Fossil energy carriers such as oil or gas can be stored and transported. This means that they can be used at any time and any place according to demand. The existing energy system is therefore essentially demand oriented.
The situation changes when a system is to a large extent based on renewable energies, especially when wind and solar energy are involved. Wind energy and solar irradiance need to be transformed into secondary energy carriers (such as electricity) on the spot and right away. They can be stored and transported to only a limited extent. Information about the spatial and temporal availability of these sources of energy will therefore be essential for such an energy system.