Complementary batteries are needed
Complementary batteries are needed for an all-electric solution based on solar and wind energy.
Cheap and fast-charging batteries still need to be developed to compete seriously with fossil fuels:
-For electricity storage to compensate intermittent solar and wind;
-For energy vector for mobile devices (car, chainsaw…) not permanently connected to grid;
-For swapping a discharged battery with a full battery powering a mobile device.