First let me say that the issues regarding renewable power in Germany have been well covered in German publications including Spiegel and newspapers. This included documented coverage of summer days where renewables provided near 100% of the power in the country, the risks of excess power taking out the grid, and the winter days where renewables & traditional utility power nearly came up short. Covered in detail in the German media is the financial fiasco where wind power is being taken off-line after it was put in place at significant expense.
There is not a "grid across the EU" being built. While there has been much fanfare from the Union for the Coordination of Transmission of Electricity (UCTE) about the
Synchronous Grid. This is all about keeping the status quo and allowing the trading of electricity, not about evolving to an advanced infrastructure. While there are interconnects using traditional overhead transmission in place across national borders to share power via electricity sales; each country effectively maintains its own national grid. Nor could the European cross-border transmission structure possibly power Germany on a low day from sunny Italy - a mere 1% of the power needs would be met from cross-border arrangements.
The issue with Germany (and Europe) gets back to the grid. Basically the entire continent (just like the U.S.) has an aging power infrastructure based on a hub & spoke architecture using traditional power plants. Adding a few more transmission power meters and few more transmission lines does not magically enable the European power infrastructure to become a "smart grid".
In order to support a "green" distributed power network which is reliable, a modern micro-grid architecture must be put in place to support the distribution of power across the local & distant areas. The modern grid must include necessary local back-up (small gas power plants) that only need to be used as lulls (in winter for instance), support large-scale net-metering (customer selling power back from the solar array on their roof), and full monitoring/routing capability of power in real-time with predictive support.
I am a huge supporter of green power. However in order for either Europe or America to properly implement it, the power grid will need to be re-designed and nearly completely re-implemented. This would be a very significant cost that power companies do not want to take on (what is the benefit to them?). It would require government mandates and money to drive this type of change to create a modern smart grid which support distributed green power.
The other thing to keep in mind is that while the Green Party in Germany may think the idea of implementing green power to support "climate change" is great -- the actual driver for Germany to make this change to renewables is to reduce their dependency on using natural gas to generate power from an unfriendly power (Russia). This drives the decision to revert to using existing coal power (to replace the removed wind power) instead of adding natural gas power plants. This, of course, will hold back any evolution to having small natural gas power plants as a local back-up to renewable power.