Researchers in Sweden report significant progress in the development of a special fluid that absorbs solar energy, holding it for months or even years and then releasing it when needed. This material can be another nail in the fossil fuels coffin, and it may yet help solve the global warming crisis.
This is thermal fuel, a molecule that can store solar energy. Light (ultraviolet radiation) rearranges the bonds between carbon atoms, hydrogen and nitrogen, and converts a compound known as norbornadiene to another compound called quadricyclane. The energy is maintained in the molecule even as the solution cools.
To extract the stored energy, the fuel is transported through a cobalt-based catalyst and the molecules then pass from quadriskylan back to Norborden while releasing the energy into the environment. If the fuel starts at room temperature (about 21 degrees celsius), it warms quickly to 84 degrees Celsius – warm enough to heat a home.
The researchers argue that even after 125 cycles of transition from storage to release of solar thermal fuel, there was no significant reduction in process efficiency. The fuel can store up to 250 watt hours of energy per kilogram. This is roughly twice the energy capacity of the Tesla Powerwall batteries.
The material is still in development and it will take some time until there is a product based on solar thermal fuels.