The SPP region (small piece of Texas and then the heartland around Oklahoma and Kansas although there are many states) has already hit > 70% renewable penetrati

The SPP region (small piece of Texas and then the heartland around Oklahoma and Kansas although there are many states) has already hit > 70% renewable penetration during some hours of the day with very little storage, but a LOT of wind (> 20 GW). The problem is sustaining that 70% for a longer time period. Wind is intermittent, so firming it up with additional solar (also intermittent, but generally at different times) and a lot of storage would have to be the next step if you wanted a sustained > 70%. I'd guess with very high probability that this region (very geographically large), but not too many large population centers will hit 80% renewable penetration within 3 years based off of current growth. It is still a guess as to how long it will take before you'd see 80% across peak and not in the morning. Still, this has all happened in a few years.