Project Report

Sun on the roof of the Lilienberg

120 kilowatt-peak solar power plant – a project with substance

Those who think entrepreneurially don't just look ahead – they also look upwards. At the rooftops. At the space that remained unused for years and is now quietly doing what good investments do: creating long-term added value. Lilienberg in Ermatingen on Lake Constance has taken this step – and done it in a way that suits the foundation: with care, with conviction, and with a focus on what's essential.

A 120 kWp photovoltaic system is currently being installed on the roofs of the hotel's main building. Bifacial modules from the German manufacturer Voltara are being used – a technology that generates electricity from both sides: from above through direct sunlight and daylight, and from below thanks to reflection from the roof surface. The result is a system that performs better than its specifications indicate – reliably, year after year. The project is being realized by Alpensolar, a young Swiss company, for whom this is its largest project to date.

Quality you can't see – but you can feel.

What distinguishes this project is not its spectacular nature, but its consistency. The modules are designed to remain invisible to guests. Those strolling through the park, those looking up from the lake, will see nothing. The northwest and southeast orientation was deliberately chosen so that the system blends seamlessly into the building's appearance. The main roof faces east: those arriving via the park view the building from the west – and therefore don't notice the solar panels at all. In the mornings, the rising sun illuminates the surface directly for almost half the day. An elegant solution that reconciles aesthetics and efficiency.

And yet: The system will cover between 20 and 25 percent of Lilienberg's total electricity needs – with a conservatively calculated amortization period of seven to eight years. Those familiar with the experience of comparable Voltara installations tend to expect less. In practice, the modules regularly deliver more than the manufacturer's specifications promise.

"It's simply unique. The more difficult the task, the further you progress as a company. That was the idea behind why I absolutely wanted this project."

Managing Director, Alpensolar

What makes the Voltara modules technically special is their everyday reliability. They produce energy not only in direct sunlight but also in diffuse daylight – a crucial advantage in a location like Lake Constance with its fluctuating light conditions. And where other systems cause an entire row of modules to fail due to partial shading, the remaining arrays simply continue operating – thanks to integrated shading optimization. The modules' uniform black appearance also ensures that the system has a visually cohesive look.

The installation went more smoothly than expected. Only a last-minute adjustment to the substructure – a deliberate decision to ensure long-term compatibility with the roof – caused a delay of a few days. For a system of this size, typically completed in about two weeks, this is a negligible detail. And for Alpensolar's employees, the main building's roof also offers a practical advantage: its shallow pitch makes working on it safer than on steeper buildings.

 

Two companies, one shared logic

What's particularly moving about this project is the attitude behind it. The project manager from Alpensolar describes how he first visited Lilienberg and knew immediately: this is the project he wants. Not because of the size of the roof – but because of the grandeur of the place. He recounts months spent mentally planning the project before the contract was officially signed. Module by module, detail by detail. He speaks of the shift in mindset this place triggered in him. And of his firm conviction that this isn't just a one-off project, but the beginning of a long-term collaboration.

The name Lilienberg Entrepreneur Forum Foundation stands for entrepreneurial thinking and future-oriented action – and it is no coincidence that Lilienberg also follows this logic when choosing its partners. They are not looking for mere service providers, but companies that think similarly: long-term, meticulous, with genuine high standards for their own work. Alpensolar has demonstrated this – and Lilienberg has recognized it.

Those who work with Lilienberg grow from it. This applies to guests and seminar participants – and apparently also to companies that leave their mark here. The solar panels on the roof of the main building are silent witness to this: barely visible, but effective. For the next 20 to 30 years.

The sun rises every morning over Lake Constance – from now on it will also work for the Lilienberg.