Saving energy - seasonal storage
In order to utilize the solar thermal energy during periods when the sun does not give sufficient contribution such as seasons with few solar hours, it is time to save energy in such a way that it can be utilized regardless of whether the sun is shining or not.
There is extensive international research in this area and within 5-10 years we will have new storage methods that will help to make you become self-sufficient with solar energy.
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Storage under the ground in combination with heat pump:
This is a method that is already in use. Examples of this are with pipes buried 1-2 meters below ground level. Heat is pumped into the pipes and the ground warms up. Later, when the sun is not shining, we use the heat pump to bring the energy back. Depending on the ground, energy can be stored for long periods and from one season to another. The same method can be used with a borehole, but it assumes that there is no drift in the ground. -
Salting / crystalization of energy:
This method is still in a research and development stage, but already about 5-10 year from now we expect the first commercial solutions on the market. Energy is captured in a salt / crystal structure and is released only by the supply of a smaller amount of energy. Thus the energy can be stored virtually unlimited. -
Phase Change Materials - PCM:
This method uses advanced molecules melting and boiling temperature to absorb or emit heat. In this way, the energy will be absorbed when we have too much of it - for example in the summer. Later, when we require energy, the energy is released again.
The IEA expects that the new storage methods will be on the market some time between 2015 and 2020. IEA has also forecasts that indicate that all new homes in the western world will be 100% self-sufficient with solar energy as early as in 2030.