I find this assertion hard to believe. Merkel has been in charge of Germany's federal government for the past two decades, and throughout this period Germany's energy production from renewable sources has skyrocketed from virtually none to the leading energy source, with a share of over 60% of the nation's energy production.
In fact, if anything, Germany's production from renewables has been accelerating.
https://vizzlo.com/gallery/time-series-graph/example/power-g...
Could you provide any source that supports your assertion that the previous government has been stalling renewables?