The capital, raised in a round led by venture capital firms NordicNinja and Voima Ventures, could support the company’s industrialisation plan and a manufacturing facility for its battery technology, which could scale seasonal energy storage.

Photoncycle’s system uses solar energy generation to provide electricity to households. Excess energy can be used to electrolyse water and produce hydrogen, which is stored underground in a solid state. During periods of low solar generation, the hydrogen can be converted back to electricity through a fuel cell.

The company has revealed few technical details about the system, but argues it could replace water-based heating systems, enabling households or businesses to store summer solar power for winter heating use.

The company operates on a subscription basis with a monthly fixed fee paid on top of an initial refundable deposit.

Funds raised by the round will be used for the company’s commercial rollout, first targeting Denmark and following on to focus on further European markets. It will also fund a 1.4TWh manufacturing facility, which, according to Photoncycle, could produce systems storing energy for 140,000 homes annually.

While hydrogen microgrid systems have played a role in offgrid uses like telecoms, hydrogen’s role in domestic settings for applications like boiler fuel replacement has been widely criticised due to its high costs and concerns around safety.

However, Bjørn Brandtzæg, Chief Executive of Photoncycle, said the system had the potential to advance seasonal energy resilience for households in Europe.