Journal of Renewable Energy and Environment
Volume:10 Issue: 1, Winter 2023

Reducing the demand for fossil fuels and the derived products can be achieved through the development of alternative energy sources. This work presents a countrywide study of the energy potential of lignocellulosic biomass sourced from agro-industrial by-products in the country of Peru. Ranking of the crops that produce the most waste was followed by an energy potential evaluation of carbohydrate conversion and thermochemical conversion. The crops with high calorific values were sugar cane bagasse, wood waste, and coffee husk. The energy potential of the principal lignocellulosic by-products, in terms of tons of oil equivalents per year, resulted from rice straw at 1.45 M, followed by corn residue at 1.13 M and sugar cane residue at 1.10 M. The northern region of Peru generated the highest quantities of rice (straw and husk), banana (husk and rachis), and sugar cane (bagasse and straw) by-products and the southern regions generated the greatest quantities of quinoa residue, all of which could be used as raw materials for biofuels and aggregates for materials. These results indicate that theoretically, this readily available biomass could meet the country's energy demands while promoting sustainability and national energy security.

In the power system, frequency stability is critical. The wind turbine oscillates (depending on the wind speed) and is of low inertia. Thus, wind turbines face the issue of power system frequency stability. Since the power system's resources are interconnected via communication networks, the presence of time delay also affects the frequency stability of the power system. When a disturbance occurs in the power system due to load or distributed generation sources (wind turbine), it leads to frequency deviations in the power system, exhibiting low damping speed. Although large conventional generators in the power system provide sufficient inertia and reduce frequency deviation, the damping speed of frequency fluctuations is slow, which may be due to time delays between power system resources. In this paper, virtual damping (a proposed method) is used to accelerate the damping of frequency deviations caused by load disturbances, distributed generation source disturbances, and the time delay between power system resources. The results of the proposed method are compared to those obtained using the conventional method in this field, demonstrating the superiority of the proposed method. The proposed method reduced frequency deviations in the power system caused by disturbances and time delays by 67 % (a 67 % improvement over existing methods in this field) and increased the damping speed of the frequency deviations by 62 % (a 62 % improvement over the methods used in this field).

Increased global energy consumption demands the use of more energy resources, aggravating environmental issues. This study focused on analyzing biogas production from a mixture of cow dung, water hyacinth, and food waste and checking the efficiency of the biogas. The efficiency of biogas production was tested using two alternative settings in the study. The first setup employs Eichhornia crassipes that have been NaOH-treated and mixed with co-digestion substrates such as cow manure and food waste which have been stored at room temperature for 32 days. The second setup contains five different types of substrates such as L1-cow dung, L2- cow dung: water hyacinth, L3-cow dung: food waste, L4-cow dung: water hyacinth: food waste, and L5-water hyacinth. The properties of the Eichhornia crassipes were studied on several biogas substrates, such as pH, temperature, COD, TOC, and NPK tests, as well as total biogas output and methane percentage. The results of the comparison analysis show that the substrate L4 has a high level of NPK (4.7 %) and a higher amount of COD (137600 mg/l). These characteristics enhance the gas yield and methane percentage (85 %). Overall, the water hyacinth mixed with cow dung and food waste exceeded the other four substrates. The total yield of biogas from the first setup was 8.5 litres, the flammability was tested on the 28th day, and the blue flame was obtained. Water hyacinth was removed from aquatic areas and used as an alternative energy source, hence being environmentally friendly.

Briquettes from agro-residues have been promoted as a better replacement to firewood and charcoals for heating and cooking in the rural communities. In view of this, a study was carried out to investigate the effect of pretreatment methods on physical properties and heating values of briquettes produced from corncob. To accomplish this work, the experiment was designed as a 2×3×3×3 completely randomized with three replicates. The parameters are pretreatment methods (carbonized and uncarbonized), binder types (cassava, corn and gelatine), binder concentrations (10, 20, 30%) and compacting pressure (50, 100 and 150 kPa). A charcoal kiln was fabricated to obtain the pretreatment through pyrolysis and a punch and die was also fabricated to enable the briquette densification. The physical properties tested were limited to moisture content (MC), density and compressive strength and were determined using a conventional method. The heating value of the briquettes produced was determined using bomb calorimeter. The results showed that average moisture content ranged between 5.29-6.58% and 12.75-13.72%, mean relaxed density varied from 813-925 kgm-3 and 963-1166 kgm-3, compressive strength ranged between 2.27-5.07 MPa and 5.97-10.12 MPa and heating value ranged between 28.85-32.36 MJkg-1 and 27.58-28.80 MJkg-1 for carbonized and uncarbonized briquettes, respectively. Briquettes produced from carbonized corncob had a better moisture content and heating value, while briquettes produced from uncarbonized corncob had higher density and compressive strength. The study shows that pretreatment methods under different binder types and concentrations and the compacting pressure significantly affected briquette’s physical properties and heating values.

This study aims to assess the potential of coupling solar PV power plants with Battery Energy Storage System (BESS) to curtail load-shedding and provide a stable and reliable baseload power generation in Zimbabwe. Data from geographical surveys, power plant proposals, and investment information from related sources were reviewed and applied accordingly. Areas considered to be of good potential to employ the use of BESS were identified considering such factors as feasibility of PV plants, proximity to transmission lines, the size of a town or neighborhood, and energy demands for BESS Return On Investment (ROI) calculations. Previous studies have proven that 10% of the suitable land for PV systems has the capability to generate thirty times the current power demand of the nation operating even with the least efficiency. In recent years, coupling renewable energy sources with a suitable energy storage system yielded improved performances, giving consumers a reliable, stable, and predictable grid. BESS technologies on the utility scale have improved in recent years, giving more options with improved safety, and decreasing the purchase costs, too.

Distributed flexible ac transmission system (D-FACTS) is a light-weight version of FACTS, which it is easily allocated and costs less than flexible ac transmission system (FACTS) devices. They have potential benefits to improve the system stability and improvement in power quality in microgrid (MG). The integration of distributed energy sources, loads, electrical energy storage devices, and electronic power devices, as well as the operation of microgrids in connected or island-connected modes has expanded their use. It is a small main grid that can generate electricity when disconnected from the main network. In addition, microgrids reduce the high investment costs required to upgrade the network. The application of DFACTS devices for improving the microgrid operation has been investigated by some researches. This paper provides a review of impact and role of various DFACTS devices in the function of microgrids, which has been reported in recent years in various pieces of the literature. DFACTS devices with their properties are described. Finally, a useful reference and framework for the study is provided for future expansion of DFACTS devices so as to improve the performance of the microgrid.

Energy harvesting from ambient vibrations using piezoelectric cantilevers is one of the most popular mechanisms for producing electrical energy. Recently, efforts have been made to improve the performance of energy harvesters. The output voltage dramatically depends on the geometrical and physical parameters of these devices. In addition, improved performance is often achieved by operating at or near the resonance point. So, this paper aims to reduce the natural frequency to match the environmental excitation frequency and increase the harvested energy. For this purpose, different geometrical and physical parameters are studied to determine the impact of each parameter. These parameters include the length, thickness, density, and Young’s modulus of each layer. The beam is considered a unimorph cantilever with rectangular configuration and the study is performed using COMSOL Multiphysics software. The results are compared with those obtained by an analytical approach. The results show that changing the parameters made the natural frequency of the system vary in the range of 20 Hz to 200 Hz and increased the output voltage up to 20 V.

In this study, various configurations design of a Heat Recovery Steam Generator (HRSG) are examined to enhance energy efficiency of a Combined Cycle Power Plant (CCPP). A novel approach is used to investigate ten applicable configurations of a dual pressure Heat Recovery Steam Generator HRSG thoroughly to explore the best practice models from the energy-conserving considerations. Further, a fuel consumption assessment has been conducted to identify the best performance of the cycle and investigate the minimum pollutants released of each Heat Recovery Steam Generator (HRSG) configuration. The results have revealed that four scenarios among ten, have expressed a considerably better performance regarding; fuel consumption, steam production, energy efficiency, and finally yet importantly environmental considerations. Further, it has been found that in comparison to the conventional configuration, not only the selected scenarios have proved almost four times improvement in the low-pressure steam generation, but also 30% fuel consumption saving in supplementary firing has been achieved which has both economic and environmental benefits. Moreover the carbon dioxide saving potential for the best scenario is 51.37 kgCO2 MWh-1 consequently the environmental benefit of it is calculated about 133,418 $ MWh-1.