The scientists conclude that Germany’s transition to a new energy economy will require more than simply switching to renewables. To meet the country’s goal of generating 80% of its energy requirements from renewable sources by 2050, power grids must also be completely overhauled. It’s not just a question of creating electricity highways to transmit power over long distances: the infrastructure also needs to be adapted. In the past, it consisted of a small number of large, centralised power plants, which generated electricity that was then distributed to all users. Now there are more and more small-scale generators connected to the grid, whose wind turbines, biogas plants, and solar panels feed in varying amounts of power at different times. To assure that power supply remains stable and reliable throughout the grid under these changed conditions, radical reengineering is called for to create a decentralised network. Two aspects are of particular importance. Firstly, the restructured grid must deliver power to users at all levels dependably, from private households to industry. And secondly, the efficiency of distribution grids must exceed its present level to enable optimal utilisation of the available resources.
“Changes will have to be made on numerous levels, from the major European power grids and the distribution networks to factories, homes, and electric vehicles,” pointed out Professor Lothar Frey, director of Fraunhofer IISB. The potential for change is particularly high in homes and offices. “When you think about it, the way we do things today is crazy. Electricity is supplied by the grid at 230V and used to power electronic devices such as computers, printers, TVs, hi-fi systems and fluorescent lighting. Almost all of these devices have their own internal power supply unit (PSU) that converts 230V AC into the DC required by the device. Because these PSUs are usually made of cheap components to minimise costs, their conversion efficiency is relatively low – in other words they transform part of