Last quarter HPNET Board of Representatives member Biraj Gautam described our project, shared about the development of a Turgo turbine design, appropriate for local manufacturing in Nepal.
While common in larger scale hydropower and with some off-the-shelf products available, the Turgo turbine is not currently manufactured by micro-hydropower companies in Nepal. As a medium head turbine, the Turgo offers a viable option for sites where the characteristics make the choice between Pelton and Cross-flow turbines difficult.
This article developed by Joe Butchers, PhD candidate at the University of Bristol, provides an update on our progress in the project so far.
While common in larger scale hydropower and with some off-the-shelf products available, the Turgo turbine is not currently manufactured by micro-hydropower companies in Nepal. As a medium head turbine, the Turgo offers a viable option for sites where the characteristics make the choice between Pelton and Cross-flow turbines difficult.
This article developed by Joe Butchers, PhD candidate at the University of Bristol, provides an update on our progress in the project so far.
 Fakfok MHP in Ilam, Nepal. An example of a medium head MHP, which could be appropriate for the Turgo turbine. Credit: Sam Williamson | Project Objectives An objective of the project was to install a micro-hydropower Turgo turbine at a pilot site. Currently, we have manufactured a 1.5kW Turgo turbine but it is important to check the performance of the turbine for higher rated powers. The experimental results from the 1.5kW turbine have allowed us to develop a hydrodynamic scaling model. This numerical model can be used to check whether a site has appropriate head and flow rate, and then determine the best pitch circle diameter and rotational speed for the turbine. |
After identifying a number of viable sites, we selected a site in Taplejung district where the existing turbine requires replacement after many years in service. For this site, our scaling model was used to show that the Turgo turbine is appropriate and can be used to directly drive a generator. Whilst similar to Pelton turbines, the higher specific speed of the Turgo means that direct drive transmission is feasible at much lower heads.
The different flow passages for the Pelton and Turgo turbines. Reference: P.N. Wilson, A high-speed impulse turbine, Water Power (1967)
Site Visit
Unfortunately, the ongoing coronavirus pandemic has prevented PEEDA staff from visiting the field site. A feasibility study is required to find out the technical and socio-economic features of the site and the community. Technically, we need to evaluate the current status of the civil structures and installed equipment. In addition, we require measurements of the powerhouse layout so that the new turbine can interface with existing components. From a socio-economic perspective, we want to understand how the plant is managed, whether the plant generates sufficient income, and assess the opportunity to maximise the plant’s capacity factor. It is important that we ensure that the plant is sustainable in delivering electricity to the community. We continue to monitor the coronavirus situation and hope to be able to visit the site when it is safe to do so.
3D CAD Design
Using the head and flow rate from the site and our scaling model, it has been possible to begin the detailed design of the Turgo turbine. The long-term intention is to develop a range of Turgo turbine designs appropriate for sites across the micro-hydropower range. We have been developing calculation sheets for all of the key components which allow dimensions to be determined. We have developed a parametric 3D CAD model that is linked to the calculation sheets. This allows us to quickly adapt the design depending on inputs into the calculation sheet. The 3D design is taking place collaboratively between the Electrical Energy Management Group at the University of Bristol and Nepal Yantra Shala Energy. The design objective is to produce a design that can be readily manufactured in Nepal with existing machinery and readily available materials. It is expected that detailed design will be completed soon allowing the production of engineering drawings to begin. Initially, the focus is on developing a complete design package for the site in Taplejung. This will include 2D engineering drawings, bill of materials, and supporting 3D CAD files allowing the design to be manufactured in Nepal. Subsequently, we will use the parametric 3D model to generate multiple design packages for the complete operational range.
Design of the Turgo runner in CAD software. Credit: Joe Butchers
March 2021 Workshop
Depending on coronavirus, we plan to hold a workshop in Nepal in late March 2021. The workshop will teach participants about the design packages, key stages in the manufacturing process, how to assemble and install the turbine, and about the operation and maintenance procedures. The workshop is intended for representatives of Nepali manufacturing companies but there may be several places available for international participants. In the longer term, we plan to make the completed design packages and the supporting materials available open-source online. We are hopeful that for local manufacturers across the Hydro Empowerment Network, we will be able to provide a design that increases their range of available turbine designs.
This article was written by Joe Butchers, PhD candidate at the University of Bristol. The project is titled Upscaling locally manufactured Turgo Turbine: Dissemination and Demonstration includes the Electrical Energy Management Group at the University of Bristol, PEEDA, Nepal Yantra Shala Energy, Turbine Testing Laboratory at Kathmandu University and HPNET as project partners, and is funded by Energize Nepal. The work undertaken by the University of Bristol is also funded through an EPSRC Impact Acceleration Account titled Development of an open-source Turgo turbine design tool.
