Local energy solutions help tackle global challenges
Sergi Aguacil with a view of the future Smart Living Lab's building. © T.Delley/behnischarchitekten
In this article originally appearing in French, Sergi Aguacil, an architect and head of the Building2050 Group at EPFL’s School of Architecture, Civil and Environmental Engineering (ENAC), discusses the research he’s doing at the Smart Living Lab in Fribourg to develop distributed power generation and seasonal storage systems for buildings.
Recent geopolitical developments have shown just how vulnerable many countries are when it comes to their energy supply. In addition to energy-saving measures, another way of tackling this problem is through the use of distributed power systems for buildings. This kind of local power generation can be particularly effective given how much of buildings’ surfaces are exposed to sunlight. Building owners in Switzerland are waking up to the potential of solar power – the number of installed facilities grew by 43% between 2020 and 2021. But in most cases, solar panels are installed only on building rooftops, even though some facades receive enough sunlight to generate just as much solar power.
The solar energy captured on a facade can be turned into electricity with photovoltaic (PV) cells or into hot water with solar thermal collectors. One of the keys to getting the best performance out of these kinds of systems is picking the right building surface to “activate.” By tailoring the approach to the individual circumstances of each building, energy can be produced exactly when and where it’s needed.
Other types of technology are available for seasonal storage.
Seasonal storage essential for zero-energy buildings
Because the amount of sunlight can vary, building operators need to be able to store the energy that’s produced. Power from PV cells can be stored in batteries for short periods of time, while other types of technology are available for seasonal storage, such as systems that convert solar power into hydrogen. These systems are designed to make buildings as self-sufficient as possible and minimize their dependence on power grids.
In a recent study, experts at Building2050 Group and the Fribourg School of Engineering and Architecture (HEIA-FR) sized a hydrogen-based storage system for the Smart Living Lab building that’ll soon be built on EPFL’s Fribourg campus in the Bluefactory innovation park. Construction is slated to begin later this year. The system will be connected to PV cells that are integrated into the building envelope using various technologies and other innovations. For this project, Building2050 Group worked with specialized experts and construction-industry firms.
In addition to a conventional lithium battery, the building will also have a hydrogen-based seasonal storage system. Together, these devices will enable the building to run 50% on its own energy and help reduce peak load on the grid.
Like a battery
From the perspective of building operators, the hydrogen-based system works essentially like a battery. The excess solar power generated by the PV cells is used to produce hydrogen, which is stored in the summer and converted back into power in the winter by a fuel cell. The heat created by this process can be recovered in the form of hot water that’s either pumped into the building’s heating system or used for hot water within the building. In addition to bringing buildings one step closer to zero-energy, power storage systems make optimal use of solar power through the seasons, in a sustainable way.
Sergi Aguacil, the head of Building2050 Group, Smart Living Lab, EPFL, Fribourg
- This article was published in three local dailies – La Côte (Vaud Canton), Le Nouvelliste (Valais Canton) and Arcinfo (Neuchâtel Canton) – in September 2022 under a joint initiative between EPFL and ESH Médias to showcase the R&D being carried out at EPFL on advanced construction techniques.