Estonian supercapacitor manufacturer Skeleton Technologies has raised more than $100 million in a Siemens-led funding round, lifting its valuation above $1 billion and making it a unicorn. SmartCap invested in Skeleton Technologies through its Green Fund in 2025.
Skeleton Technologies plans to use the new funding primarily to expand manufacturing in the United States and research and development activities in Silicon Valley. The expansion comes as growing adoption of artificial intelligence drives demand for energy storage solutions in data centres.
“Estonia is known for its digital and software success stories, but Skeleton shows that we are also developing world-leading critical hardware that powers the AI revolution globally,” said Patrik Louko, CEO of SmartCap. “When one of the world’s largest industrial companies leads an investment round and builds its data centre offering around Estonian technology, it sends a strong signal to international investors and the whole world takes notice. Achievements like this raise the profile of Estonia’s technology sector, attract new capital to the country and give other founders the confidence to think big. SmartCap’s ambition is to back companies that can grow from Estonia into global market leaders, and Skeleton is a great example of what that looks like.”
Skeleton’s energy storage solutions use supercapacitors to manage rapid fluctuations in data centre power demand and make more efficient use of existing electrical infrastructure. According to the company, its technology can deliver energy savings of up to 40% while improving the performance of graphics processing units (GPUs).
The new investment will also deepen the existing strategic partnership between Skeleton and Siemens. Siemens will gain exclusive rights to sell Skeleton’s solutions in the data centre market and integrate them into its electrical infrastructure portfolio. This will give Skeleton access to a broader customer base through Siemens’ global sales network.
SmartCap’s Green Fund aims to improve access to capital for high-growth Estonian green technology companies and support their expansion into international markets. The Green Fund has now reached the end of its investment period. The SmartCap Green Fund is financed by the European Union’s NextGenerationEU Recovery and Resilience Facility (RRF).
