Polar Night Energy
Finland has just switched on an industrial-scale sand battery in the southern town of Pornainen, where it will replace an aging woodchip plant as the main source of heating for the municipality. Expected to cut local heating-related carbon emissions by up to 70%, the facility now holds the title of the largest sand battery in the world.
Built by the Finnish company Polar Night Energy – the same firm that developed the world’s first commercial sand battery a few years back – the system measures around 42 ft (13 m) tall and 50 ft (15 m) wide. It can store up to 100 MWh of thermal energy with a round-trip efficiency of 90%. That’s roughly 10 times the capacity of the original prototype, enough to provide the town with a full week of heating.
A Solution for Energy Storage Challenges
Thermal Energy Storage (TES) like this is especially valuable in countries such as Finland, which rely heavily on intermittent solar and wind power while facing fluctuating seasonal energy demands. The sand battery absorbs surplus electricity when it’s cheap and plentiful, storing heat that can remain viable for months. This stored energy can then be tapped during peak demand to stabilize the grid.
How the Sand Battery Works
The system uses excess renewable electricity to heat sand inside a large, insulated silo through a closed-loop air pipe system, reaching temperatures of up to 1,112 ºF (600 ºC). The sand retains this heat for extended periods. When needed, cooler air is pushed through the silo, absorbing the stored heat and reaching temperatures of around 752 ºF (400 ºC). That hot air can then generate steam for industry or heat water for municipal heating through a heat exchanger.
Polar Night Energy
Unlike traditional batteries, this setup doesn’t supply electricity directly. However, Polar Night Energy is exploring ways to convert the stored thermal energy back into power, potentially through steam turbines.
Already Delivering Results
Though officially launched this week, the battery has been running since June and has already outperformed efficiency expectations during its initial optimization phase. Key buildings in Pornainen, including the town hall, are now heated by this system.
Polar Night Energy
Looking ahead, the giant sand battery is expected to play a pivotal role in helping Pornainen reach carbon neutrality, while serving as a model for other municipalities in similar climates to adopt this large-scale, sustainable technology.
Read the original article on: New Atlas
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