Understanding sustainable operation of micro-hydropower:a field study in Nepal

Off-grid renewable energy technologies are important in improving electricity access for rural communities. However, methods for ensuring their sustainable operation are often poorly understood. In this article, existing approaches for the assessment of off-grid projects are examined. Reliability of the technology, financial viability and community engagement are identified as the 3 key areas governing the sustainability of projects. Focusing on these areas, a methodology is proposed to understand the sustainability of micro-hydropower plants. A mixed-methods approach including a maintenance assessment and interviews with managers, operators and consumers is used to evaluate 24 sites in Nepal. Technically, the results of the study showed that trained operators delivered a higher standard of maintenance, however, technical issues were identified that arise during the design, manufacture and installation phases. The financial viability of plants was aided by charging consumers based on consumption, whilst plants with a higher rated capacity tended to benefit from a larger number of productive end uses. Community engagement was fostered through the local identity of the plant however this was threatened by societal changes. Inherent features of the site, such as rated power and the population density, internal resilience to short-term shock events (failure of components, insufficient collection of tariffs and departure of trained operators) and long-term external development (increased incomes, increased energy consumptions and growth in rural settlements) were found to affect the sustainability of plants

Cost estimation of micro-hydropower equipment in Nepal

Selecting the appropriate technology for providing electricity to rural communities depends upon evaluating the cost of a potential installation. For some rural communities, locally manufactured technology, in the form of wind and hydropower, can be effective. However, often the cost of these locally manufactured technologies is largely unknown. Access to costing data allows the economic viability of a site to be compared with other options. Furthermore, it enables benchmarking, allowing the expected total cost of an installation, or individual sub-systems, to be compared with quotations. This paper attempts to address the current lack of publicly available costing information for locally manufactured micro-hydropower equipment. A methodology is presented where quotations are provided by micro-hydropower manufacturing companies in Nepal for randomly generated sites. Using that information, they provided a quotation for various sub-systems. This data allows comparison of the cost of major components and the influence of turbine type. Through a linear regression model, expression have been developed that can be used to determine the expected cost for both Pelton and Crossflow turbine installations. The accuracy of these expressions is compared with previous costing models, the outcomes of the work and their significance in the context of Nepal and elsewhere is discussed. The key contribution of this work is establishing numerical expressions which allow proposed costs of micro-hydropower equipment to be rapidly evaluated

A methodology for renovation of micro-hydropower plants: A case study using a turgo turbine in Nepal

For off-grid communities, micro-hydropower continues to provide affordable and reliable electricity access across the world. In Nepal, despite ongoing development of large-scale hydropower projects and the extension of the national grid, there remain many off-grid communities that depend on micro-hydropower plants. Over time, these systems are prone to erosion from sediment in the water, which, together with other degrading mechanical and environmental effects, may lead to reduced reliability and potential failure. Extreme weather and natural disasters can also cause catastrophic failure of the plant and its infrastructure. In such cases, Nepali micro-hydropower companies are best placed to conduct renovation works.Where renovation is required, the selection of a different turbine type could be beneficial. Recent work has demonstrated the potential of the Turgo turbine for use in Nepal due to several advantageous features. In this paper, a methodology is applied to explore the feasibility of a site for refurbishment considering environmental, social, technical, economic, and legal factors. Subsequently, a series of design and costing activities are used to demonstrate that the Turgo turbine can be implemented. A Turgo turbine design is scaled appropriately and manufactured by a Nepali company. The turbine demonstrated an increase in power generated, from 18 kW for the existing turbine to 32 kW for the newly installed turbine. The potential for Turgo turbines at other sites around Nepal is analysed, demonstrating it could be used to renovate and improve energy production at many sites across the country