Bachelor’s Thesis 2026 – Guillaume Beaud
The project FuturoSTEP plans to centralise the treatment of wastewater from ten municipalities in the Chablais region within a shared regional infrastructure. The creation of this new network requires the transport of large volumes of wastewater across an area characterised by significant differences in altitude. These altitude differences represent a potential energy resource that could be harnessed by small hydroelectric power stations.
The aim of Guillaume Beaud’s Bachelor’s thesis was to identify this potential, select the most promising sites and assess their technical and economic feasibility. The study thus covers the entire process, from analysing flow rates to the preliminary sizing of hydroelectric equipment, right through to assessing their profitability.
Identify opportunities for upselling
Following a review of the current state of the art in wastewater turbine generation and an examination of several existing facilities in Switzerland and abroad, various options for integrating hydroelectric power stations into the future FuturoSTEP network have been identified.
An initial selection enabled the detailed analysis to focus on three sites located in Champéry, Gryon and on the Troistorrents–Monthey section. For each of them, a typical hydrological year was reconstructed at hourly intervals, distinguishing in particular between inflows during dry weather and during rainy weather.
This detailed approach also highlighted the importance of accurately modelling flow rates over time: simplified estimates based on peak flow rates led to annual production being overestimated by between 49 and 71 %, depending on the site.
From hydropower potential to the preliminary design of power stations
The three selected variants were then subjected to a comprehensive preliminary design process, taking into account the pipework, pressure drops, the selection and sizing of the turbines and generators, and performance under partial load conditions.
One particularly interesting aspect of the project is that several pipes required for the transport of wastewater need to be built regardless of hydroelectric generation. Turbine generation can therefore be integrated into the infrastructure already required for the FuturoSTEP project, thereby significantly reducing the investment specifically required for energy production.
The average annual yields obtained following detailed sizing amount to approximately 478 MWh/year for the Monthey site, compared with 62 MWh per year in Gryon and 24 MWh per year in Champéry.
Synergy with existing projects: the key to profitability
The economic study shows that profitability depends heavily on how the costs of the new infrastructure are allocated, particularly the cost of the pipelines. This item accounts for between 48 and 63 % of the total investment. Where a pipeline is required for the sewerage network in any case, the cost of this does not necessarily have to be borne entirely by the hydroelectric project.
The website of Troistorrents–Monthey clearly stands out as the most attractive option. With an output of around 480 MWh per year, the option under consideration offers a return on investment of approximately 2 to 3 years when the project is managed by the FuturoSTEP project, and between 8 and 11 years when it is used entirely for the hydroelectric project.
The Gryon option offers a lower margin of profitability, whilst the Champéry option is not profitable under the scenarios examined.
Local production to support sanitation infrastructure
The study also highlights the value of self-consumption. The electricity generated can directly power the FuturoSTEP network’s infrastructure, in particular the pumping stations. It is then valued at the price of avoided electricity rather than at the feed-in tariff, which significantly improves the project’s economic viability.
This approach forms part of a broader strategy aimed at multifunctionality and the circular economy : a flow of wastewater that has to be transported and treated in any case also becomes a resource for generating local renewable electricity and reducing some of the energy consumption of the sewerage system.
A project recognised at the Pitch Challenge
The quality of Guillaume Beaud’s work and his ability to communicate the results have also been recognised: He won the 2026 Bachelor’s Thesis Pitch Challenge in Visp.
This study thus illustrates the benefits of incorporating energy recovery from the design or refurbishment of an infrastructure. By capitalising on the work already required for the FuturoSTEP project, certain hydroelectric opportunities are becoming economically very attractive and enable the local generation of renewable electricity from a resource that is currently untapped.
