I can't give you those specific numbers but since around 20% of power production is covered by onshore wind right now, it's fair to say that costs aren't prohibitive. Costs for new installations have been dropping over the last years almost as much as for solar cells, which I found somewhat surprising (I thought generators were 'old technology').

The limiting factor is primarily land or, alternatively, legal: there is a lot of NIMBYism and more or less any new constructions now needs to overcome legal challenges. In some German states, the law has also become increasingly draconian, famously requiring three kilometers to the nearest dwelling in a densely-populated state where not a single spot actually fulfills that requirement.

That problem has led to a move of new production to the north of the country, which is less dense (in more than one sense) and where offshore wind is also starting to matter. This creates issues with the grid, which is increasingly required to transport the power south to where it's actually needed. Plans for new long-distance DC lines have been mired in local fights, which this package is also designed to address.