Norwegian energy resilience startup Photoncycle has raised a €15m Series A led by NordicNinja and Voima Ventures. Existing investors Lifeline Ventures, Eviny Ventures, Luminar Ventures and Momentum also participated in the round.
Photoncycle has developed a breakthrough technology that uses solid hydrogen to store surplus solar energy from household rooftop panels in a cylindrical container buried next to the house, for use in winter. Until now, that level of long-term residential energy storage has not been possible.
This not only limits energy cost spikes during colder months but also makes households self-sufficient and less sensitive to volatile gas markets.
Photoncycle’s solid hydrogen is suitable for long-term storage, but it is also cheap to manufacture and doesn’t require precious metals, unlike batteries, according to Bjørn Brandtzæg, founder and CEO of Photoncycle.
The funding will be used to scale manufacturing and for early commercial deployment, starting in Denmark and then expanding to other large European markets, including the Netherlands. With the assistance of Japanese-European VC Nordic Ninja, Photoncycle is also exploring opportunities in Asia, particularly Japan, and in the US.
Making Europe’s house owners self-sufficient
Brandtzæg, the investment comes as Europe continues to grapple with the structural vulnerabilities exposed by the 2022 energy crisis. The EU's continued dependence on external supply is underscored by the fact that it imported €396bn of fossil fuels in 2025 — around €880 per citizen — even as renewable energy generation expands.
“Europe is beginning to solve short-duration storage,” Brandtzæg said. “The remaining gap is seasonal. If households can store summer energy for winter use, they reduce exposure to imported fuel and price volatility as well as to increasing grid costs for consumers.”
In winter, heating accounts for over 60% of household energy use, while natural gas remains a significant component of residential consumption, leaving households sensitive to seasonal price swings in global gas markets.
In Denmark, where Photoncycle has a rapidly growing waiting list, energy prices are among the highest in Europe; 300k homes still rely on gas-based heating systems, which are set to be phased out by 2035.
The first phase of commercial roll-out is planned to go live in 2027, with 1.4 TWh of annual energy storage capacity — the equivalent of around 140k homes each storing 10k kWh of seasonal energy.
