51
On May 1, Germany ran almost entirely on renewables energy during the day
(transparency.entsoe.eu)
Some fossil-fuel-burning power plants were kept on at minimum operating levels (they're likely not designed for daily restarts) but provided less power than was used to pump water uphill in hydoelectric storage facilities.
In the beginning of the year the German grid operators had requests for over 226GW of grid connections for utility scale batteries. That is the very first step of developing a utility scale battery site, so most of that probably is not going to be built. Then again peak load in Germany was also only a bit over 75GW.