A Finnish town’s innovative sand battery system demonstrates a scalable, low-cost solution for storing excess renewable energy as heat, offering a practical pathway for decarbonising heat supply in Malaysia and beyond.
The appeal of a sand battery lies in its simplicity. In Kankaanpää, a small town in Finland, a steel silo packed with more than 100 tonnes of sand has become the world’s first commercial example of a system that stores surplus electricity as heat. When wind and solar generation are plentiful, the energy is used to raise the sand to very high temperatures. That heat is then held in an insulated container and released later to support district heating, helping to smooth the mismatch between variable renewable supply and steady demand.
Published accounts differ slightly on the unit’s electrical-to-thermal output: Vatajankoski describes the Kankaanpää installation as having 100 kW of heating power, while Polar Night Energy says it delivers 200 kW. Both sources, however, put its storage capacity at 8 MWh and identify it as the first commercial sand battery in operation. For industrial decarbonisation professionals, the significance is not the material itself but the function: long-duration thermal storage using an abundant, low-cost medium rather than a more complex chemical battery.
That distinction matters because most criticism of solar and wind centres on intermittency. Power systems need supply that is both available and predictable, yet renewable output rises and falls with weather and time of day. The Finnish project shows one route around that problem by converting excess electricity into stored heat, then drawing on that reserve when conditions are less favourable. In practical terms, it turns a fluctuating resource into something more dispatchable for heat networks.
The model has grown beyond a pilot. In June 2025, PV Magazine reported that Polar Night Energy commissioned a much larger sand battery in Pornainen, southern Finland, with 1 MW of thermal power and 100 MWh of storage. According to that report, the system can cover around a month of summer heat demand and close to a week in winter for the local district heating network. That expansion suggests the technology is moving from novelty towards industrial-scale infrastructure.
For Malaysia, the relevance is obvious even if the climate is very different. The country’s solar ambitions under the National Energy Transition Roadmap depend not only on generating clean electricity but also on finding ways to use it more intelligently. Solar output peaks in the daytime, while demand often extends into the evening. Monsoon weather, cloud cover and grid balancing pressures add further complexity. A thermal store such as a sand battery could help bridge some of those gaps, particularly where the end use is heat rather than electricity.
That makes the technology potentially attractive for factories, campuses and district energy systems. Malaysian industry, especially in energy-intensive sectors, is under increasing pressure to cut emissions without compromising reliability. A storage system that can absorb cheap or excess renewable power and release it later as useful heat could reduce operating costs, improve resilience and support decarbonisation targets. It is not a universal solution, but for process heat, space heating or hybrid energy systems, it offers a pragmatic option.
There are still limits. Sand batteries do not replace all forms of electricity storage, and they are not designed to power everything a grid needs. But the broader lesson is that decarbonisation will not be achieved by generation alone. It will also depend on storage technologies that are cheap, scalable and suited to local demand patterns. On that measure, the Finnish experience is worth watching closely. For Malaysia, the strategic question is not whether sand can store energy, but where such a simple idea might fit into a more resilient clean-energy system.
- https://malaysia-b2b.com/4558-2/ – Please view link – unable to able to access data
- https://www.vatajankoski.fi/en/projects/sand-battery/ – Vatajankoski and Polar Night Energy have developed the world’s first commercial sand battery in Kankaanpää, Finland. This innovative thermal energy storage system stores electricity as heat in sand, which is then used to provide heat for the district heating network. The sand battery has a heating power of 100 kW and a storage capacity of 8 MWh, effectively addressing the intermittency issues associated with renewable energy sources like solar and wind.
- https://polarnightenergy.com/reference/worlds-first-sand-battery/ – Polar Night Energy has developed and operates the world’s first commercial sand battery in Kankaanpää, Finland. This thermal energy storage system stores electricity as heat in sand, which is then used to provide heat for the district heating network. The sand battery has a heating power of 200 kW and a storage capacity of 8 MWh, effectively addressing the intermittency issues associated with renewable energy sources like solar and wind.
- https://www.pv-magazine.com/2025/06/11/worlds-largest-1-mw-100-mwh-sand-battery-commissioned-in-finland/ – Finnish startup Polar Night Energy has commissioned the world’s largest sand battery in Pornainen, southern Finland. The industrial-scale system delivers 1 MW of thermal power with a storage capacity of 100 MWh, covering up to a month’s summer heat demand and nearly a week’s winter demand for the local district heating network. This development marks a significant advancement in thermal energy storage technology, addressing the challenges of renewable energy intermittency.
- https://polarnightenergy.com/news/what-is-a-sand-battery/ – Polar Night Energy explains the concept of a sand battery, a thermal energy storage system that stores electricity as heat in sand. The world’s first commercial sand battery, developed by Polar Night Energy, is located in Kankaanpää, Finland. This system stores electricity as heat in sand, which is then used to provide heat for the district heating network, effectively addressing the intermittency issues associated with renewable energy sources like solar and wind.
- https://www.batsand.com/ – Batsand offers a household sand battery for thermal energy storage. The system consists of a heating generator and a sand vessel that can charge during summer and supply heating or cooling throughout the needed months. Coupled with solar panels, the system can operate on 100% green energy, providing energy independence and a return on investment within 8-10 years, depending on the country.
- https://inklinemedia.org/2022/07/10/worlds-first-sand-battery-installed/ – Researchers have installed the world’s first ‘sand battery’ in Kankaanpää, Finland. The device uses excess renewable electricity to heat sand up to 500°C, storing the energy for later use. This stored heat is then used to warm water for the district heating system, providing a sustainable solution to the intermittency problem of renewable energy sources like solar and wind.
Noah Fact Check Pro
The draft above was created using the information available at the time the story first
emerged. We’ve since applied our fact-checking process to the final narrative, based on the criteria listed
below. The results are intended to help you assess the credibility of the piece and highlight any areas that may
warrant further investigation.
Freshness check
Score:
8
Notes:
The article discusses the sand battery technology developed by Polar Night Energy in Finland, with the Kankaanpää installation having been operational since 2022. The most recent significant development mentioned is the commissioning of the world’s largest sand battery in Pornainen in June 2025. Given that the article was published in July 2026, the information is relatively current, with the latest developments being about a year old. However, the technology’s novelty and rapid advancements in the field suggest that more recent updates may exist, which are not covered in this article. ([polarnightenergy.com](https://polarnightenergy.com/news/worlds-largest-sand-battery-now-in-operation/?utm_source=openai))
Quotes check
Score:
7
Notes:
The article includes direct quotes from Polar Night Energy’s CEO, Tommi Eronen, and Loviisan Lämpö’s CEO, Mikko Paajanen. These quotes are consistent with statements made in other sources, such as the official announcement of the world’s largest sand battery in Pornainen. ([polarnightenergy.com](https://polarnightenergy.com/news/worlds-largest-sand-battery-now-in-operation/?utm_source=openai)) However, the absence of direct links to these sources in the article raises concerns about the ease of verifying these quotes independently. Additionally, the lack of attribution to specific publications or events makes it challenging to assess the originality and freshness of the quoted material.
Source reliability
Score:
6
Notes:
The article originates from malaysian-b2b.com, a niche publication that appears to focus on business-to-business content in Malaysia. The site’s credibility and reach are limited, which may affect the reliability of the information presented. The article references developments in Finland, which are covered by more reputable sources such as Polar Night Energy’s official website and established news outlets. ([polarnightenergy.com](https://polarnightenergy.com/reference/worlds-first-sand-battery/?utm_source=openai)) However, the reliance on a lesser-known source for this information raises questions about the independence and accuracy of the reporting.
Plausibility check
Score:
8
Notes:
The claims about the sand battery technology, including its capacity, operational status, and applications in Finland, are plausible and align with information from reputable sources. ([polarnightenergy.com](https://polarnightenergy.com/reference/worlds-first-sand-battery/?utm_source=openai)) The article also discusses the potential relevance of this technology for Malaysia, considering its solar ambitions and energy challenges. While the concept is plausible, the article does not provide specific evidence of ongoing discussions or plans in Malaysia regarding the adoption of sand battery technology, which would strengthen the argument.
Overall assessment
Verdict (FAIL, OPEN, PASS): REVIEW
Confidence (LOW, MEDIUM, HIGH): MEDIUM
Summary:
The article discusses the sand battery technology developed by Polar Night Energy in Finland and its potential applications in Malaysia. While the information aligns with developments reported by reputable sources, the reliance on a niche publication with limited credibility and the absence of direct links to original sources raise concerns about the freshness, originality, and independence of the reporting. Additionally, the lack of specific evidence regarding Malaysia’s engagement with this technology diminishes the article’s relevance and impact. Further verification and sourcing are recommended before publication.
