Abstract
As the world is facing the effects of global warming and climate change, it has become an enormous priority to tackle those impacts. Since the world is heavily dependent on fossil fuels ...which are the major contributor of carbon, trying to find an alternative for a carbon-free future without disrupting the energy balance is a treacherous task. Green Hydrogen produced via electrolysis from renewable electricity can be a game changer in the future. Electrolysis is done by a device called electrolyzer and Proton Exchange Membrane Water Electrolyzers (PEMWE) have been touted as the most prevalent. In this review paper, the very basics of PEMWE will be discussed and then delve into the key components of PEMWE where materials, a few research, challenges, and then future suggestions will be delivered.
Pumps are the mechanical device used to increase the pressure energy of fluids. Pumps of different types and size are being used in Nepal, for different applications. Despite the wide spread ...applications of pumps not much have been done to manufacture pumps in Nepal. This study investigates the opportunity of manufacturing pumps in Nepal. It shows the history of usage of pumps in Nepal and also depicts the problems faced by the pumps used in different projects. It discusses about the current market trend related to the import of pumps from foreign countries and develops an argument to start a new business for manufacturing pumps. Role of research institutes like Turbine Testing Laboratory in design of pumps has been discussed as a future prospect for Nepalese academia and industry.
Sediment erosion in hydraulic turbines has been a major challenge in development of hydropower projects in Nepal. The hard abrasive material present in the river water of this region cause rapid ...erosion of turbine components and affect the performance of turbines, which in turn decreases the efficiency, reliability and operating life of such projects. There is a need of a new design methodology to develop turbines to resist erosion in high sediment conditions. The first step towards such development would be to investigate different design options in laboratory, which needs a standard methodology to carry out sediment erosion test in controlled environment. This study is focused on design and development of a laboratory test setup suitable for carrying out sediment erosion test in Francis runner blades. A test rig called rotating disc apparatus has been developed and installed in Turbine Testing Laboratory, Kathmandu University, Nepal, which uses Francis runner blades as test specimens. The test carried out in this setup has shown that the Francis turbines designed with traditional design methodology is highly prone to loss of material due to sediment erosion.
•Rotating disc apparatus is developed for sediment erosion test in Francis blades.•Francis runner blades designed by traditional methodology are used as test specimens.•Erosion pattern observed is similar to that observed in real hydropower plant.•Erosion pattern is similar to that predicted from CFD analysis in earlier studies.•Traditional designs of Francis turbines are highly prone to sediment damages.
Sediment erosion is a major problem in hydropower plants of Himalayan and Andes region which causes frequent breakdown of electromechanical parts in contact with sediment laden water demanding ...regular maintenance. Sediment suspended in water with high velocity has higher potential to erosion of the turbine parts. Studies show that sediment erosion can be minimized to some extent if modifications in the design, use of erosion resistant material as well as application of erosion resistant paints are carried out on those components. Besides, thorough understanding of sediment by proper analysis is important for designing and making components less prone to sediment erosion. The efficiency of sediment analysis depends on the sampling method and the method used for particle size distribution (PSD) analysis and mineral content (MC) analysis. Depending on the nature of the stream, a different method should be adopted. This paper presents a general overview of the method of sampling, method of PSD and MC analysis.
Abstract
Process heating is an important step in manufacturing industries such as metal, cement, brick, food, etc., and accounts for a large share of the total energy consumption of those industries. ...In Nepal, process heating alone accounts for around 64% of the process energy of the manufacturing sector. Around 64% of Nepalese industries’ energy demand for process heating is supplied by high-carbon emitting fossil fuels such as coal, diesel, etc. The industrial sector is responsible for significant global greenhouse gas emissions. Nepalese manufacturing Industries emit around 0.002248 GT of CO
2
annually. The movement toward carbon neutrality has prompted many countries around the world to look for clean and sustainable fuel to meet their decarbonization goal. This study overviews Nepalese industries’ different industrial heating processes in terms of energy consumption, emissions, energy efficiency measures and interventions, and renewable options from a literature review and using data from secondary sources. Based on the data collected and the literature review of the industries, the potential low-carbon fuels which can be compatible with heating applications in Nepalese industries are reviewed. This paper concludes with recommendations for the future decarbonization of process heating in Nepalese industries.
Despite the initiation of the master plan, envisioned by the government of Nepal, complete electrification of rural Nepal still seems over ambitious for quite a long time. Thus Micro Hydropower ...Plants (MHP) can still be very effective for rural electrification. Decades of manufacturing of same type turbines have saturated the turbine manufacturing industries of Nepal, which demands for some new innovations and that could be the introduction of Francis turbine in Nepalese MHP. It's undeniable that there are umpteen opportunities for the turbine manufacturers to manufacture and install the Francis turbines in Nepalese MHP. The feasibility studies performed by different institutions and the government policy strengthen the claim. In addition to that, data received from, NMHDA and a local turbine manufacturing industry suggest that there are abundant sites suitable for installation of Francis turbine. This paper illustrates the need of introducing the Francis turbine in Nepalese MHP and discusses about the opportunities available for the turbine manufacturers to enter into the market of Francis turbines for micro hydro and subsequently for larger hydropower projects in the near future. The challenges associated with the introduction of Francis turbine in MHP are highlighted.
Abstract
The global transition from carbon-based fuel to cleaner energy sources has brought an application of hydrogen as fuel in multiple hybrid applications from backup power to onboard power ...sources, especially in the automobile industry. The application in the fuel cell hybrid system brings the integration of fuel cells with Lithium-Ion batteries and ultracapacitors. The efficient and reliable operation of the vehicle drivetrain highly depends on the power control mechanisms integrated with the system. Power converters play a significant role in converting the DC to DC or AC and AC to DC which maintains the power supply driving the hybrid power transmission system and other vehicle auxiliary loads. Fuel cell vehicles require high efficiency of the converters to optimize fuel consumption in various operating conditions. The paper introduces various topologies of Power electronic converters used in hybrid applications along with their pros and cons in various switching techniques adopted. The different power electronic converters are modeled in MATLAB-SIMULINK and comparative analysis has been performed to improve the efficiency and reliability of the system.
Abstract
Electricity backup systems are needed to address the temporary grid failure, short-term electricity supply at the locations without grids, power surges, and massive blackouts. These power ...backup technologies include a combination of batteries and generators operating mostly on fossil fuels. Concerns regarding instant start capability with generators, noise, and mainly due to carbon emissions have encouraged to look for alternatives with low carbon technologies based on renewable energy sources. Stored electricity from solar, wind and other renewable sources are emerging and cost-competitive alternatives to fossil fuels-based power backup systems. Due to the high energy density, unlimited production source, and easy storage and transportation, hydrogen is emerging as an effective and efficient energy carrier and its applications for an alternative to power supply systems. Hydrogen produced from the electrolysis of water by renewable electricity makes it green and has minimum carbon emissions among the other alternatives and operates in real-time startups with no mechanical noise.
Fuel cell is a growing technology and has the potential to channelize hydrogen energy as an alternative to carbon-intensive power supply systems. In a fuel cell, hydrogen combines with oxygen and produces electricity. The fuel cell is a robust design with several parameters that control its operation and capacity. This paper identifies the parameter-based modeling approach to establish a connection of power demand with hydrogen production. A mathematical model for system sizing of hydrogen production and fuel cell for re-electrification for a reference case is developed.
Abstract
The national grid of Nepal faces several hurdles during its operation, especially in remote areas of hilly and mountain region. Citizens face blackouts of days to weeks, due disturbances ...caused in the grid in those regions. Micro hydro can be a very strategic backup for the national grid in those regions. However, due to lack of subsidy, which used to be provided in the past, for development of micro hydro, micro developers are unable to afford the construction cost of the micro hydro. Thus using Pumps that are readily available in the market at a much cheaper price, compared to custom built hydro turbines, as turbines can be a very economical alternative for such cases. But the concept of pump as turbine has not been utilized in Nepalese market. In this study, a centrifugal pump abundantly available in the Nepalese market has been used to evaluate its performance in turbine mode as well as in pump mode. A characteristic performance curve of the pump operated in turbine mode is obtained from the experimental data. The Best efficiency point and the operating regime is also determined based on the results obtained from experiments. The head conversion factor and discharge conversion factor calculated based on the data measured from the experiment, at various operating conditions, are compared to previous works done by other researchers. The performance obtained from the experimental analysis is comparable to the performance of the turbines installed in the micro hydro power projects. PAT can be a game changer in the micro hydro sector, by providing a very economical and technically viable option of expensive hydro turbines.
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