If only we had developed some technology to store energy. Just think of all the possibilities, not only would we be able to store energy from solar cells to use them at night and during storms, but we could make things that work without wires! Just think, we could have tiny computers you carry in your hand, maybe you could make phone calls on them too. Or even just portable music players. Even if it was just a tape player that you could carry with you and could use stored energy, that'd be better than not having access to music anywhere. We could have cars that are able to store excess energy and be able to start themselves with electrical starters instead of needing to crank them, we could even help people that have hearts that can't keep a regular heartbeat by putting tiny electrical devices that can use stored power to help regulate their beats.50% because the other half of the day is nighttime when solar cells work really well?
God, what a fantastic world it would be. Someone should really dedicate resources to some form of energy storage device.
Or, you know, maybe it's because Germany needs a lot of energy and it takes time to transition over... Perhaps that's why it's only 50%. But let's go with the "can't store energy" argument. That makes more sense.