Tennet TSO spent almost a billion euros last year on emergency interventions to stabilize the electric grid due to the increasing number of solar and wind turbines in Germany

Kosten für Energiewende explodieren. Alex Reichmuth. Beisler Zeitung, Jan 01 2018. https://bazonline.ch/ausland/europa/Kosten-fuer-Energiewende-explodieren/story/13230493

Google Translation: German utility company Tennet TSO spent almost a billion euros last year on emergency interventions to stabilize the grid. That's what the company announced earlier this week. The costs were thus about half higher than in 2016 (660 million euros) and around forty percent higher than in 2015 (710 million). Tennet is responsible for the electricity supply in an area that extends from Schleswig-Holstein in the north to southern Bavaria and accounts for around forty percent of Germany's area. In particular, Tennet is responsible for important north-south routes.

The reason for the increase in emergency interventions is the increasing number of solar and wind turbines in Germany. The share of renewable energy increased from 29 to 33 percent of the electricity supply last year.