Expert perspective on technological choice for cooking energy transition in Nepal

Solid biomass dominates as the primary source of cooking energy,especially in rural households of Nepal.The use of solid biomass has a detrimental effect on health,exacerbates the burden of biomass collection,and hampers access to clean energy.Understanding the factors influencing the choice of modern cooking fuels is crucial to improving energy security and resilience and easing the transition to clean fuels.This study evaluates technological choices for the transition in cooking energy from the perspective of experts working in the government,non-government,and academia sectors.A structured questionnaire survey was prepared with five criteria and nine cooking technology options.Fifty-one experts responded to the survey,and their responses were analyzed using the analytical hierarchy process.The study reveals that efficiency and capital cost are the primary criteria for selecting cooking technology.The most suitable clean cooking technology is an induction stove followed by a hot plate,while the least preferred technology is a Bayupankhi stove followed by two-pothole mud improved cooking stoves.To ensure the robustness of the method,sensitivity analysis was performed on the two primary criteria efficiency and capital cost of the cooking technology.The analysis revealed robust and consistent rankings of technologies.This study should help create a conducive environment for relevant stakeholders and policymakers to formulate and implement relevant policies and strategies to accelerate the cooking energy transition in Nepal.

CFD analysis for mixing performance of different types of household biodigesters

Household biodigesters are self-mixing anaerobic digesters used mostly in rural areas of developing countries as a reliable source of clean cooking energy.For an efficient anaerobic digestion process,the mixing of slurry inside the digester is regarded as one of the most important parameters.In this study,the mixing of slurry in three different designs of household digesters,namely the fixed-dome digester(GGC 2047 model),plug-flow digester and prefabricated plastic digester,are investigated and compared using compu-tational fluid dynamics.A 3D transient simulation is performed using a multiphase volume of fluid(VOF)model in Ansys^(■)Fluent release 16.0.The rheological properties of the feedstock are considered identical for all three digesters.The volume of the plug-flow and prefabricated plastic digesters is designed to be 1 m^(3) while the volume of the GGC 2047 digester was 6 m^(3) as the standard size of the household digester.The regions inside the digester where the velocity of slurry is<0.02 m/s are regarded as dead zones and the obtained results were analysed and compared using velocity patterns and dead-zone formation.It is found that the prefabricated plastic digester model has a relatively higher percentage of dead volume(74.6%)and the plug-flow digester has the lowest per-centage(54%)of dead volume among digesters that were compared in this study.The study will serve as the basis for designers and researchers to improve the design of household digesters for better mixing performances.

100% renewable energy with pumped-hydro-energy storage in Nepal

A radical transformation of the global energy system is underway.Solar photovoltaics and wind now comprise three-quarters of the global net new electricity-generation-capacity additions because they are cheap.The deep renewable electrification of energy services including transport,heating and industry will allow solar and wind to largely eliminate fossil fuels over the next few decades.This paper demonstrates that Nepal will be able to achieve energy self-sufficiency during the twenty-first century.Nepal has good solar and moderate hydroelectric potential but has negligible wind-and fossil-energy resources.The solar potential is about 100 times larger than that required to support a 100%solar-energy system in which all Nepalese citizens enjoy a similar per-person energy consumption to developed countries,without the use of fossil fuels and without the environmental degradation resulting from damming Nepal’s Himalayan rivers.Nepal has vast low-cost off-river pumped hydro-energy-storage potential,thus eliminating the need for on-river hydro storage and moderating the need for large-scale batteries.Solar,with support from hydro and battery storage,is likely to be the primary route for renewable electrification and rapid growth of the Nepalese energy system.

Cooking-energy transition in Nepal: trend review

Clean-cooking energy is key to meeting climate-mitigation goals and a range of development objectives,especially for improving the well-being of women and children.Inefficient burning of solid biomass for cooking releases household air pollution that is hazardous to health,while putting pressure on forest resources.This paper provides an overview of the household-cooking-energy transition in Nepal to date.Despite numerous efforts by the government and other actors to speed this transition,energy data spanning the years 2000-18 reveal that~69%of households nationwide still rely on solid fuels for cooking today.The proportion of solid-fuel users is especially high in rural regions,reaching>80%.Moreover,if the current rate of progress is not accelerated,the use of solid fuels will remain high even in 2030,preventing the achievement of Sustainable Development Goal(SDG)7.Cooking-fuel choices are heavily constrained by accessibility,demographic and socio-economic factors.Thus,this paper recommends that evidence-based and integrated policies and strategies be urgently deployed to foster a more effective and rapid transition towards clean energy,which is critical to achieving SDG 7.