Even now, we are wasting money. Buildings and our built environment are constantly losing heat that could be utilized. This is called waste heat.

The amount of waste heat that can be recovered is not clear, but according to various studies, in Finland alone, excess heat from industry is estimated to be worth hundreds of millions of euros. In summer, the extra heat is even problematic.

How is waste heat recovered? There are already technological solutions to this. The biggest challenge in exploiting the extra heat so far has been the problem of seasonal mismatch. This means, that the heat that is naturally generated in the summer and the available excess heat from buildings and the built environment is being lost. And in the winter, when there are freezing temperatures in the Nordic countries, the heat costs the earth.

Seasonal storage is the solution to the problem of mismatch 

There is a solution to the problem of seasonal mismatch of thermal energy. The solution is seasonal storage (STES). With seasonal storage, it is possible to store the excess heat generated during summer and utilize it in the winter. 

There is a growing interest in the seasonal storage of thermal energy. It can provide significant savings in winter heating costs. nollaE has already designed energy systems using seasonal storage, for instance, the Tower of Skanssi apartment building and the Turun Toriparkki underground parking energy system currently under construction. There the solar thermal energy is stored in the ground during the summer.

The heat stored in the winter is used for heating the premises and at the same time, it can be utilized, for example, for ice-melting outdoors.

Nikolas Salomaa, CEO of nollaE, talking about waste heat and seasonal thermal energy storage at Shift Business Festival 2019.

Nikolas Salomaa, CEO of nollaE, talking about waste heat and seasonal thermal energy storage at Shift Business Festival 2019. Picture: Julius Töyrylä

Synergies by re-engineering energy flow

There is a huge amount of usable thermal energy around us that is currently being wasted. Buildings, surrounding infrastructure and industry generate heat that could be recovered for later use or alternatively reused.

To put it simply, a building uses energy for heating and the building next to it uses cooling. By taking a closer look at the different energy needs of these buildings, there is scope for mutually cost-effective re-engineering of energy flow, optimum energy efficiency, and synergies.

The re-engineering of energy flow will revolutionize energy consumption and enable almost zero-energy property management. At the same time, carbon dioxide emissions from buildings can be minimized. But it requires a change of mindset from both property owners and developers, construction companies, the public administration, and the energy industry. First steps in the right direction have been taken, but much remains to be done.