injection pressure and start of injection (SOI) timing for MB50 fuel was optimized using response surface methodology (RSM). The RSM optimization resulted in improved combustion dynamics due to symmetry operating parameters, resulting in a simultaneous decrease in NOx and smoke emissions without sacrificing BTE. RSM is an efficient optimization method for achieving optimal fuel injection parameter settings, as can be deduced. As a result, a clearer understanding of the use of MB50 fuel in diesel engines can be given, allowing for the best possible engine efficiency

Physicochemical and tribological properties of microalgae oil as biolubricant for hydrogen-powered engine

Hydrogen fuel offers a cleaner fuel alternative to fossil fuel due to more efficient burning as well as reduces the environmental and health issues brought by fossil fuel usage. In engine application, regardless of either pure hydrogen or in combination with air or/and other biofuel, all the moving parts are exposed to friction and wear, and lubricant is used to minimize friction and wear for optimum operation. Thus, in this study, the use of microalgae oil as an alternative biolubricant is evaluated from the physicochemical and tribological aspects. It is found that modified microalgae oil (MMO) has demonstrated great anti-friction and anti-wear potential, particularly the 10% modified microalgae oil blend (MMO-10). The coefficient of friction is reduced (up to 10.1%) and significant reductions of wear loss and surface roughness are obtained in comparison to pure poly-alpha-olefin. Lubricant's heat dissipation is also enhanced with MMO addition, demonstrating great prospect for MMO for hydrogen-powered engine utilization

Promoting deoxygenation of triglycerides via Co-Ca loaded SiO2-Al2O3 catalyst

Triglycerides and fatty acid derivatives can be converted to hydrocarbon-grade green diesel that are entirely fungible to the fossil fuels. In the present study, deoxygenation (DO) process of triolein was studied by using mesoporous SiO2-Al2O3 supported Co-Ca catalyst. The presence of active metals (Co-Ca) showed high DO activity exclusively via decarboxylation/decarbonylation (deCOx) pathways with maximum hydrocarbon n-(C8-C20) yield of 73%, and high selectivity of n-C15 and n-C17 fractions. This results suggested the acid-base active sites of catalyst provide selective deCOx pathway of triglycerides structure. In additional, the presence of high surface area of Co-Ca/ SiO2-Al2O3 enhance the metal dispersion for better accessment of large molecular reactant with catalyst during DO process. An optimum Co metal content (10 wt.%) for deCOx reaction was observed, while an excess Co content is not preferable due to tendency of cracking effect. The efficiency of Co-Ca/SiO2-Al2O3 was investigated by using non-edible feedstock (e.g. Ceiba oil and Sterculia oil) along with catalyst stability study were carried out. Resulst also indicated that degradation of DO activity was due to the formation of coke

Comparative study of nanoparticles and alcoholic fuel additives-biodiesel-diesel blend for performance and emission improvements

This study aims to investigate a CI diesel engine characteristic of diesel-biodiesel blend with oxygenated alcohols and nanoparticle fuel additives. Biodiesel was synthesized from a complementary palm-sesame oil blend using an ultrasound-assisted transesterification process. B30 was mixed with fuel additives as the base fuel to form ternary blends in different proportions before engine testing. The oxygenated alcohols (DMC and DEE) and nanoparticles (CNT and TiO2) were used to improve both the fuel characteristics and engine emission and performance parameters. B30 fuel was mixed with 5% (DEE) and 10% (DMC) by volume and 100 ppm concentration of CNT and TiO2 nanoparticles, respectively, which are kept constant during this study. Engine performance and emissions characteristics were studied using a CI diesel engine with variable engine rpm at full load condition. The results were compared with B30 fuel and B10 (commercial diesel). The main findings indicated that the B30 + TiO2 ternary blend shows an overall decrease in brake specific fuel consumption up to 4.1% among all tested fuels. B30 + DMC produced a higher 9.88% brake thermal efficiency, among other fuels. B30 + DMC ternary blend showed a maximum decrease in CO and HC emissions by 29.9% and 21.4%, respectively, collated to B30. B30 + CNT ternary blend showed a maximum reduction of 3.92% in NOx emissions compared to B30

Effect of additivized biodiesel blends on diesel engine performance, emission, tribological characteristics, and lubricant tribology

Abstract: This research work focuses on investigating the lubricity and analyzing the engine characteristics of diesel–biodiesel blends with fuel additives (titanium dioxide (TiO2) and dimethyl carbonate (DMC)) and their effect on the tribological properties of a mineral lubricant. A blend of palm–sesame oil was used to produce biodiesel using ultrasound-assisted transesterification. B30 (30% biodiesel + 70% diesel) fuel was selected as the base fuel. The additives used in the current study to prepare ternary fuel blends were TiO2 and DMC. B30 + TiO2 showed a significant reduction of 6.72% in the coefficient of friction (COF) compared to B30. B10 (Malaysian commercial diesel) exhibited very poor lubricity and COF among all tested fuels. Both ternary fuel blends showed a promising reduction in wear rate. All contaminated lubricant samples showed an increment in COF due to the dilution of combustible fuels. Lub + B10 (lubricant + B10) showed the highest increment of 42.29% in COF among all contaminated lubricant samples. B30 + TiO2 showed the maximum reduction (6.76%) in brake-specific fuel consumption (BSFC). B30 + DMC showed the maximum increment (8.01%) in brake thermal efficiency (BTE). B30 + DMC exhibited a considerable decline of 32.09% and 25.4% in CO and HC emissions, respectively. The B30 + TiO2 fuel blend showed better lubricity and a significant improvement in engine characteristics

Sustainability of palm biodiesel in transportation: a review on biofuel standard, policy and international collaboration between Malaysia and Colombia

Biodiesel is gaining prominence as a superior alternative source of energy to replace petroleum-based fuel in transportation. As of today, the biodiesel market continuous to rise up as the biofuel has been introduced to more than 60 countries worldwide. The aim of the present review is to highlight on the scenario of the biofuel implementation in transportation sector towards sustainable development in Colombia and Malaysia. Colombia serves as an ideal comparative case for Malaysia in terms of biodiesel development since the country is the main palm oil producer in Latin America region and the pioneer in bioethanol industry. The first section shows an overview on the biodiesel as an alternative fuel in transportation. The next section will focus on a comparative study between Malaysia and Colombia biodiesel sector in terms of energy supply, resource, production and consumption, standards, techno-economic cost and their biodiesel policies. A comprehensive review was studied to discuss on the sustainability of palm cultivation and biodiesel, impact of palm industry and biodiesel policy in transportation sector and potential international collaboration between Malaysia and Colombia to improve their existing policies, strategies and blueprints related to the palm biodiesel industry, thus overcoming the challenges when dealing with global energy issue

Techno-economic analysis of biodiesel production from palm, Jatropha curcas and Calophyllum inophyllum for road transport in Malaysia / Ong Hwai Chyuan

Transportation sector has a dominant role in global fuel consumption and greenhouse gas emissions. Due to the dramatic increase in greenhouse gas emission, sustainable development of this sector has raised the concern in many countries including Malaysia. Biodiesel is a renewable energy that has great potential to serve as an alternative fuel to fossil diesel in the compression ignition (CI) engine. Although Malaysia is one of the biggest biodiesel fuel producers, the commercialization of biodiesel has not been fully undertaken in a large scale. Besides the technical barriers, there are several nontechnical limiting factors, which impede the development of biodiesel. A wide variety of biodiesel research on transesterification, performance and emission analysis is currently available worldwide. However, the study on techno-economic and feasibility of biodiesel fuel for Malaysian condition is limited. Therefore, this study is focused on biodiesel production and techno-economic comparison among palm, jatropha curcas and calophyllum inophyllum biodiesel as transportation fuel in Malaysia. Moreover, the present study attempts to find out the impact of biodiesel implementation towards the energy scenario, environmental and economy. The total CO2 equivalent emissions for road transport are 59,383 million kg. Therefore, alkaline catalyst transesterification process is used to produce palm, jatropha curcas and calophyllum inophyllum biodiesel as biofuel for road transport vehicles. It was found that the life cycle cost for 50 ktoe palm, jatropha curcas and calophyllum inophyllum biodiesel production plant with an operating period of 20 years is $764,$583 and $604 million respectively. The largest economic factor for biodiesel production is feedstock cost. Furthermore, replacing 5% of diesel with biodiesel in road transport vehicles can reduce the CO2 emission up to 1200 million kg in year 2031. In order to repay the carbon debt from land converting to feedstock cropland, calophyllum inophyllum biodiesel requires the lowest cropland and ecosystem carbon payback period compared to palm and jatropha curcas biodiesel due to the high oil yield which is 4680 kg/ha. When the subsidy policy and tax exemption are implemented, biodiesel fuel is more competitive than fossil diesel at the current production costs. Apart from that, the key factor for biodiesel fuel to be able to compete with diesel fuel is due to the high crude petroleum price coupled with low feedstock oil price. Therefore, this study serves as a guideline for further investigation and research on biodiesel production, subsidy cost and other limiting factors before the wider utilization of biodiesel in Malaysia

Iron oxide reduction by torrefied microalgae for CO2 capture and abatement in chemical-looping combustion

Biomass provides a sustainable source for iron oxide reduction and can replace coal for mitigating CO2 emissions. Torrefied biomass can act as a reducing agent in the iron oxide reduction to metallic iron which is important in chemical-looping combustion for lessening CO2 emissions. This study performs iron oxide reduction by graphite and torrefied biomass via thermogravimetric analysis (TGA), while the evolved gases from the reduction processes are analyzed using a Fourier transform infrared (FTIR) spectrometer. Iron ore reduction by graphite occurs at higher temperatures (\u3e950 °C), whereas iron oxide reduction using the torrefied biomass is more significant for low-to medium-range temperatures with an onset temperature of 300 °C. The reduction extent is recognized from the comparison between theoretical and experimental TGA curves, and validated by the evolved gases. The reduction extent of the 2:1 ratio of hematite-to-torrefied biomass shows a lower onset reduction temperature compared to the 1:1 ratio. The TG-FTIR results confirm the direct reduction of iron oxides by carbon in graphite and torrefied biomass and the release of evolved CO2 instead of CO. A step-wise reduction procedure is observed which is triggered by the evolved gases released from torrefied biomass devolatilization at 370 °C. © 2019 Elsevier Lt

Microalgae Biomass as Biofuel and the Green Applications

With the increasing concern on the global energy security and environmental sustainability [...