Solar Energy

Heat and electricity from the sun

The solar energy reaching Finland from the sun annually amounts to 1 000 kWh per square metre. In just an hour the world receives enough energy in the form of solar radiation to meet all of humanity’s energy needs for a year.

Solar energy can be exploited passively or actively. Passive solar energy involves exploiting heat and light from the sun directly without using any appliances to convert it to other forms of energy. Active solar energy involves transforming solar radiation into electricity using solar panels, or into intensified heat using solar collectors. Individual homes may use both passive and active forms of solar energy.

Solar panels can convert about 15% of the radiation energy they receive into electricity. Solar collectors exploit 25-35% of the energy they receive in the form of heat. If solar radiation could be exploited to a level of 100%, a surface area of 20-30 m² could provide enough energy to heat a detached house for a year.

Where solar energy is used

Solar energy systems have so far mainly been used in locations not connected to conventional power grids. Locations where solar power is used in Finland include many holiday homes, boats and ships, navigational markers, mobile communications masts, and buildings on islands or in remote areas.

But solar energy can also be exploited to provide a considerable proportion of the electricity used by a conventional home. Solar energy systems connected to the grid are becoming more common.