Hydropower potential on the river Sihl and its tributaries, study on feasibility and economic viability
Location
Commune of Adliswil / Switzerland
project period
11/2023 to 11/2024
client
CSD Ingenieure, on behalf of the Town of Adliswil
Services provided
Consultancy
Partner organisation
In spring 2023, the Adliswil municipal council (town parliament) submitted a motion asking the town council to clarify the potential for hydropower in Adliswil (to accelerate the achievement of climate targets of the municipality). The analysis did comprise small tributaries in the municipal area as well as options on the Sihl river, especially at the two existing transverse structures. The longitudinal conductivity and thus the ecological condition of the watercourse could be significantly improved by a hydropower plant and the associated obligation to build a fish passage.
Objective: Assessment of the overall available hydropower potential in the municipal area of Adliswil to increase the percentage of electricity from renewables with regards to climate targets.
Services provided by Skat:
- Hydrological assessment of the hydropower potential of the river Sihl and its tributaries: catchment area analysis, flow duration curve, determination of design flow, flood flow and residual flow for the most promising potential hydropower site “Sihlau”
- Implementation of a (rough) feasibility analysis: analysis of different technical variants, technical design of all system components, environmental analysis, cost-benefit and economic analysis, possible support/ subsidy measures and electricity marketing, electricity production cost and current tariffs, energy balance and emission analysis
Results: The analysis of the use of hydropower at the existing weir describes an optimal solution for generating clean electricity from the Sihl near Adliswil. The concept is based on state-of-the-art technology and the latest findings for the ecological rehabilitation of existing hydropower plants. The construction of the small hydropower plant would also allow synergies to be exploited between the ecological restoration of the weir and the use of hydropower. The overall project would make the weir passable for fish and would also not impair the discharge during floods. The electricity production of the small hydropower plant is roughly equivalent to that of a new PV system covering an area half the size of a football pitch and covers the needs of around 150 households. The proportion of winter electricity is around half of the annual production.