Moonwatt Secures $8.3M for Sodium-Ion Solar Storage

The Growing Importance of Battery Technologies in the Energy Transition

The push to reduce carbon emissions through electrification and the adoption of clean energy sources is significantly boosting interest in battery technologies. Effective energy storage is crucial for facilitating a successful transition to a greener economy.

Renewable energy sources, while cleaner than fossil fuels, often exhibit inconsistent power generation. Solar energy, despite its rapid growth in recent years, ceases production when sunlight is unavailable.

Addressing Solar Energy Variability with Storage Solutions

A key strategy for managing the fluctuating output of solar plants involves storing excess energy generated during peak production times, such as daylight hours. This stored energy can then be deployed when needed, including periods of high demand, which frequently occur when sunlight is limited.

Introducing Moonwatt: A Novel Energy Storage System

Founded in September of last year in the Netherlands, Moonwatt is a clean tech startup focused on developing a battery-based energy storage system. This system is specifically designed to be co-located with solar power plants and optimized for managing their inherent variability.

The company’s development includes purpose-built battery enclosures, inverter power electronics for grid connectivity, and the necessary software for seamless integration and system management.

Benefits of Moonwatt’s Approach

Moonwatt asserts that its system will empower solar plants to enhance revenue streams by enabling the sale of more solar energy, particularly during periods of higher energy prices. Furthermore, it aims to reduce operational costs by sharing electrical infrastructure components.

The target market for Moonwatt’s technology includes solar plants generating at least several hundred kilowatts of power, excluding smaller residential photovoltaic installations.

Sodium-Ion Batteries: A Cost-Effective Alternative

Sodium-ion cells are at the core of Moonwatt’s energy storage system. This technology presents a compelling alternative to lithium-ion batteries due to its reliance on more affordable and readily available raw materials, contributing to lower overall costs.

Considerations and Advantages of Sodium-Ion Technology

While sodium-ion batteries can be larger and heavier than lithium-ion cells due to lower energy density, this is less of a concern for stationary applications.

This makes the technology particularly well-suited for renewable energy storage installations where space is not a limiting factor, and weight is less critical than cost-effectiveness.

The technology is gaining momentum as a lower-cost storage option for renewables.

Maximizing Energy Output from Photovoltaic Systems

Moonwatt proposes a solution for solar power facilities: an energy storage system designed to elevate their capacity factor, potentially reaching up to 80%. The company asserts that adopting their technology could lead to a doubling of the internal rate of return (IRR) for participating plants.

According to co-founder and chief commercial officer, Valentin Rota, Moonwatt empowers its partners to significantly improve their financial outcomes. He explained to TechCrunch that a typical PV asset in a country with a strong credit rating—ranging from 8% to 12% IRR—could see its return boosted to approximately 20% with their system.

The Team Behind Moonwatt

The company was founded by a team of three: CEO Zukui Hu, CTO Guillaume Mancini, and Valentin Rota. Their collaboration began nearly ten years ago while developing battery technology for Tesla. They have maintained a working relationship through various roles and projects, including experience with smaller, independent solar storage installations.

Rota notes that their initial observations centered on the application of this technology in microgrids—small, resilient power generators. As battery costs decreased, these applications expanded to larger grids, driven by the increasing prevalence of solar energy.

Prior to Moonwatt, the founders also collaborated at Freyr (now Ti Energy), a battery manufacturer. Rota states that the realization that they could leverage their combined expertise in battery hardware and technology to enhance solar storage performance sparked the creation of Moonwatt—a name intentionally chosen as an energetic take on the term “moonshot.”

“We identified a gap in the market,” Rota explains. “While solar storage is crucial for the future power grid, there wasn’t a product specifically engineered for it. Moonwatt aims to fill that void by delivering a dedicated battery storage solution for solar energy.”

Addressing a Growing Market Need

With the global production of solar energy rapidly increasing, Moonwatt anticipates a growing demand for specialized storage solutions, moving away from generalized, “cookie-cutter” products.

Sodium-ion battery technology is a key differentiator for Moonwatt, offering advantages in scalability, cost reduction, and a smaller carbon footprint compared to lithium-ion alternatives, as highlighted by Rota.

Furthermore, their storage system employs a distributed architecture, simplifying integration for existing plants. This approach also enhances efficiency and lowers the cost of dispatchable electricity by connecting storage directly to solar panels at their peak output.

“Ultimately,” Rota concludes, “our objective is to reduce the overall cost of electricity generated by these dispatchable solar plants through these combined features.”

Accelerating Development with Seed Funding

Although still in its nascent stages, with a prototype recently developed, Moonwatt has successfully secured €8 million in seed funding – equivalent to approximately $8.3 million based on current exchange rates. This investment will be utilized to expedite the development and market launch of their energy storage technology.

A pilot installation is currently being planned for a location within Europe, anticipated to commence next year. Following this, the company projects its initial commercial deployments to begin in 2027.

The seed funding round was jointly led by Daphni and LEA Partners, with further participation from Founders Future, AFI Ventures (affiliated with Ventech), and Kima Ventures. Strategic business angels and existing customers also contributed to the round.

Paul Bazin, a partner at Daphni, expressed his support, stating that Moonwatt’s approach represents “the crucial advancement the industry has been awaiting.”

He elaborated, “The expansion of renewable power has surpassed expectations, but we are nearing a point where further scaling will be hindered without improved energy storage solutions. Moonwatt, founded by seasoned industry professionals, is addressing this challenge with a unique storage product specifically designed for solar energy applications.”

Rota emphasizes the company’s ambition, stating, “We harbor a strong desire to become a gigawatt-hour scale player, a significant force in the market, as we are committed to making a substantial impact.” He further notes that achieving scale is intrinsically linked to cost management, a critical factor in this industry.

The decision to concentrate on solar energy, according to Rota, is driven by its favorable economic profile and widespread adoption.

“Solar energy is particularly appealing due to its competitive cost per megawatt-hour, a cost that continues to decrease,” he explains. “Furthermore, solar energy is already being implemented in over 120 countries annually, demonstrating its global reach.”

By focusing specifically on solar, the startup can dedicate its resources to optimizing design choices that maximize the performance of solar plants, including minimizing the expenses associated with grid connection.

“Looking forward, reducing the costs of solar energy requires a reduction in overall balance of plant costs. This involves minimizing the need for transformers, cabling, and related infrastructure. This can be achieved by integrating solar and storage at the low voltage level – positioning them in close proximity to each other,” Rota suggests.

“This shared electrical infrastructure streamlines the connection to the grid. On a broader, national level, optimizing grid capacity utilization is also essential. Currently, a standalone solar plant utilizes its grid capacity only around 20% of the time. However, integrating storage allows for energy usage to be shifted, resulting in a more efficient use of grid resources.”

The company’s objective extends to assisting solar plants in transitioning from developers reliant on feed-in tariffs to – as Rota describes – “nearly” becoming energy traders with a more adaptable asset.