More than half of Helsinki’s heating comes from coal. But Finland has decided to stop using coal for energy purposes in 2029.

In addition, both the capital and the country as a whole aim to become carbon neutral by 2035. That is why Helsinki recently hosted the international competition Helsinki Energy Challenge. The purpose was to get suggestions on how the city can be heated without coal and with as little biomass as possible.

The interest in the competition was great. Over 250 entries from a total of 35 different countries were submitted.

On Tuesday, it was announced that four entries have been named winners. Or actually five grants, because one was awarded a special “recognition prize”.

“A wide range of solutions”

The four winning entries are called Hive, Beyond Fossils, Smart Salt City and The Hot Heart. The recognition award went to CHP Consumers to Heat Produces because the grant provided an “eye-opening description of the diversity of the heating challenge and relevant stakeholders.”

Behind Smart Salt City are the Swedish companies Salt X Technology and Rebase Energy. Their idea is a new kind of energy storage that is controlled with artificial intelligence based on forecasts of energy supply and energy needs. This is combined with existing technology, mainly heat pumps.

Salt X energy storage is based on changes between slaked and burnt lime, calcium hydroxide and calcium oxide, respectively. Ny Teknik recently told about the company’s plans to build a pilot plant in Stockholm to test the technology for recharging and discharging the energy storage.

The company has developed a special nano-coating that surrounds the calcium oxide particles. In this way, the material should not clump together in the bearing and have a long service life.

The five winners of the Helsinki Energy Challenge will share one million euros. Team Hive will receive 350,000 euros and CHP Consumers to Heat Producers will receive 50,000 euros while the others will receive 200,000 each.

– We did not expect the competition to provide a solution that makes the whole puzzle go together. Instead, we now have in our hands a wide range of solutions that can help not only Helsinki but also other cities that are looking for heating solutions, says Helsinki Mayor Jan Vapaavuori.

“Solutions must be easy to change”

The organizers state that electric heating solutions were a common theme in many of the competition entries. Emission-free electricity is easier to produce than emission-free heat, so several of the solutions lean towards heat pumps.

One lesson that the organizers have learned is that the heating systems of the future must be flexible.

– Solutions that are put into operation today must be easy to change, says Jan Vapaavuori.

But whether some of the winners’ ideas will actually be realized in Helsinki is unclear.

– The exact investments are an open question, says Jan Vapaavuori.