Interest in solar energy in Kivikko
The Helsingin Auringonvalo apartment building project planned for Kivikko aims to make extensive use of solar power.
"In general, it has not been worthwhile for housing companies to invest in solar power generation for two reasons: the electricity consumption of housing company systems is very low, especially in buildings utilising district heating, and electricity consumption is concentrated in the winter months, while solar power generation is at its highest during the summer months," says T2H Project Manager Miikkael Soukka responsible for the project.
The Kivikko building is heated and cooled by geothermal heating, which is powered by the company's own solar power plant. The difference between peak production and peak consumption is made up by the fact that electricity generated by the solar power plant can also be fed directly into homes and electric car charging without passing through the grid. This is possible because the property has only one electricity point of use and one electricity contract.
"The combined effect of solar power and the electricity system on residential costs is significant. You could say that our site is self-sufficient in space heating," Soukka says.
Positive energy buildings produce more energy than they consume
The EXCESS positive energy apartment building in Kalasatama, completed in 2023, aims to produce more energy per year than it consumes. Energy from local sources is used for heating, air conditioning and domestic hot water.
The Kalasatama site is one of four pilot projects built in different climate zones across Europe. The other sites are located in Austria in a continental climate, in Belgium in an Atlantic coastal climate and in Spain in a Mediterranean climate.
In the Kalasatama positive energy apartment building, electricity is produced by solar panels on the façade and roof. In addition to the heat from the photovoltaic thermal panels further developed in the context of the project, the heat will come mainly from thermal wells at a depth of 400–600 metres, with some cooling and exhaust air, all utilising heat pumps. Intelligent control and optimisation of the system is also important in order to maximise the use of local sources on site.
"The site has performed well technically, and measurements show that energy positivity in heating can be achieved once the solar energy installations are completed. Challenges have been posed in particular by the permitting processes for the panels and delays in installation, but on the other hand, the development process regarding the system has brought about improvements to the efficiency of the final solutions," says Specialist Researcher Mia Ala-Juusela from VTT Technical Research Centre of Finland, who was involved in the project.
0CO2 project aims for operating energy carbon neutrality
The 0CO2 project, completed in 2025 in Verkkosaari, has developed an operating model for the carbon-neutral production of operating energy. The 0CO2 project is compliant with energy efficiency class A and produces heating based on a hybrid model: a smart system that switches between geothermal and district heating according to which option has the lower carbon footprint at any given time. The project already meets and exceeds the City of Helsinki's low-carbon targets.
In geothermal heat production, conventional heat wells are complemented by heat-generating energy piles used in foundations, the potential of which is being explored in marine infill areas.
Solar power also plays a role. One of the buildings has a conventional solar power plant on its roof, and another has a shared-use space that is almost the size of the roof glazed with photovoltaic glass panels.
"We are still in the early stages, meaning that we cannot provide a comprehensive assessment until we have production data for the different seasons, but the interest in the property has been exceptionally high: the building was quickly rented out, the common areas have been popular and the heating system settings have been fine-tuned to keep the conditions even in all apartments," says Roope Tammi, CEO of Suomen Keskuskodit, the company responsible for the project.
Part of the Re-Thinking Urban Housing Programme
Launched in 2009, the Re-Thinking Urban Housing Programme is a City of Helsinki programme aimed at improving the quality of apartment building living. To this end, the programme provides developers with opportunities to try out new solutions and receive support from City specialists. For residents, the programme offers new housing alternatives and examples of how to improve the quality of apartment building living.
To date, more than 40 projects of different occupancy types have been carried out under the Re-Thinking Urban Housing Programme. The completed projects emphasise adaptability, community cohesion, affordability and low-carbon housing, among other things.
