It's now possible to incorporate very large amounts of variable renewable power like solar and wind into the electric grid cost-effectively without harming reliability. Here's how.
This is all very well, but the main problem with renewables is not load balancing (which is merely a technical, albeit perhaps non-trivial, issue), but rather achievable capacity. The basic fact that needs to be addressed is that although solar power could concievably meet all of our needs for as long as we will exist as a species, it cannot concievably be brought up to scale within the next 100 years. Wind, on the other hand just doesn't have the potential to do more than cover our non-transport needs. To power our demands for personal and materials transport, something much more substantial is needed, and for the next 100+ years "renewables" aren't it. There is however an option which has been available for over half a century with the capacity to be ramped up within half a century (from whenever we decide to actually go ahead with it), to provide all of our energy desires (let alone needs!). But it is politically incorrect to advocate it, so I will leave it to you to guess what it might be.