Refurbishment |
trained operators, affecting the provision of spare parts, and reducing the opportunity for income generation. In plant renovation, the authors caution, these pre- existing challenges should not be overlooked. The option of renovation and repowering a site offers the opportunity to install new turbine designs to improve the performance. As the authors explain, historically across Nepal there have been only two micro-hydropower turbine designs that are locally manufactured - the Crossflow and the Pelton which were both introduced by international development agencies. Over the past ten years though, three additional designs have been developed that can also be manufactured locally - a propeller turbine, Francis turbine and Turgo turbine. “The Turgo turbine is especially interesting, as it can easily be retrofitted into existing infrastructure with minimal adaptation for both Pelton and Crossflow sites. Furthermore,” Butchers et al say, “it can bridge between the typical operational ranges of the Pelton and Crossflow.” In their research, the authors investigate the use of
Above: Front pages of the newspapers the day after an earthquake struck Nepal in April 2015. More than 260 micro hydropower plants were damaged as a result © Anelovski /
Shutterstock.com
removal is an improvement over other remediation methods that tended to be used in the SRC, such as retain weirs and construct fish passes built alongside them. A nod of acknowledgement was also given to heritage values that some individuals hold for weirs, as a lot of weirs across the catchment have links to an industrial heritage. In addition the research pointed towards the need
for greater collaboration, and more learning, sharing, and building on the successes in the SRC, and in other catchments and countries. As one respondent remarked: “it always feels with fish pass work that every country is kind of siloed and doing its own thing, like the French do their thing their way, the Germans do their thing their way, we do our thing our way, the Americans do their thing their way, and […] there isn’t a great deal of learning from one another”.
Challenges and opportunities There are many challenges but also opportunities
when considering renovating existing micro- hydropower sites around the world, as demonstrated by recent work in Nepal. The 2015 earthquake that wreaked havoc across the country damaged an estimated 262 micro hydropower plants in the districts surrounding the earthquake’s epicentre, impacting over 37,000 households. Small- scale natural disasters are also prevalent in Nepal, such as landslides, flooding and avalanches, and these can often affect plants due to their location in the base of valleys near water courses. Even without extreme events, commissioned sites often do not last as long as their expected 50-year lifespan, and can fail for many reasons but generally due to poor maintenance. As Joe Butchers et al explain in research published in the Journal of Sustainable Research, such failures provide an opportunity to renovate, refurbish and upgrade hydropower sites, using updated designs and technology to provide an improved service to the community. However, the remote location of sites across Nepal can have an impact, such as reducing the availability of
24 | September 2024 |
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a Turgo turbine for the renovation an existing micro hydropower installation site in Nepal. They focused on the 27kW Mangmaya Khola plant in Sangu, Taplejung district which was built in 2005. Over time, the power output of the plant had reduced to about 18kW due to leaking of the existing turbine and possible erosion of the existing Crossflow turbine blades. After the installation and commissioning of the
Turgo turbine at the plant, power output was increased to 32kW due to increased efficiency of the Turgo system over the Crossflow at the rated conditions. As the authors reported: “The potential benefits
of renovating existing sites are many, but in terms of increased power outputs, higher efficiencies and plant reliability, the options around utilising modern turbine designs in particular are essential in order to achieve higher performance at investment and operating costs which are economically viable over the plant’s lifetime.” However, after operating for only 18 months, the
refurbished Mangmaya Khola plant was badly affected by a landslide in the local area in July 2023. The penstock and powerhouse were severely damaged and Nepali project partners are exploring how it can be restored to operation.
As mentioned in their paper, Butchers et al say the incident further demonstrates the risk that landslides pose to micro hydropower plants in Nepal.
References
When unlocking rivers results in building more infrastructure: A group mental model shares lessons from weir remediation in the United Kingdom by Stephanie R. Januchowski-Hartley, Merryn Thomas, Rochelle Bristol, Morena Mills. Conservation Science and Practice. 2024;6:e13081 Volume 6, Issue 3
https://doi.org/10.1111/csp2.13081
A Methodology for Renovation of MicroHydropower Plants: A Case Study Using a Turgo Turbine in Nepal by Joe Butchers, Sam Williamson, Julian Booker, Suman Raj Pradhan, Prem Bikram Karki, Biraj Gautam, Bikram Raj Pradhan, and Prajwal Sapkota. J Sustain Res. 2023;5(4):e230015.
https://doi.org/10.20900/jsr20230015
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