In order to realise the vision of a clean energy supply without nuclear power, Energy Strategy 2050 not only focusses on hydropower, but also on photovoltaics. However, the electricity grid in its current form is too rigid for a massive expansion of this decentralised and erratic energy source. This is because the power lines could be overloaded by the temporary feeding in of larger quantities of solar power into the grid. Furthermore, there are strict restrictions in place with respect to the permitted voltage in the low-voltage grid, i.e. the part of the electricity grid to which sockets and solar energy systems are connected. In many places today, it is this voltage range that limits the potential of photovoltaics.
The voltage restrictions in the low-voltage grid are related to the transformers that provide the power to the socket. The tried-and-tested transformers made from copper coils and iron cores work extremely reliably and efficiently. However, they can only transform the current in a fixed voltage ratio. Therefore, voltage specifications for the next higher grid level, namely the medium-voltage grid, also have a restrictive effect on the low-voltage grid.