All of us have truly been blessed by the unlimited supply of solar energy. It may not be available all 24 hours of the day but we have equipments which can store this energy and let us use it at our convenience.
The solar lighting systems have batteries which store this energy. This energy is stored in the form of charge in chemical solutions. When required, this chemical energy can be converted to electric current by the battery.
Similarly, in solar heating appliances, we have insulator sheets or layers around the tank which prevents heat to escape from the heated up water.