Photoncycle raises €15M to scale seasonal energy storage in Europe

Norwegian energy storage scale-up Photoncycle has raised €15 million in Series A funding to address a key renewable energy challenge in Europe: enabling households to store surplus summer solar power for winter heating and electricity. The round was led by NordicNinja and Voima Ventures, with participation from existing investors Lifeline Ventures, Eviny Ventures, Luminar Ventures and Momentum.

Photoncycle develops solid-state hydrogen energy storage systems that allow households and businesses to store excess renewable energy for seasonal use. Its patented technology converts surplus solar power into solid-state hydrogen stored underground and releases it later as clean heat and electricity when needed.

The investment comes as Europe continues to face energy vulnerabilities exposed by the 2022 crisis. In 2025, the EU imported €396 billion in fossil fuels (about €880 per citizen), underscoring ongoing reliance on external supply. Winter risk remains high, with space heating accounting for 62.5 per cent of household energy use and natural gas still a major component.

Photoncycle’s distributed, household-level seasonal storage is designed to reduce the volume of imported gas required to meet winter heating demand. At full industrial scale, the company’s proposed 1.4 TWh manufacturing facility would represent storage capacity equivalent to roughly 140,000 homes each storing 10,000 kWh of seasonal energy.

Bjørn Brandtzæg, founder and chief executive of Photoncycle, said the company was focused on moving seasonal energy resilience closer to consumers:

Europe is beginning to solve short-duration storage. 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.

The company plans to offer its system through a subscription-based model covering solar panels, storage, servicing and access to energy trading markets, with the aim of lowering upfront costs for homeowners. By shifting summer solar energy into winter use, Photoncycle aims to provide households with more predictable year-round energy costs and reduced exposure to volatile gas markets.

The new funding will support commercial rollout in Denmark and the Netherlands and finance the first phase of the company’s industrialisation plan, including the proposed 1.4 TWh annual manufacturing facility. Beyond its initial European markets, Photoncycle also sees longer-term expansion opportunities in regions such as Japan and the United States.