Research

Current Research

Feasibility study of photovoltaic power installation in rooftop of an educational institute

The renewable energy production continues to accelerate as the world recognizes the negative impact of fossil fuel consumption on the environment. Among the renewable energy technologies, there is rapid growth in the use of solar PV technology in past two decades. As solar PV technology has been widely used in providing green and sustainable energy from single household to different institution, educational institution currently attracted by this technology as it is economically competitive with other conventional forms of electricity generation. Hence, this study aims to design and accesses the potential of the grid connected solar PV system at rooftop of an educational institute building in Morang, Nepal. The monthly electricity consumption of the case study campus from 2018 to 2020 is taken through the electricity bills of Nepal Electricity Authority, Biratnagar Branch. The average daily solar irradiation is calculated for the roof top of the buildings of campus. After getting all the inputs, the system design and feasibility is conducted using tools PVSyst and PV*SOL. The performance of the system which can provide 100 % of energy need of the campus is simulated using PVSyst and the result were analyzed.

Publication in Prepration.

Evaluating Best Renewable Source for Jumla, Nepal using AHP

The percentage of the population remaining to get connected to electricity has decreased from 35 % to 4.5 % in this decade. However, 1.3 million out of 29 million Nepal’s population still need to be connected to an electricity supply. As most of this population lives in Karnali State, exploitation of renewable energy needs serious attention in this region as other energy sources are expensive and beyond reach. Choosing a suitable renewable energy technology that is economically feasible and environmentally acceptable is a topic of interest among researchers. Using one of the Decision Support systems helps in making easier choice for policy makers and government levels. In this case the research here-within evaluates among three renewable energy options, i.e. Micro-hydro, Solar Power and Wind power. The research shows that there Microhydro would be best suited option in case of Jumla.

Publication in preparation.

Past Research

Maximum power point tracker with solar prioritizer in photovoltaic application

The global use of solar photovoltaic system is accelerating rapidly due to the ever-decreasing cost and improvement on cell efficiency. The variation in solar irradiance, weather condition and temperature cause the non-linear output V-I characteristics of solar cell. To get maximum power from the solar array instantaneously, there is a need of an efficient maximum power point tracker. This study has implemented the incremental conductance MPPT algorithm in hardware and compared the result with software model using MATLAB/SIMULINK. This algorithm automatically changes duty cycle of the converter connected to the solar panel, so that the panel voltage becomes equal to the voltage equivalent to maximum power point at any level of insolation, temperature or load conditions. It is found that the software modeled MPPT algorithm increased the PV output by 38 % while it was 33% in hardware implementation. The prioritizer embedded in the system optimizes the use of solar power rather than utility grid.

Publication link : https://ieeexplore.ieee.org/abstract/document/7884494

Technical and economic prospects for the site implementation of a gravitational water vortex power plant in Nepal

Micro hydropower is a very promising renewable energy source for off-grid energy generation in remote areas where the resource exists. This study focuses on integrating an innovative new design of micro hydropower system called the Gravitational Water Vortex Power Plant into existing water infrastructure. Three types of existing water infrastructure are considered applicable for hydropower integration: irrigation canals, reservoirs and weirs. The theoretical designs for the civil works for the low-head gravitational water vortex power plant integrated into these structures are given and the costs of construction are estimated. A scalable system of 1.6kW is also designed and integrated in an existing irrigation canal for the technical performance evaluation and validate the theoretical economical study. The study concludes that the performance of turbine is mostly suitable for rural electrification and to integrate in cost-effective way, the civil works and installation cost should be greatly reduced.

Publication link : https://ieeexplore.ieee.org/abstract/document/7884485

Review of low head turbines system of Nepal for rural electrification

Small or micro hydro power generation is a promising renewable energy source that has received significant attention because of its capacity to generate green energy ranging from few watts up to hundreds of kilowatts. Small, low head hydropower plants are applicable in remote areas where grid extension is difficult due to geographical terrain. Micro hydro generators do not require the large cost of civil works for conventional hydropower and do not require the cost and environmental impacts of constructing a large dam and diversion structure. Recently there has been increasing interest in low head small hydro turbines by researchers and stakeholders who are working for rural electrification of off-grid communities in Nepal. This study discusses research and practice using various low head water micro hydro generators, including Improved Water Mills, Pico Hydro Generators, Gravitational Water Vortex Power Plants and Archimedes Screws, in Nepal. Major innovations with these systems by researchers working in Nepal are reviewed, and recent steps towards commercialization are discussed. The various technical and economic parameters of those systems are compared and evaluated. This information is essential for researchers and stakeholders to optimally select a suitable turbine according to site and economic conditions.

Publication Link: https://ieeexplore.ieee.org/abstract/document/8191182

Computational and Experimental Investigation of Runner for Gravitational Water Vortex Power Plant

The gravitational water vortex power plant (GWVPP) is a new type of low head turbine system in which a channel and basin structure is used to form a vortex, where the rotational energy from the water can be extracted through a runner. This study is focused on the optimization of the runner to improve the efficiency of the GWVPP. Computational fluid dynamics (CFD) analysis is carried out on three different runner designs with straight, twisted and curved blade profiles. ANSYS CFX was used to analyze the fluid flow through the channel, basin, turbine hub and blade, and results were used to evaluate the efficiency of each of the runner designs. The CFD analysis showed curved blade profile to be the most efficient profile, with a peak efficiency of 82%, compared to 46% for the straight blade runner and 63% for the twisted blade version. An experimental test of the turbine system was carried out to validate the runner analysis, in a scale version of the GWVPP. The testing showed that the runner behaved as predicted from the CFD analysis, and had a peak efficiency point of 71% at 0.5 m head.

Publication Link : Computational and Experimental Investigation of Runner for Gravitational Water Vortex Power Plant

Prospects of Off Grid Energy Generation through Low Head Screw Turbine in Nepal

Micro hydro power plants installed in Nepal are characterized with medium and high head, which are mainly available in Hilly region for off-grid energy generation. But the development of this kinds of system is very low due to difficulty in construction of civil components in the geographical structure. So this study focus on the prospects of the installation of a low head hydropower system i.e Arcemedian Screw Turbine which need very less civil construction works and has very low head requirement and medium to high discharge condition. In this study we show the comparative study of the various cost component of different micro hydropower system with Arcemedian Screw Turbine. In addition we also study the economic evaluation of integration of this system into existing water infrastructure. Two types of existing water infrastructure are considered applicable for hydropower integration: irrigation canals and reservoirs. The theoretical designs for the civil works for the low-head Arcemedian Screw Turbine integrated into these structures are given and the costs of construction are estimated. A fresh installation system data is also extracted from Alternative Energy Promotion Center, Nepal for comparison with existing water infrastructure installations. The study concludes that the performance of turbine is mostly suitable for rural electrification and to integrate in cost-effective way, the civil works and installation cost should be greatly reduced.

Publication link : https://ieeexplore.ieee.org/abstract/document/8566964

Performance analysis of Gravitational water vortex power plant using scale-down model

Gravitational water vortex power generation plant is ultra-low head micro hydro concept which requires mere 0.7-2m of height. GWVPP is based on the principle of power generation with rotation of turbine with the help of vortex generated due to basin structure when water can pass tangentially. This technology is in a primitive phase of development in various part of world. So, developers across the world are interested on how it performs in real site as only few real installations have been made far. This paper attempts to analyze the performance of different scale down model of GWVPP. First, the performance is compared among various experimental studies and pilot installations done so far in Nepal. After that the analysis of different computational studies is performed. To accesses the validation of the result obtained from the past researches, 1: 20 scale down model of a plant which is to be installed in Johannesburg South Africa is developed and whose computational and experimental result is compared and predicted the model performance.

Publication link : http://ttl.ku.edu.np/wp-content/uploads/2020/08/CRHTX-24-Ashish.pdf

Peer Reviewed Publication List

  1. Dhakal, R., Yadav, B. K., Koirala, N., Kumal, B., & Moussa, H. (2020). Feasibility study of distributed wind energy generation in Jumla Nepal. International Journal of Renewable Energy Research (IJRER), 10(3), 1501-1513. https://www.ijrer.org/ijrer/index.php/ijrer/article/view/11227 (Impact Factor 3.92)
  2. A Sedai, BK Yadav, BB Kumal, A Khatiwada, R Dhakal, 2020, Performance analysis of Gravitational water vortex power plant using scale-down model, Proceedings of the Current Research in Hydropower Technologies (CRHT X), Dhulikhel, Nepal, 28 April 2020.
  3. Dhakal, R., S. Dhakal, N. Koirala, S. C. Itani, S. Bhandari, G. B. Amgain, S. Bhatta, S. Gautam, and R. K. Shrestha. “Prospects of Off Grid Energy Generation through Low Head Screw Turbine in Nepal.” In 2018 7th International Conference on Renewable Energy Research and Applications (ICRERA), pp. 537-543. IEEE, 2018.
  4. Dhakal. R, Williamson. S.J, Khanal. K, Kumal. B, Bajracharya. TR, Shakya. SR, Gautam.S, Itani. S, Ghale. DP. 2017. Computational and Experimental Investigation of Turbine for Gravitational Water Vortex Power Plant. Proceeding of 6th International Conference on Renewable Energy Research and Applications, San Diego, USA. (Got best paper award)
  5. Koirala, N.Dhakal, R., Lubitz, D., Bhandari, S., Dev, G. P., Dhakal, Y., & Niraula, U. (2017, November). Review of low head turbines system of Nepal for rural electrification. In 2017 IEEE 6th International Conference on Renewable Energy Research and Applications (ICRERA) (pp. 861-869). IEEE.
  6. Gautam, S., Raut, D. B., Neupane, P., Ghale, D. P., & Dhakal, R. (2016, November). Maximum power point tracker with solar prioritizer in photovoltaic application. In 2016 IEEE International Conference on Renewable Energy Research and Applications (ICRERA) (pp. 1051-1054). IEEE.
  7. Dhakal, R., Williamson, S.J., Khanal, K., Acharya, A., Nepal, A., Aryal, T., Devkota, L., 2016. Technical and economical prospective for site implementation of low head gravitational water vortex power plant. 5thInternational Conference on Renewable Energy Research and Applications, Barmingham, UK.