A significant milestone in clean energy innovation has just been achieved in Finland — the world’s largest sand battery is now operational, offering a new, sustainable solution to one of the biggest challenges in the renewable energy transition: long-duration energy storage.
At Fourblue, we’re always keeping a close eye on the technologies reshaping the energy landscape, not only for their environmental impact but for the exciting career opportunities they unlock across the clean energy sector.
What Exactly Is a Sand Battery?
Unlike conventional batteries that use chemical processes to store electricity, sand batteries are thermal energy storage systems. Developed by Finnish start-up Polar Night Energy, these systems use low-grade sand as the storage medium, heated to temperatures of up to 600°C using excess renewable electricity — often from solar or wind. This heat is stored for days or even months and can be released to provide district heating or, with the right systems, be converted back into electricity.
What makes sand an ideal storage medium? It’s cheap, readily available, non-toxic, and highly efficient at retaining heat over time. It also avoids many of the resource and environmental issues associated with lithium-ion and other chemical batteries.
A World First in Pornainen
Polar Night Energy’s new installation in Pornainen, southern Finland, is now the largest sand battery ever built. In partnership with Finnish energy provider Loviisan Lämpö, the battery can store 1 megawatt-hour of energy and deliver 100 kilowatts of thermal power to the local district heating network. This is enough to provide hot water and heating to nearby homes during Finland’s notoriously cold winters — all using surplus green energy.
The project builds on their previous, smaller-scale pilot in the town of Kankaanpää, and represents a clear move toward commercial-scale application of this emerging technology.
Why Sand Batteries Matter
As Europe continues its push toward net-zero, one of the most persistent challenges remains: how do we store excess renewable energy, especially in seasons when solar or wind generation is low?
Traditional batteries are often too costly or limited in duration for storing energy over days or weeks. Sand batteries offer a compelling alternative. According to Euronews Green, they could prove especially valuable in providing year-round energy resilience, storing summer solar power for use in winter months — a potential game-changer for colder regions.
They also support decentralised heating systems, meaning communities can benefit from clean energy locally, reducing reliance on fossil fuels and increasing energy security.
Creating New Opportunities in Clean Tech
At Fourblue, we know that groundbreaking technologies like this don’t just change how we generate and store energy — they also reshape the job market. As thermal storage solutions scale up, we anticipate growing demand for professionals across:
– Mechanical and thermal engineers
– Energy systems and grid integration specialists
– Construction and commissioning project managers
– Environmental and sustainability consultants
– Software and controls engineers
Whether you’re working in R&D, infrastructure delivery, or regulatory strategy, there’s a wealth of opportunity for talent ready to lead the clean energy transition.
What’s Next?
Sand batteries may seem like a simple concept, but they’re proving to be a crucial missing piece in the global energy puzzle. As we move toward a more electrified, decarbonised future, low-cost, scalable storage solutions like this will be essential for making the most of our renewable resources.
If you’re looking to be part of this transformative shift — whether in thermal storage, smart grids, or green infrastructure — Fourblue is here to connect you with the right opportunities – get in touch with the team today.