Thermal storage is for solar heat systems, and PV would use grid storage batteries. Have you heard of the new low cost grid batteries? For example, the MIT spinoff that cost a lot less than car batteries, because they don't have weight issues and by using common as dirt materials.
Ambri
What Germany is finding is that storage is not as critical as first thought - a well designed mix of renewable sources makes a predictable output, and methane digesters using farm waste and sewage can power gas turbines that burn renewable gas to meet peak demands.
Electric cars have only about 15% total losses from plug to wheel, and the motor and the controller are about half of that, so a grid battery system could be only 7-10% loss. With renewable energy, as long as you can gather enough energy - then losses do NOT really matter.