• Energy Research

Abstract Large quantity of animal waste production in Bangladesh has spurred the demand of potential applications for waste management. Therefore, biofuel production from animal waste has been projected as the solution for animal waste management along with the potential of a new source of renewable energy. This study aimed to evaluate the production of biogas from the farm wastes in Bangladesh and presented the potential biological applications for processing the wastes to convert into biogas. The study demonstrated that the highest amount of livestock waste, approximately 229 million ton was produced in 2016 and it was accounted for a total biogas production potential of 16988.97 million m3 which could be converted into 16.68 × 107 MWh of electricity. This study also presented the suitable conversion technologies as well as mechanisms of biogas production from animal waste and related mathematical equations to calculate the amount of total biogas productions. The latest advancements in large scale biogas production via government and non-government organizations have also been documented in this work. Besides biogas production analysis, this study also demonstrated the environmental impacts of biogas application. A net CO2 emission reduction of 4.42 million tons could have been achieved over the diesel power generation along with 29 million ton of biofertilizer. The study also proposed a management plan to improve the current waste removal situation in Bangladesh. Along with that, this review comprehensively outlined the worldwide scenario of biogas production and applications.

Abstract In this paper, energy, exergy, and sustainability analyses are done for the residential sector of Bangladesh based on statistics from 2000 to 2015. The purpose is to gain a deep understanding and pragmatic perception of this sector’s energy consumption. It is found that the energy efficiency varies between 25.54% and 37.77% while the exergy efficiency varies between 6.35% and 9.04%. In order to address the sustainability of this sector several indicators such as depletion number, sustainability index, lack of productivity, relative irreversibility, renewable share, non-renewable share, waste exergy ratio, and environmental effect factor are used. Depletion number varies between 0.91 and 0.94 while sustainability index varies between 1.06 and 1.11. The high rate of depletion of fossil fuels has contributed to a lower value of sustainability index. Among various types of fossil fuel consumed in this sector, both energy and exergy from biofuel is higher, and this is validated from high values obtained for the used indicators. For biofuel, the maximum relative irreversibility is found to be 0.83 and maximum lack of productivity is 12.19. To ensure sustainability and to reduce environmental impact from this sector, it is recommended to introduce sustainable cooking technologies in the rural sector.

Banana stem is being considered as the second largest waste biomass in Malaysia. Therefore, the environmental challenge of managing this huge amount of biomass as well as converting the feedstock into value-added products has spurred the demand for diversified applications to be implemented as a realistic approach. In this study, banana stem waste was experimented for bioethanol generation via hydrolysis and fermentation methods with the presence of Saccharomyces cerevisiae (yeast) subsequently. Along with the experimental analysis, a realistic pilot scale application of electricity generation from the bioethanol has been designed by HOMER software to demonstrate techno-economic and environmental impact. During sulfuric acid and enzymatic hydrolysis, the highest glucose yield was 5.614 and 40.61 g/L, respectively. During fermentation, the maximum and minimum glucose yield was 62.23 g/L at 12 h and 0.69 g/L at 72 h, respectively. Subsequently, 99.8% pure bioethanol was recovered by a distillation process. Plant modeling simulated operating costs 65,980 US$/y, net production cost 869347 US$ and electricity cost 0.392 US$/kWh. The CO2 emission from bioethanol was 97,161 kg/y and SO2 emission was 513 kg/y which is much lower than diesel emission. The overall bioethanol production from banana stem and application of electricity generation presented the approach economically favorable and environmentally benign.

AbstractTransportation sector is one of the core parts of modern civilization. Proper utilization of energy and exergy in this sector is necessary to ensure energy loss and environmental sustainability. Increasing exergy efficiency will reduce carbon emissions from this sector. Since 1970, Reistad estimates have been widely used to determine the energy and exergy efficiencies of this sector. However, the modern transport sector has undergone significant changes in recent decades. Hence, it is necessary to apply new Reistad estimates in determining the energy and exergy efficiencies. This is the first study to apply updated Reistad estimates to explore the energy and exergy efficiencies in the transportation sector of Bangladesh based on the data from 2000 to 2017. The overall exergy efficiency is significantly lower than the energy efficiencies as it ranges from 27.7% to 30.0%. Efficiencies are lower as the maximum portion of input exergy is lost to the environment. The road subsector needs major improvements as it is responsible for major amount of exergy loss. A comparison is made between conventional and updated estimates which highlights that the updated estimates provide more accurate results. Thus, it is recommended to apply updated Reistad estimates in determining the energy and exergy efficiencies of the transport sector.

Climate change and the associated global warming raise the possibility of weather-related natural disasters. Power outages due to natural catastrophes cause substantial financial loss. Moreover, an uninterrupted power supply is essential in disaster-prone areas to continue rescue and other humanitarian activities. Therefore, energy systems must be resilient to withstand power outages due to natural events. Resilience and enhancement techniques, and schemes of integrated electricity and microgrids’ heat demand during power outages, were mainly overlooked in the earlier analysis. Therefore, this analysis aims to analyze a grid-tied microgrid’s survivability during a power outage due to a natural disaster in Texas, USA. Mixed-integer linear programming (MILP) is used to optimize various energy resources, such as PV, battery, grid, and combined heat and power (CHP) for Texas, USA. These technologies were run in an outage condition to observe their resiliency benefits. To determine the resilience performance of the CHP/PV/battery system for the hospital building, a new probabilistic approach was applied. A 24-h outage was simulated in REopt lite software, and this study found that the PV/battery/CHP system could easily withstand the outage. The optimum system consists of 3933 kW of PV, 4441 kWh of storage, and a CHP unit having a capacity of 208 kW. The proposed microgrid emits 79.81% less CO2 than the only grid system. The microgrid has a net benefit of $1,007,204 over the project duration. The introduction of the proposed microgrid will bring about life-cycle savings (LCS) of 37.02 million USD over the project’s lifespan.

Abstract During this industrialized era, consumption of high-speed diesel (HSD) is increasing rapidly in the power, transportation, agriculture, and other commercial sectors of Bangladesh, albeit a significant amount of HSD is imported from foreign countries. The fuel mono-dependency on imported HSD demands huge economic investment of any country that consequences a negative impact on the cash flow of the overall economy. This study emphasized the contribution of HSD from petroleum products in significant fields and provided the current scenario of diesel import. Besides fuel issues, the other major environmental concern of Bangladesh is tremendous carbon emission caused by the overuse of diesel that consequences severe environmental pollution. To minimize the investment in imported HSD as well as environmental pollution, an alternative fuel, biodiesel generation, has been proposed in this study. This study also projected the total approximate biodiesel production from chicken skin collected from the whole of Bangladesh. Besides, this study also predicted the possible amount of can be replaced by biodiesel from chicken skin and aimed at the cost reduction due to the replacement of diesel by biodiesel.

Worldwide, health care sectors are experiencing massive pressure due to the emergence of COVID-19. Many temporary health care centers have been set up to treat infected patients. Increasing energy consumption in these centers is responsible for both rising energy demand and emission. Implementation of renewable energy-based hybrid stone-alone systems can play a vital role in optimizing increasing energy demand. The aim of this analysis is to design a stand-alone system for a temporary health care center located in Saint Martin Island, Bangladesh. This is the first study which highlights the power management of a hospital load. Homer Pro software is used to design the preliminary model, and the proposed configuration comprises PV/Converter/WIND/Battery/Generator. It is observed that the Levelized cost of the proposed system is $0.4688. This system's Levelized cost of energy (LCOE) is 35% lower than the solar home system (SHS). The payback period (PB), rate of investment (ROI), and internal rate of return (IROR) of the optimized system are seven years, 10, and 13%, respectively. The proposed configuration is environmentally sustainable as it generates 27% less CO(2) than a diesel-based fuel system.