Photoncycle Raises $16.2M for Seasonal Solar Storage

Jan de Vries · 2026-03-04

Here's a story that feels like a glimpse into a smarter energy future. Photoncycle, an Oslo-based energy storage startup, just secured $16.2 million in Series A funding. Their mission? To help households store excess solar power from the summer and use it to heat their homes in the winter. It's a simple idea with profound implications. The funding round was led by NordicNinja and Voima Ventures, with support from existing backers like Lifeline Ventures and Eviny Ventures. ### The Big Problem: Seasonal Energy Gaps Think about it. We've gotten pretty good at storing energy for a few hours, maybe a day. But what about storing sunshine from July to keep you warm in January? That's the massive, unsolved puzzle Photoncycle is tackling. As founder and CEO Bjørn Brandtzæg puts it, "Europe is beginning to solve short-duration storage. The remaining gap is seasonal." He explains that if families can bank summer energy, they slash their exposure to volatile imported fuel prices and rising grid costs. It's about taking back control. ### How Their Solid-State Hydrogen Tech Works Founded in 2020, Photoncycle is building what it calls the distributed storage backbone for Europe's renewable future. Their patented system is fascinating: - It converts surplus solar or wind power into solid-state hydrogen. - That hydrogen is stored safely underground on the property. - When heat or electricity is needed months later, the system releases it as clean power. It's like having a personal energy savings account for your home, with summer deposits and winter withdrawals. ### Why This Matters Now More Than Ever The 2022 energy crisis was a brutal wake-up call, exposing how vulnerable the system is. Photoncycle points out that the EU imported a staggering $428 billion worth of fossil fuels in 2025. That's roughly $950 for every single citizen. The winter problem is especially acute. Space heating eats up 62.5% of a home's energy use. With natural gas still dominating, families are hostages to global price swings every cold season. ### The Road Ahead: Scaling a Solution So, what's next with this fresh capital? The company is focusing its commercial rollout in Denmark and the Netherlands first. A big part of the plan is financing a massive new manufacturing facility. At full scale, this facility could produce enough seasonal storage capacity for about 140,000 homes. To make it accessible, Photoncycle plans a subscription model. That would cover the solar panels, the storage system, servicing, and even access to sell power back to the grid. Interest is already surging. In Denmark, where energy costs are sky-high and 300,000 homes still use gas heat (set to be phased out by 2035), waiting lists for the system are growing fast. Inka Mero of Voima Ventures captured the bigger picture perfectly: "Seasonal storage is therefore not a niche solution, but a systemic necessity... This is an important building block for a resilient and sovereign European energy system." The initial focus is Europe, but the vision is global. After proving the model in Denmark and the Netherlands, the technology could scale to other major markets, including opportunities in Asia and the United States. It's a compelling step toward energy independence, one household at a time.