What happens when solar power meets fluctuating electricity prices?
Dynamic electricity tariffs change the economic efficiency of photovoltaic systems. In their bachelor's thesis, two ZHAW students show how solar power, consumption and fluctuating market prices interact – and why south-facing systems can have economic advantages. This is one of many practical projects at the Institute of Energy Systems and Fluid Engineering (IEFE) at the ZHAW School of Engineering.
How do dynamic electricity tariffs affect the planning and economic efficiency of photovoltaic systems? Gian-Luca Bühlmann and Max Eidtmann investigated this question as part of their bachelor's thesis at the ZHAW School of Engineering. Their conclusion: time-dependent tariffs fundamentally change the game.
For their analyses, the two students modified their own calculation model for determining the economic efficiency of PV systems. They used it to investigate how solar power, electricity consumption and time-dynamic feed-in tariffs interact in PV systems on flat roofs – with surprising results. Their simulation shows that the mostly east-west-facing, flat-mounted systems are particularly economical in the summer, when market prices are at their lowest. South-facing systems, on the other hand, score points in winter with better-paid electricity and will benefit particularly from the planned minimum remuneration from 2026 onwards. The bottom line is that they are economically attractive.
In their work, the two aspiring engineers combine the planning and simulation of photovoltaic systems, economics and software development – an interdisciplinary approach that is typical of many bachelor's theses at the Institute of Energy Systems and Fluid Engineering (IEFE). At the institute, knowledge of electrical, chemical and thermal energy systems is not only taught theoretically, but also applied in a practical manner.
The variety of topics covered at IEFE is impressive: from refrigeration machines, heat pumps and micromotors for satellites to photobioreactors, power grids and bidirectional charging of electric vehicles – innovative solutions with real practical relevance are emerging everywhere.
A selection of this year's bachelor's theses from the various technical degree programmes can be found in the following publication:
https://www.zhaw.ch/storage/engineering/studium/ZHAW-Engineers-2025.pdf
Project name
Impact of time-dependent grid tariffs on the economic efficiency of photovoltaic systems
Participants
Students: Gian-Luca Bühlmann und Max Eidtmann – Studiengang Energie- und Umwelttechnik
Support: Hartmut Nussbaumer, Institut für Energiesysteme und Fluid-Engineering (IEFE)
Pascal Vögeli, Institut für Nachhaltige Entwicklung (INE)
Project duration
January 2025 till June 2025