Norwegian energy storage scale-up Photoncycle has secured €15 million in Series A funding to commercialise its solid-state hydrogen–based seasonal storage system.
The round was led by NordicNinja and Voima Ventures, alongside existing backers Lifeline Ventures, Eviny Ventures, Luminar Ventures and Momentum. As revealed to TFN, “Photoncycle has raised €15 million to date,” but the valuation has not been disclosed.
Tackling Europe’s seasonal energy vulnerability
Europe’s energy crisis reinforced a long-standing weakness: abundant summer renewables are not matched by winter demand. The core issue is the structural mismatch between renewable energy production and household energy consumption, particularly in Northern Europe. The company revealed to TFN that there are three key data points that illustrate the problem:
- Seasonal mismatch: Solar production peaks in summer, while household energy demand, especially heating, peaks in winter. In countries like Denmark, solar generation in summer can be up to 15 times higher than in winter.
- Grid dependence and rising tariffs: Even homes with solar panels remain heavily dependent on the grid during the winter months. Due to electrification and grid upgrades, tariffs in some markets are expected to increase by up to 50% over time.
- Electrification pressure: As heating transitions from fossil fuels to electric solutions such as heat pumps, peak demand increases, further stressing grid infrastructure and driving system costs.
Photoncycle’s technology directly targets this seasonal mismatch. By converting surplus summer solar energy into solid-state hydrogen stored underground, households can draw clean heat and electricity during colder months. At full industrial scale, the proposed 1.4 TWh facility would provide enough storage capacity for 140,000 homes, each storing roughly 10,000 kWh of seasonal energy.
This distributed approach reduces the volume of imported gas required to meet winter demand, strengthening regional energy independence and easing exposure to volatile global gas prices.
How an MIT idea became the blueprint for Photoncycle
The company stated, “Photoncycle was founded in Norway by Bjørn Brandtzaeg, a seasoned energy entrepreneur who has worked in large-scale renewable energy infrastructure throughout his career. He has led the development of major energy projects internationally, most recently two large-scale renewable projects in the Caucasus region. Across his career, he has raised more than $1.3 billion for energy infrastructure projects.”
He continued stating, “Through this work, he experienced firsthand both the complexity and vulnerability of centralised energy systems. He became convinced that a more distributed model for energy production and storage would be essential for the future. At the same time, he saw how difficult it was for homeowners to secure reliable and affordable renewable energy solutions. After exiting his previous company, Brandtzaeg attended MIT in 2020, where he collaborated with experts working on next-generation energy systems. There, he developed the concept behind Photoncycle, a residential system that allows households to store excess renewable energy produced in summer and use it in winter, effectively solving the seasonal storage challenge. Building on his experience, he assembled a multidisciplinary and international team of engineers and chemists to bring the system to market.”
What are the diversity statistics?
As an early-stage deep-tech company, the team is still relatively small. We are committed to building a diverse and inclusive organisation as it scales, and diversity is an active consideration in all hiring processes.
A subscription model built for affordability
One barrier to mass adoption of home energy storage is the upfront cost. Photoncycle aims to remove this friction with a subscription-based offering that includes solar panels, storage hardware, servicing and access to energy trading markets.
The model targets predictable year-round energy bills and reduced reliance on gas, especially in countries where prices are high, and regulations encourage alternatives. Denmark is a clear proving ground: 300,000 Danish homes still depend on gas systems scheduled for phase-out by 2035, and Photoncycle already reports a fast-growing waiting list of households seeking cleaner, long-term solutions.
This early enthusiasm signals a strong appetite for household-level seasonal storage, a category that has largely been missing from Europe’s renewable transition toolkit.
Plans for the next 12 months
Over the next 12 months, Photoncycle will focus on the final product development and system testing, certification and regulatory approvals, establishing a manufacturing line, expanding pre-orders, and preparing for first customer shipments in Q3 2027.
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,” he 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.”
Tomosaku Sohara, General Partner at NordicNinja, said: “From our perspective of bridging Japanese capital and European startup expertise, we strongly believe energy sovereignty must be strengthened across both Europe and Asia. Photoncycle combines deep technical innovation with a clear, scalable path to global deployment. Long-duration energy storage is critical to building resilient, reliable clean energy systems in Europe, Japan and beyond. We’re excited to help introduce the team to global opportunities, building on our long experience in the energy sector.”
Inka Mero, Founder and Managing Partner at Voima Ventures, said: “As the share of renewable energy increases, structural price volatility in electricity markets is rising. Seasonal storage is therefore not a niche solution, but a systemic necessity. Photoncycle addresses this imbalance by enabling households to store energy across seasons and reduce their dependence on imported fossil fuels. This is an important building block for a resilient and sovereign European energy system.”
