Oceanic Energy Storage: Sizable Energy’s Innovative Solution to Grid-Scale Power Challenges

The Limitations of Traditional Energy Storage

As the world transitions toward renewable energy sources, the challenge of storing electricity for when it’s needed most has become increasingly critical. Traditional pumped-storage hydropower has served as one of humanity’s most significant energy storage solutions for over a century, with global capacity reaching approximately 8,500 gigawatt-hours according to the International Energy Agency. These massive systems function by pumping water to higher elevations during periods of low electricity demand and releasing it through turbines to generate power during peak demand. However, their geographical constraints and substantial infrastructure requirements limit their potential for widespread adoption in our rapidly evolving energy landscape.

The Limitations of Traditional Energy Storage
From Italian Reservoirs to Ocean Innovation
Sizable Energy’s Marine Storage Technology
Advantages of Offshore Energy Storage
Commercial Prospects and Development Timeline
Integration with Renewable Energy Infrastructure
The Future of Grid-Scale Energy Storage

From Italian Reservoirs to Ocean Innovation

Manuele Aufiero’s childhood experiences with pumped hydro facilities in northern Italy planted the seeds for what would become a revolutionary approach to energy storage. “I’m in love with pumped hydro,” Aufiero confessed, “but it’s just not enough to keep up with renewables.” This realization sparked his quest to reimagine energy storage by moving the concept to the ocean, leading to the founding of Sizable Energy, a startup dedicated to overcoming the limitations of land-based energy storage systems., as detailed analysis, according to expert analysis

Sizable Energy’s Marine Storage Technology

The company‘s innovative design resembles an underwater hourglass system featuring two flexible, sealed reservoirs connected by a plastic tube housing turbines. The upper reservoir floats near the surface while the lower one rests on the seabed. The system operates on a simple but brilliant principle: during periods of low electricity demand and cheap power, turbines pump supersaturated saltwater from the bottom reservoir to the top. When the grid requires additional electricity, a valve opens, allowing the dense, salt-concentrated water to flow downward through the turbines, generating electricity as it returns to the lower reservoir.

“From the energy balance point of view, what we are doing is lifting blocks of salt,” Aufiero explained. “But instead of using cranes, we dissolve it and pump it just because it’s easier, simpler. Other than that, we are just lifting a heavy amount of salt.” This elegant solution harnesses fundamental physics to create a reliable, scalable energy storage system., according to market insights

Advantages of Offshore Energy Storage

Moving energy storage offshore offers several distinct advantages over traditional land-based systems. Most significantly, it enables mass production of standardized components rather than requiring custom engineering for each geographical location. “Every time you build pumped hydro on shore, you have to design a concrete dam for that specific site, and you have to adapt the technology there,” Aufiero noted. “Building offshore allows us to streamline production, and everything we do is identical, regardless of the final deployment site.”

The standardization potential could dramatically reduce costs and deployment timelines while increasing reliability. Additionally, offshore placement eliminates the need for scarce mountainous terrain required by traditional pumped hydro facilities, opening vast new areas for energy storage development.

Commercial Prospects and Development Timeline

Sizable Energy recently secured $8 million in funding led by Playground Global, with participation from EDEN/IAG, Exa Ventures, Satgana, Unruly Capital, and Verve Ventures. This financial backing will accelerate the company’s development timeline, which includes deploying a pilot of floating components ahead of a full demonstration plant. The startup aims to deploy several commercial projects worldwide by 2026.

At full scale, each turbine is projected to generate approximately 6 to 7 megawatts of electricity, with one turbine installed for every 100 meters of pipe. Deeper deployment sites offer greater storage potential, and commercial installations would feature multiple reservoir systems. Perhaps most impressively, Sizable Energy anticipates delivering energy storage at approximately €20 per kilowatt-hour (about $23), representing roughly one-tenth the cost of current grid-scale battery storage solutions., according to related coverage

Integration with Renewable Energy Infrastructure

The technology presents particularly promising synergy with offshore wind projects, as shared electrical connections to shore could significantly reduce infrastructure costs. However, the system’s versatility allows connection to any grid near waters reaching at least 500 meters (1,640 feet) in depth. This flexibility positions Sizable’s technology as a potential cornerstone in the global transition to renewable energy.

“We believe that long duration energy storage is required not only for renewable integration, but also for just making the grid resilient,” Aufiero emphasized. “There is no way we can keep up with that with traditional pumped hydro or batteries. We need something new.”

The Future of Grid-Scale Energy Storage

As global energy storage needs continue to grow alongside renewable energy deployment, innovative solutions like Sizable Energy’s oceanic storage system will play an increasingly vital role in maintaining grid stability. The company’s approach addresses multiple challenges simultaneously: providing long-duration storage, reducing costs through standardization, and utilizing abundant offshore spaces rather than limited terrestrial sites.

While the technology is still in development, its potential to transform how we store and manage electricity could prove instrumental in achieving a fully renewable energy grid. As Aufiero’s childhood fascination with Italian reservoirs evolves into a sophisticated marine energy storage solution, Sizable Energy represents the kind of innovative thinking necessary to overcome the world’s most pressing energy challenges.