Modular Fish Ladders for Small-scale Hydropower Plants in Sweden

Abstract

In this master thesis, new modular principles for upstream fish passages at small-scale hydroelectric power plants in Sweden are investigated. The product development study is conducted at Chalmers University of Technology and carried out in collaboration with The Hydroelectric Environmental Fund (Vattenkraftens Miljöfond Sverige AB). The initial motivation behind the study was the anticipated increase of fish passages that are to be built in the coming years, as a result of modifications to the Environmental Code. In the initial problem identification, the costs associated with fish passages emerged as the most tangible problem for small-scale hydropower plant owners. Since pre-construction work and customised design based on local conditions were identified as crucial cost parameters, a space efficient solution that was based on a spiral shaped design with mass-produced modules was justified. The study thus aimed to pre-develop these modules with respect to stakeholders' expectations, needs and requirements and in relation to material selection and choice of production technique. Findings from extensive exploration, including site visits, interviews and literature review, could be summarised in a stakeholder analysis. Besides cost-efficiency, and the obvious need of excellent passage efficiency, the importance of maintenance and environmental sustainability emerged as significant factors, guiding further development efforts. Building upon this foundation, an iterative ideation process was taking place, where multiple ideas were generated using brainstorming, prototyping, and matrices. Three Value Creating Strategies, based on three different scenarios of market outcomes, were created and used for evaluation of the concepts. Concepts, with high expected value in a “one size fits all-with-the-same-needs”-scenario were further developed. The study resulted in the design of a maintenance platform as well as three design concepts of modules, all with different materials, manufacturing methods, installation and life-cycle approach. The final modules’ designs were thereafter evaluated based on cost-efficiency, maintainability, and environmental sustainability criteria. Recommendations for further development followed. The findings underscore a significant demand and potential for a modular, cost-efficient fish passage. Nonetheless, ensuring successful implementation entails further testing and evaluation.