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Behind the Inverter Storage Pilot Project
As Switzerland accelerates its energy transition, photovoltaic installations are multiplying across rooftops and industrial sites. Yet the real bottleneck lies not in producing solar energy — but in storing and using it efficiently. Most photovoltaic systems today feed energy directly into the grid or use complex hybrid inverters to store it in batteries. This model is costly, technically rigid, and environmentally inefficient. The need to install a second inverter for battery connection increases material use, installation time, and carbon footprint — while locking consumers into proprietary systems that limit interoperability and restrict innovation.
Meanwhile, thousands of batteries from electric micromobility reach the end of their first life each year in Switzerland. These batteries still hold up to 80 % of their capacity — an untapped resource for second-life storage solutions that could stabilize local grids and make communities more energy independent. The current system, however, prevents these batteries from being reused efficiently. The challenge is both technical and systemic: how can we make local, second-life energy storage simple, affordable, and compatible with existing photovoltaic installations?
equivalent due to second-life batteries and avoided inverter production
The “Behind the Inverter” pilot project, led by Evolium Technologies with partners OIKEN, Studer Innotec, Digital Logic, and the HES-SO Valais–Wallis, proposes a breakthrough: a compact DC/DC converter that allows a second-life battery to connect directly to the DC bus of any existing solar inverter — without modification. This elegant approach eliminates the need for a second inverter, reducing installation costs and environmental impact by up to 80 %, while enabling energy storage and reuse at a fraction of today’s cost.
The converter, fully designed and assembled in Valais, will be integrated into Evolium’s modular second-life battery systems. It operates autonomously, dynamically adjusting charge and discharge to optimize energy flow between solar panels, batteries, and household demand. The system communicates via smart meters and home energy management systems, creating a flexible, intelligent energy loop suitable for residential and community-scale applications.
By avoiding double conversion losses, the solution can increase the overall energy efficiency by 10–15 %, cut installation costs by 75 %, and extend the useful life of lithium-ion batteries by giving them a second life of up to 10 years.
“The current generation of photovoltaic systems is efficient in production, but still wasteful in integration. We must learn to reuse, reconnect, and rethink.”
This project represents a new paradigm for decentralized energy storage — one that is open, circular, and locally rooted. By merging second-life batteries with smart, interoperable technology, the “Behind the Inverter” solution enables Swiss households to consume their own solar power more efficiently, reducing dependency on the grid while contributing to national energy resilience.
The pilot will culminate in a certified, market-ready product (TRL 8–9), tested under real conditions with OIKEN’s network. Beyond its technical innovation, it strengthens regional industrial capacity, creating 8 full-time local jobs and positioning Valais as a pioneer in circular energy technologies.
In doing so, it answers one of the key challenges of the Swiss Energy Strategy 2050: building a renewable energy system that is flexible, participatory, and sustainable.
