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The aim of this research is to examine the techno-economic viability of both off-grid and on-grid hybrid renewable energy systems for Jordan's Al-Karak governorate. Hybrid Optimization of Multiple Energy Resources (HOMER) Pro software was used in this article to evaluate the carry feasibility to maximize the renewable energy (RE) integration in hybrid energy systems based on different configurations, grid-connected and stand-alone systems of the wind turbine, biogas plant, photovoltaic (PV) panels, flywheel, and batteries while minimizing the net present cost, the Levelized cost of energy and CO2 emissions mitigation. The results showed that the PV/Wind system, connected to the grid with batteries for storage is the optimal configuration for sustainable Al-Karak governorate electrification whilst achieving environmental benefits and guaranteeing reliable and continuous energy access with the lowest net present cost and the Levelized cost, 298,359 USD$ and 0.024 USD$/kWh respectively, and high RE share, 71.8% of electricity is generated from wind and 28.2% is purchased from the grid and emits 220 tons of CO2 per year, 53% less than a grid alone system. Such a system would provide advantages in terms of energy independence and improved environmental quality. • A hybrid renewable energy system for Jordan's Al Karak governorate was optimized. • Six different scenarios of renewable energy systems were examined. • The impact of the optimal configuration on GHG emission was analyzed. • PV/Wind/batteries system, connected to grid was the optimal configuration. [ABSTRACT FROM AUTHOR]

The thermal cracking of cotton stalks (CS) through pyrolysis was undertaken using a laboratory scale batch pyrolysis reactor. The distribution of pyrolysis products were studied dependent on the final pyrolysis temperature which ranged from 300 to 800 °C by 100K intervals. The maximum biochar yield of 46.5% was obtained at 400 °C. As the pyrolysis process temperature increased, the solid char product yield decreased. The largest higher heating value (25.845 MJ kg−1) was obtained at 600 °C. All biochar samples produced between 500 and 700 °C had an energy densification ratio of 1.41, indicating a higher mass-energy density than the initial feedstock. A larger share of syngas and bio-oil were produced at higher temperatures, as estimated. Preferential selection of a char based on the energy yield would lead to a selection of the 400 °C product, while selection based on the energy densification ratio would be for a product obtained between 500 and 700 °C. An energy simulation was conducted which determined that the process is self-sustaining at and above 400 °C. Furthermore, the global energy potential was determined from CS pyrolysis, which was estimated at 380 PJ yr−1 could contribute to roughly 0.1% of the actual global total primary energy supply of 576 EJ yr−1. • Biochar yields decrease and syngas yields increase with temperature increase from 300 to 800 °C. • The largest higher heating value (25.8 MJ kg−1) of biochar was obtained at 600 °C. • Process simulation showed that the pyrolysis process is energetically self-sustaining at 400 °C and above. • A temperature of 400 °C is optimal for deriving energy from the biochar. • Global energy potential from pyrolysis CS could contribute to 0.1% of the actual global total energy supply. [ABSTRACT FROM AUTHOR]

Three different waste streams from olive oil production from Montenegro are utilized energetically by hydrothermal carbonization (HTC – hydrochar) and pyrolysis (biochar). Pyrolysis experiments of three-phase olive mill solid waste (3POMSW) were conducted for different pyrolysis temperatures of 450, 550, and 700 °C and a residence of 60 min for each experiment. HTC experiments for two-phase olive mill waste (2POMW) and a mixture of olive mill wastewater (3POMWW) and 3POMSW were carried out at 180, 200, and 220 °C, autogenous pressure of (1, 1.6, and 2.3 MPa) for 60 min. Increasing reaction temperature led throughout all experiments to a lower carbon recovery. Furthermore, all hydrochar and biochar samples had energy densification of more than one, indicating a higher mass-energy density than the initial feedstock. The highest energy yields were achieved for the 3POMW, with 46.48 % in hydrochar treated at 180 °C and 44.09 % in biochar treated at 450 °C. Concerning the hydrochar from 2POMW, the highest energy and mass yields of 62.53 % and 49.65 %, respectively obtained at 180 °C. Summarizing, the energy potential of Montenegro's olive mill waste (OMW) was estimated at 43.69 PJ, which roughly could cover the whole energy demand of the olive oil industry in Montenegro. • Biochar and hydrocar energy potential derived from olive mills waste was evaluated. • Hydrocar derived at 200 °C for 60 min are suitable for substituting peat. • Biochar derived at 450 °C and above are suitable for substituting coal. • Pyrolysis and HTC are feasible methods to provide bioenergy olive mill waste. [ABSTRACT FROM AUTHOR]

Abstract Biogas production of three-phase olive mill solid waste (3POMSW) was studied in lab-scale continuously stirred tank reactors (CSTR) at organic loading rates of 1.5–2.0 g VS L−1 d−1 and temperatures of 35 and 55 °C. To acclimate microorganisms to 3POMSW the start-up phase was performed under thermophilic and mesophilic conditions for 40 days. In order to improve the biogas yield, the enzyme MethaPlus® was added and its effect was investigated. Results indicate that thermophilic processing has a higher biogas yield by 8% compared to mesophilic conditions, but there was no significant difference in methane yield. Under thermophilic conditions, addition of the enzyme to 3POMSW resulted in a significant increase in methane yield by 10%. Under mesophilic conditions, the enzyme did not have a significant effect on biogas yield or reactor performance. The quality of biogas for all experiments was sufficient. Long-term experimentation indicated the beginning of reactor failure. [ABSTRACT FROM AUTHOR]

Cotton stalks (CS) are low-value agricultural residues which are usually burned in the fields, causing a major environmental problem. Bioenergy from agricultural residues has a two-fold advantage over other renewable energy sources: it allows for energy production as well as waste material recovery. In this work, the application of hydrothermal carbonization (HTC) to produce hydrochar from CS was investigated. The HTC experiments were carried out in a laboratory HTC reactor with an optical cell. The effect of reaction time was examined by altering it from 5 to 360 min at a constant temperature of 200 °C. It has been proven that hydrochar yields decrease and the heating value increases with an increase in reaction time from 5 to 360 min at 200 °C. The maximum higher heating value (20.41 MJ/kg) of hydrochar was obtained at 200 °C for 360 min. The highest degree of carbonization'of CS observed at 200 °C and a reaction time of 45 min and above. Furthermore, the experimental results were verified by mass and energy balances calculated with the simulation software IPSEpro. Based on these findings, a process sheet for an industrial application is suggested and calculated. • Hydrochar from cotton stalks was produced in a laboratory reactor with an optical cell. • The effects of reaction time on the energy and hydrochar yields were determined. • Cotton stalks HTC chars at 200 °C for 45 min and above are suitable for substituting peat. • Based on HTC simulation a process sheet for an industrial application was calculated. [ABSTRACT FROM AUTHOR]

• Hybrid bio-share energy systems offer a high potential associated with raw material price and conversion technology. • Waste biomass can significantly contribute to hybrid electrification. • A simulation tool using HOMER Pro-was successfully set-up and a mathematical model to calculate the range of system capacities. • An optimized system includes PV, biomass and grid connection. • PV module as well as biomass costs are the most sensitive parameters. Increasing household energy demand in the countries of the global south and the lack of conventional fuels and their high prices is forcing local authorities to look for alternatives. Based on the example of the city of Gaza, the primary renewable energy sources are large volumes of biomass, particularly waste-derived, which causes environmental and health damage, as well as abundant amounts of solar radiation. Hybrid renewable energy system (HRES) of solar and biomass is proposed, providing sustainable electrification for highly populated communities. By reviewing the literature studies on the electrification systems consisting of biomass and solar energy systems in the Middle East and North Africa (MENA) countries, and with respect to the corresponding technologies applied, we decided to incorporate a biogas engine generator. Simulation experiments are conducted by HOMER Pro-software of the residential district average daily demand is about 1074 kWh/day, and peaks of 84.5 kW p. The grid-connected system utilises renewable resources through photovoltaic panels and a biogas generator. Pre-mathematical model to evaluate the system components capacities is provided with different zones of load profile to achieve optimum solution of the biomass contribution and reveals at least $2.30 M net present cost (NPC) and $0. 438/kWh cost of energy (CoE). [ABSTRACT FROM AUTHOR]

Cotton stalks (CSs) are an abundant, renewable lignocellulose residue, which is usually burnt in the field to prevent propagation of vegetal diseases, causing economic losses and environmental concerns. The production of biogas has been considered as an alternative. This work aimed to improve the biogas production from CS by steam or organosolv plus supercritical carbon dioxide (scCO 2) pre-treatment. All samples were pre-treated in a 500 mL autoclave for 140 min at 180 °C and fermented in 1 L eudiometer batch digesters for 42 days at 37.5 °C. The biogas and methane yields achieved from the untreated CS were 250 and 137 norm litres per kg of volatile solid (L N kg−1 VS), respectively. Pre-treatment of the CS samples with steam or the organosolv plus scCO 2 process increased the methane yield by 20% compared to the untreated samples. The highest methane yield of 177 L N kg−1 VS was achieved by organosolv plus scCO 2 pre-treatment at 100 bar and 180 °C for 140 min. Moreover, pre-treatment of the CS led to a significant reduction in the optimal digestion time from 30 days to 20 days for biogas production for the untreated CS. • Cotton stalks successfully pre-treated for anaerobic digestion. • Organosolv followed by super-critical CO 2 pre-treatment increased methane yield. • Anaerobic digestion of pre-treated cotton stalks led to high quality biogas. • Significantly reduced retention time in the fermenter due to pre-treatment. [ABSTRACT FROM AUTHOR]

In the recent years Green to Green Energy Systems have gain tremendous interest because they are pollution free systems. In this frame, the present paper aims at investigating a Green to Green system coupling Photovoltaic, Wind and Fuel Cell. Furthermore, an analysis procedure is developed allowing to find the optimal configuration of coupling by assessing the output power in terms of the system parameters. Moreover, a case study on Lebanon is considered where three different regions that are Dahr El-Baidar, Klaiaat Akkar and Rayak Bekaa are studied. Results shows the flexibility and strength of the suggested procedure. Indeed, it has been shown that for Dahr El-Baidar it is suggested to adopt WFC system whereas for Klaiaat Akkar hybrid PVWFC is the optimal solution and PVFC is better for Rayak Bekaa. Furthermore, an economic based optimization is carried out. It was surprisingly found that from an economic standpoint and for a land area larger than 3000 m2 Rayak Bekaa is the optimal location for WFC hybrid system. • The work is performed within the frame of Green to Green (G2G) concept that combines green source to green storage. • Green sources are PV and Wind Turbine whereas the green storage system is fuel cell. • The developed model is applied to three different regions in Lebanon in order to find the best configuration. [ABSTRACT FROM AUTHOR]

Abstract Thermal conversion of ligno-cellulosic agricultural waste inside a pyrolysis reactor and soil-storage of pyrolysis char is discussed as a low-tech negative emission technology. Cotton stalks are a typical agricultural residue with little economic value and there is no direct competition to food or feed provision. Currently, the stalks are often burnt on the fields. The investigated rotary kiln pyrolysis process has already been successfully applied at industrial scale before. In the investigated scenario, the pyrolysis char is returned to the soil for long-term carbon storage while the volatile pyrolysis products are used energetically. The steady-state process simulation environment IPSEpro was used to assess a virtual conversion plant. The mass- and energy flows are determined based on earlier measurements at a 500 kg/h test plant. The results show that 52.8% of the carbon contained in the biomass accumulate in the biochar, whereas 38% of the input energy can be exported as heat energy at temperature levels suitable for electricity generation or industrial heat supply. The pyrolysis char shows a low molecular O/C ratio of 0.07 and an H/C ratio of 0.26. The expected half-lives of biochar in soil are in the order of 1000 years for O/C ratios below 0.2. This makes the presented approach an interesting low-tech negative emission option. The predicted net negative emissions through stored carbon amount to 2.42 t CO 2 per hectare and year. The overall CO 2 emission avoidance effect can be increased if fossil fuel is substituted by the energy exported from the pyrolysis process. Highlights • Low-value agricultural waste materials such as cotton stalks can serve as carbon precursor for negative emission solutions. • For slow pyrolysis of dry lingno-cellulosic material, roughly 53% of the carbon are found in the biochar product. • About 40% of the lower heating value-based energy in the feed biomass can be exported as heat. • The direct negative emissions through soil-storage of char from cotton stalks amount to 2.42 t CO 2 per hectare and year. [ABSTRACT FROM AUTHOR]