Imagine a battery that stores renewable energy not in fancy chemicals, but in ordinary sand. A Finnish town is about to make this a reality with the world’s biggest “sand battery.”
Storing Sunshine and Wind:
- Located in Pornainen, southern Finland, this 100 MWh thermal energy storage unit will harness surplus solar and wind power.
- By eliminating oil from the district heating network, it’s projected to cut the town’s emissions by nearly 70%.
Innovation on a Large Scale:
- This project by Polar Night Energy marks a significant step in scaling up sand battery technology.
- It follows the success of their initial, smaller design tested in Kankaanpää in 2022.
Sand: A Surprisingly Roomy Energy Bank:
- Sand’s ability to store heat effectively makes it ideal for harnessing the full potential of renewable energy sources like solar and wind.
- Unlike lithium batteries, sand-based storage boasts affordability and the capacity to hold vast amounts of energy.
How Does it Work?
- The core principle is deceptively simple. Sand is heated using excess electricity via resistive heating, where an electric current generates heat through friction.
- This hot air is then circulated and stored within the container through a heat exchanger.
- Remarkably, the sand retains heat at around 500°C for days or even months, providing a reliable source of clean energy during winter.
- When needed, the battery releases the stored heat, warming water in the district heating network, benefiting homes, businesses, and even the local swimming pool.
Pornainen’s Path to Clean Energy:
- Polar Night Energy has refined their charging algorithms, allowing for a larger scale implementation in Pornainen.
- The battery will integrate with the network of Loviisan Lämpö, the district heating provider.
Environmental Benefits:
- This project aligns perfectly with Pornainen’s goal of carbon neutrality.
- The sand battery is expected to:
- Eliminate the town’s dependence on oil entirely.
- Reduce woodchip burning by 60%.
- Offset an estimated 160 tonnes of carbon dioxide emissions annually.
- Provide thermal energy storage equivalent to nearly a month’s heat demand in summer and a full week in winter.
Sustainability Concerns and Solutions:
- While sand seems abundant, its widespread use in construction raises concerns.
- To address this, the Pornainen project utilizes crushed soapstone – a sustainable by-product from a local fireplace manufacturer.
Global Potential:
- Polar Night Energy envisions large-scale sand battery deployments worldwide.
- Their goal? Building “a hundred times larger storages around the world as fast as possible.”
This pioneering project in Finland demonstrates the exciting potential of sand battery technology. By harnessing the power of a readily available material, communities can embrace a cleaner and more sustainable energy future.
