Solar energy has emerged as a viable alternative in the Nordic energy markets due to price reductions. Now 
In the Helsinki Eko-Viikki housing area, nine properties have been equipped with solar heating systems. (Photo credit: Helen Oy)researchers from Aalto University contend that more than 80% of heating energy for Finnish households could be derived from solar energy systems.
The amount of solar heat obtained for heating households, assuming excess energy is stored for use during cold periods, was calculated. The assessment included three community-sized solar heating systems configurations for cold climate: (I) a heat pump connected to two tanks in parallel, using charged borehole storage, (II) a heat pump connected between two tanks, using charged borehole storage to directly charge the lower temperature tank, and (III) two heat pumps used in series, one between the tanks and the other between the lower temperature tank and ground. The results depended on how the heat pumps, the water storage tanks and the borehole storage were used together.
"In Finland, more than 80% of the energy consumption in households goes to heating buildings and water, and this is on the increase. Solar energy offers economically sensible solutions for the collection of energy for this purpose, and for the reduction of carbon dioxide emissions, especially in southern Finland where the majority of the population lives," says Kai Sirén, Professor at Aalto University.
Renewable energy could be used to cover 53–81% of annual domestic heating energy consumption depending on the technical implementation method. This finding is also valid for Sweden, Norway and other locations at the same latitudes.
