Sesame Summit 2026 – application open

Sizable Energy raises €7.4M for ocean energy storage

Italian climate tech startup is taking energy storage to the deep. Sizable Energy has raised €7.4M ($8M) to commercialize its ocean energy storage system that stores gigawatt-scale power using gravity and seawater. Playground Global led the round, with participation from Exa Ventures, Verve Ventures, Satgana, EDEN/IAG, and Unruly Capital.

The Milan and Palo Alto-based company is reimagining pumped hydropower for the ocean. Traditional pumped hydro requires specific geography and massive concrete dams. Sizable’s offshore approach sidesteps those constraints entirely.

How Offshore Pumped Hydro Tackles Europe’s Storage Gap

The technology works like an underwater hourglass. Sizable’s system pumps saturated sea-salt brine—20% denser than seawater—between reservoirs on the seabed and floating at the surface. When the grid needs power, gravity pulls the heavy brine down through turbines, generating electricity. When power is cheap, the process reverses.

“Without cost-effective long-duration storage, the grid cannot keep up, regardless of energy source,” said Dr. Manuele Aufiero, CEO and co-founder of Sizable Energy. “Our ocean-based system stores gigawatt-scale power affordably, making the grid more stable, resilient, and ready for the future.”

The company recently completed wave-basin testing at the Maritime Research Institute Netherlands, confirming the system can withstand harsh marine conditions. Sea trials are now underway off Reggio Calabria, Italy, ahead of a multi-megawatt demonstration plant in the Mediterranean.

Mass Production Meets Energy Transition Urgency

Europe’s renewable energy buildout faces a storage bottleneck. The International Energy Agency estimates the world needs 120 terawatt-hours of long-duration storage by 2040—ten times current capacity. Onshore pumped hydro can’t scale fast enough due to geography, permitting, and environmental concerns.

Sizable’s modular design enables mass production impossible with land-based systems. Each installation is identical regardless of location, requiring only coastal waters deeper than 500 meters. The standardized approach dramatically reduces deployment time and cost uncertainty.

“Ocean depth is a practically unlimited resource, and Sizable Energy is leveraging it to deliver long-duration energy storage at a fraction of the cost of batteries,” said Bruce Leak, general partner at Playground Global and board member. The company targets €20 per kilowatt-hour—roughly one-tenth the cost of grid-scale batteries.

Sizable plans to begin commercial project development in 2026 at multiple global sites. The technology pairs naturally with offshore wind farms, sharing electrical connections to shore and reducing infrastructure costs. For coastal regions with deep waters, this could unlock gigawatt-scale storage without sacrificing land or fresh water.

you might also like

Fundraising 39 minutes ago

The European sports technology sector continues its robust growth trajectory, with French startups leading the charge in democratising elite athletic performance. Against this backdrop, Paris-based Kotcha has secured €3.5 million in funding to transform how everyday runners access professional-grade coaching. The round positions France as a key player in the rapidly expanding sports tech market, where digital platforms are reshaping traditional coaching models across Europe. Sports tech funding attracts European investors The funding round was led by Racine2, a Paris-based venture capital firm known for backing consumer technology companies across Europe. Racine2’s investment thesis centres on platforms that leverage technology to democratise access to premium services, making Kotcha a natural fit for their portfolio strategy. The firm has previously backed European startups that challenge traditional service delivery models through digital innovation. “Kotcha represents the perfect intersection of sports expertise and accessible technology,” explains a partner at Racine2. “Their approach to making elite running coaching available to amateur athletes addresses a significant gap in the European fitness market.” The investment reflects growing investor confidence in European sports technology companies that can scale across multiple markets whilst maintaining local relevance. Platform targets fragmented European fitness market Kotcha’s platform connects recreational runners with certified coaches through a digital interface that personalises training programmes based on individual goals and performance data. The startup differentiates itself from generic fitness apps by emphasising human expertise combined with data-driven insights, a approach particularly resonant with European consumers who value personalised service. The funding will primarily support international expansion across European markets, where Kotcha sees significant opportunity in countries with strong running cultures like Germany, the Netherlands, and the United Kingdom. “We’re not just building another fitness app – we’re creating a bridge between elite sports knowledge and everyday athletes,” states the company’s founder. The platform already serves thousands of runners across France and plans to launch in three additional European markets by 2025. This funding round signals investors’ growing appetite for European sports technology ventures that combine traditional expertise with modern accessibility. For the broader ecosystem, Kotcha’s success demonstrates how French startups can compete effectively in the global sports tech arena whilst maintaining their European identity.

Fundraising 39 minutes ago

The European food industry’s sustainability transformation is accelerating, driven by both regulatory pressure and genuine consumer demand. Against this backdrop, Mondra, a London-based platform tackling food supply chain emissions, has secured €11.8 million in Series A funding to expand its carbon management technology across Europe’s fragmented food sector. The round was led by AlbionVC and Planet A Ventures, two investors with distinctly different but complementary approaches to the European sustainability market. This investor combination signals growing confidence in food tech solutions that address both environmental impact and operational efficiency. Food emissions Series A attracts European sustainability specialists AlbionVC’s participation represents a strategic bet on B2B climate solutions within their established enterprise software thesis. The firm, which previously backed European success stories like Cazoo and Zopa, sees food supply chain optimisation as a massive addressable market ripe for digitisation. “Food companies are facing unprecedented pressure to demonstrate genuine sustainability credentials, not just marketing speak,” noted an AlbionVC partner familiar with the deal. Planet A Ventures brings complementary expertise as one of Europe’s most active climate-focused VCs. Their portfolio approach targets solutions addressing specific carbon reduction challenges, with food systems representing one of their core investment themes. The firm’s backing suggests Mondra’s technology has demonstrated quantifiable emission reductions rather than theoretical projections. This investor mix—traditional enterprise VC plus climate specialist—reflects the maturation of European sustainability investing. Companies like Mondra no longer need to choose between commercial viability and environmental impact; the best solutions deliver both. European food sector embraces digital carbon management Mondra’s platform addresses a distinctly European challenge: managing sustainability compliance across multiple jurisdictions whilst maintaining operational efficiency. Unlike US food companies operating within relatively uniform regulations, European food businesses navigate a complex web of national and EU-level requirements, from farm-to-fork strategies to upcoming corporate sustainability reporting directives. The startup’s technology enables food companies to track, measure, and reduce emissions across their supply chains through real-time data integration and automated reporting. This approach resonates particularly well with European food manufacturers who face increasingly stringent sustainability disclosure requirements under incoming EU legislation. “We’re not just measuring emissions—we’re helping companies fundamentally rethink their supply chain decisions to achieve genuine reductions,” explains Mondra’s CEO. “European food companies understand that sustainability isn’t optional anymore; it’s becoming a competitive advantage.” The funding will primarily support product development and European market expansion, with plans to establish operations in key food manufacturing hubs including Germany, France, and the Netherlands. This geographic strategy acknowledges that European food supply chains are inherently cross-border, requiring solutions that work seamlessly across different regulatory frameworks. Mondra’s Series A reflects broader momentum in European food tech, where regulatory tailwinds and corporate sustainability commitments are creating genuine market demand for solutions that deliver measurable environmental impact alongside commercial returns.

Sizable Energy ocean energy storage system showing underwater pumped hydro technology with seabed reservoirs and floating surface infrastructure
Fundraising 8 hours ago

Italian startup Sizable Energy secures €7.4M led by Playground Global to commercialize offshore pumped hydro system storing gigawatt-scale power underwater.

Subscribe to
our Newsletter!

Stay at the forefront with our curated guide to the best upcoming Tech events.