Heat Battery – Utilization of industrial side streams for sustainable energy storage

Energy storage is one of the key elements as well as one of the most challenging problems of the green transition. Variable renewable energy sources (VRES) such as wind and solar power are intermittent and non-dispatchable, which has led to an increased need for storage technologies. Therefore, sustainable, scalable and inexpensive energy storage solutions need to be implemented, to capture and store excess energy during high VRES output. This helps balancing supply and demand and enhances the utilization of renewable energy resources.


Project information

Project duration


Funded by

Other Finnish

Project funder

Just Transition Fund (JTF) via Council of Oulu Region City of Oulu

Funding amount

359 994 EUR

Project coordinator

University of Oulu

Contact information

Contact person

Project description

The Lämpöakku (Heat Battery) project aims at developing energy efficient, profitable, modular, scalable, and sustainable energy storage technology based on heating of inorganic materials from secondary sources. In the Heat Battery concept, the excess electricity generated by VRES can be stored as high temperature thermal energy (>500°C), to be used later for heating of solids and gases as well as for production of steam in industrial applications on-demand. Additionally, the thermal energy can be used as heat source for district heating or for heating of houses and commercial greenhouses, as well.

The Heat Battery concept generates options for creating new businesses and jobs related to the construction and operation of heat batteries as well as for the generation of thermal energy for the customers. Additionally, the heat battery enables the energy sector to capture excess VRES generation, which will also help reducing electricity price volatility. As the Heat Battery is based on industrial side stream materials, this concept will also enhance the integration of the energy industry and the circular economy.

In this joint project of University of Oulu and Oulu University of Applied Sciences, the characteristics and thermal properties of industrial side products will be studied in detail. The operation of the Heat Battery will be modelled at different levels, i.e., at the level of a piece of material, at the battery level and at the systemic level of the energy production network.

Participating in the project: