> the German energiewende cost

The cost of the energy transition in Germany is sometimes cited as €300 billion, €500 billion, or even €1.5 trillion.

These figures are worthless because no reputable source publishes a specific figure along with the scope of the project (some aspects of the investments needed for the electricity grid are independent of the energy source) and at least a timeframe.

These figures are actually projections published by various sources, covering distant deadlines (2050, etc.) and the entire electricity system, including non-renewable energy sources (whose additional costs are often overestimated).