Canadian Politics Today

You need to build completely redundant capacity since you can't risk blackouts if renewable output goes to zero. This doubles the capital cost of renewables if you use backups like gas. If you try to provide backups with batteries you need enough backup to deal with the statistically unlikely but possible periods where renewables could be not producing due to weather events. The cost of such batteries is too expensive to even consider.

No you do not need redundant capacity. When the sun is up the solar panel for instance simply feeds into the existing grid. When the sun goes down the existing system is still standing by.