Amsterdam’s Moonwatt secures €7.6M to scale solar-only storage with sodium-ion batteries

Amsterdam-based Moonwatt, a company building solar-only energy storage systems using sodium-ion batteries, has secured $8.3M (approximately €8M) in funding in a Seed round.

The seed round is co-led by Daphni and LEA Partners, with participation from Founders Future, AFI Ventures (by Ventech), and Kima Ventures, alongside strategic business angels and customers.

The funding will help speed up the development and use of Moonwatt’s hardware and software, grow the team, and support the move toward a cleaner and more reliable energy system.

Moonwatt: Develops a battery storage system

Moonwatt was co-founded by Zukui Hu, Guillaume Mancini, and Valentin Rota, who met during their time at Tesla Energy nine years ago and have been working together since.

Moonwatt’s battery energy storage system is designed to address the issues of solar energy, such as reliability, cost, and grid congestion.

Zukui Hu, CEO and Co-Founder of Moonwatt says, “We started our product design from a blank sheet of paper, freeing ourselves from legacy features inherited from other segments of the battery industry, to design a system from scratch that is fundamentally cheaper, safer and more reliable. Our vision is a product that can be deployed anywhere, and that can be scaled up multiple orders of magnitude without facing raw materials scarcity.” 

Instead of using lithium-ion batteries, Moonwatt employs sodium-ion technology, which is 1000x more abundant, a third cheaper and safer alternative.

This makes it a practical choice for energy storage. When used with solar plants, these systems can increase energy efficiency from 15-20 per cent to about 80 per cent.

This improvement can help reduce the need for costly upgrades to the power grid, minimise congestion, and stabilize energy prices.

This approach has the potential to significantly reduce carbon emissions by up to 14 gigatons of CO2 annually by 2050, claims the company.

The system is intended for solar plants producing at least a few hundred kilowatts of energy, excluding small residential solar installations.

The storage system is designed in a distributed way, making it easier for plants to integrate. This setup is expected to improve efficiency and lower the costs of dispatchable electricity by connecting storage units closer to the solar panels during peak output.

According to the startup, its approach can help solar power plants make more money by selling more solar energy, especially when prices are higher. It also aims to cut costs by sharing some electrical infrastructure. 

“Basically, what we allow our partner to do is to double their return,” co-founder and chief commercial officer, Valentin Rota, tells TechCrunch. “So in AAA [credit-rating] country, I would say an average PV [photovoltaic] asset is around, let’s say 8 per cent to 12 per cent return — IRR — and we will bring the asset up to around 20 per cent.”

Moonwatt offers a storage system that can increase a solar plant’s capacity factor up to 80 per cent. Plants that use this system might be able to double their internal rate of return (IRR), reports Tech Crunch.

“We started to see this application first starting on what we call microgrids, so usually a small grid-resistant generator,” says Rota. “But as the cost of batteries went down and the cost of storage went down actually those applications started to arrive in bigger countries on bigger grids, and it’s driven by the fundamental pace of solar.”