Swedish scientists have developed a special liquid, called solar thermal fuel. 

Its peculiarity lies in the ability to store collected solar energy for almost two decades. Heliofuels are based on special molecules made of carbon, hydrogen and nitrogen.
Acting on these molecules by sunlight, a reaction occurs: the rebuilding of atomic bonds and an isomer is obtained at the output. Strong chemical bonds between isomers capture solar energy and are able to store it even when the temperature of the molecules drops to room temperature (about 21 degrees Celsius). When a liquid is passed through a catalyst, its molecules return to their original state, which opens up access to stored energy. In the process of completion, the stored energy in this fluid we receive in the form of heat. After a series of successful experiments, investors became interested in the development of Swedish scientists.