Yes we do. We store it, until we can use it. And even if we can never use it, which is very unlikely, in the core of the earth is already much, much more radioactive material, so adding a tiny bit to that, is not a big problem "as people think".

And as far as I know, there is a great deal of work to be done to upgrade the power grid, for 100% wind/solar. And much more needed storage capacity, than we currently have. And storing electricity is expensive, no matter how we do it. And unless there is really abundance of solar energy from the deserts for example, this is a real problem, since we still live in a money based economy, last time I checked.

And even if we have abundance of solar desert power ... that makes you also very dependent on it, and vulnerable to a attack on those lines for example, which is why I see small nuclear reactors even in that scenario helpful, for emergency backup.