Innovation

Polar Night Energy's innovation, the sand battery, “is a high temperature thermal energy storage that uses sand or sand-like materials as its storage medium. It stores energy in sand as heat.” The idea of the innovation is that as a high-power and high-capacity reservoir, it stores excess wind and solar energy as heat to be used to warm up households or, for example, to provide hot steam for industries often using fossil-fuel as an energy source.

The purpose for the sand battery is to improve the efficiency of renewable energy production and taking it to the next level. It ensures that when the surplus of clean energy is massive, it still can be used, even after months of storing it. To simplify, the sand product used is in an insulated silo charged with electrical energy which is transferred to the heat storage through pipes. What is significant in terms of sustainability is that the preferable material for the storage material is always local excess sand or sand-like material not suitable for the construction industry. The sand can be heated to 600 degrees Celsius even up to 1000 Celsius, well above the storage capability of water tanks with the limit of the boiling point of water. When businesses and industries operating in a variety of sectors are in need of heating the energy is unloaded through pipes. Thus, the idea to heat sand and store it is not new but the way PNE is doing and commercializing it in this scale is.

Inspiration

One day on a coffee break the founders of Polar Night Energy, Tommi Eronen & Markku Ylönen wondered if it would be possible to construct an innovative hippie commune that uses only solar power as a source of heating and energy. “They started talking and thinking about could they somehow build an energy sufficient and affordable student housing like an off the grid, kind of a thing”, Miika Peltola, communications specialist at Polar Night Energy explained in our interview. He continued by explaining what they wanted to contribute to: “But they thought that one of the biggest problems would be how to store energy for the housing. And then they started thinking about storing energy and storing electricity, and then they came up with the idea of storing heat because storing big amounts of heat is a bit easier and cheaper than storing electricity." And this is how sand batteries by Polar Night Energy were born. 

Tommi and Markku, the two Tampere University of Technology students used their MSc. theses and Markku’s PhD to convert the question into a concrete project. As a result, in 2018 Polar Night Energy, answering to the world’s urgent need on more sustainable, attainable, and clean energy, was founded. And the solution, sand battery, ended up becoming a much wider climate change mitigating solution than the originally invented idea benefitting a hippie commune was. Today, sand batteries are the perfect solution to solve the world’s increasing energy shortages.

Overall impact

Although the company is at its early stage of developing its business it has established two projects in Finland. The first is a commercial heat storage connected into Vatajankoski company’s energy utility heating network in Kankaanpää. In addition, they have launched a pilot plant connected to Tampere’s heating network. Polar Night Energy's long-term objective is to provide stable, affordable and clean energy seasonal heat storage solution for everyone from large metropolitans to distant villages all around the world. In addition, it will provide sustainable solutions to different businesses and industries.

The innovation could solve the year-round supply issue of green energy. In Finland, where the solution was innovated, most of the gas comes from Russia and thus, the war in Ukraine has underlined the need for new renewable energy solutions. With sand batteries Polar Night Energy answers to the need of heating during long and cold winters by low-cost and low-impact way in Finland, and possibly in other Nordic countries. But most of all, storing renewable energy for longer periods of time is a chance for a comprehensive advancement for industries, such as food and drink, textiles and pharmaceuticals, using heat derived from burning fossil fuels.

Business benefit

The innovation of sand batteries is still new and therefore the company wants to concentrate all efforts into the innovation ensuring the creation of the most efficient energy storage. The sand battery is so far the only product the company has developed. 

With a space offered by city of Tampere, Polar Night Energy was able to start the first pilot in Hiedanranta area. After this, the company was quickly given a possibility to start the world’s first commercial sand-based thermal energy storage in Kankaanpää. This was a changing point in regards of the growth possibilities of the company, as the innovation started to raise an enormous amount of international interest. After BBC write a story of the plant in summer 2022, the company has been featured in almost 1000 news articles in different medias, including televisions of Japan, China, and France, among others. 

As the company is still in the starting period of its lifetime, the innovation will most expectedly result in a world-wide network, as according to the company’s media report approximately 3.5 billion people are at the potential reach of the media visibility. In addition to the media coverage, the company has been granted with an Honorary Certificate in the category of The High Potential Carbon Handprint Innovation in the International Carbon Handprint Award, which also acts in means of raising interest towards the company. This visibility has brought contacts and prospects of investments to the company which has led the organization to consider enlarging their team in the upcoming months. 

Social and environmental benefit

The sand battery technology provides heat to citizens while using a renewable source of energy. It stores energy that can be used in buildings and industries that rely on environmentally harmful energy sources. In contrary to most energy sources, the batteries don’t suffer from energy excess, as they are able store it for later use. In a difficult climate like Finland this innovation is therefore extremely beneficial as it can ensure that households and other buildings get uninterrupted heat all year long. 

Because of their main component, sand batteries are an affordable energy source on a large scale, enabling even developing societies to get access to energy, which contributes to creating a more sustainable world. The silos used to store the energy are very large and can be accused of visual pollution of landscape like the wind turbines. However, sand battery silos can be constructed underground or into existing mining craters, which limits their impact on the environment. Furthermore, when situated strategically, the excess heat created by the silos could be utilized in greenhouse projects among others.  

More traditional batteries use lithium, which is extremely polluting, and that is without mentioning the damage caused by drilling and the often-painful working conditions, the harmful chemical used in the process and the hazardous waste resulting. The use of sand batteries is therefore an excellent alternative both environmentally and socially. 

Interview

Miika Peltola, COMMUNICATIONS SPECIALIST