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Finland’s Giant Sand Battery Is Heating Homes — And Sparking Big Ideas

Erika Willitzer
2 days ago
2 min read

In the small town of Pornainen, Finland, residents are staying warm in winter thanks to something totally unexpected: a giant tank of sand.

Not a metaphor. Actual sand.

This isn’t a quirky science experiment — it’s a fully operational thermal energy storage system developed by Finnish startup Polar Night Energy, and it’s changing the way small towns think about sustainability.

\What Is a Sand Battery?

Here’s the magic: when renewable electricity (like solar or wind) is abundant, it’s used to heat up sand inside a massive insulated silo. That sand can reach temperatures of over 600°C (1,112°F) and hold the heat for months.

When the town needs hot water or heating, cool air is blown through the sand, absorbing the stored heat. That hot air is then used to warm water for homes and offices — no combustion, no emissions, no fossil fuels.

It’s like a giant thermos, but for your entire community.

Why It’s a Big Deal

According to Polar Night Energy, this sand battery stores up to 100 megawatt-hours of energy — enough to heat the entire town for a week. And it’s already helping reduce heating-related emissions by nearly 70%.

That’s not just impressive. It’s transformative.

“Combustion is not a sustainable option for the climate or the environment,” says Liisa Naskali, COO of Polar Night Energy. “This project is a powerful example that effective solutions for mitigating climate change do exist.”

What Small Towns Can Learn

This isn’t just a Finnish success story — it’s a blueprint for small towns everywhere. Here’s why it matters:

Affordable materials: Sand is cheap, safe, and widely available.
Long-term storage: Unlike batteries that degrade over time, sand can hold heat for months.
Scalable impact: This system is already heating homes, offices, and public buildings — all without burning a single drop of fuel.

Inspiration for Small Town Wow

If a town north of Helsinki can heat its buildings with sand, what could your town do with the right tools and vision?

This story is a perfect fit for Small Town Wow’s mission: empowering rural communities with smart, sustainable solutions. Whether it’s sand batteries, solar co-ops, or community-led energy projects, innovation doesn’t have to be flashy — it just has to work.

Want to learn more? Visit Polar Night Energy’s official site or check out MSN’s coverage of the sand battery.