Data center energy usage has only grown by 6% in the last decade. How important have efficiency improvements been for decoupling energy from growth?

Data centers are responsible for between 1-1.5% of global electricity usage today but some scenarios project that will grow to 3-13% by 2030. How realistic is this? How efficient are servers and data centers? Will efficiency continue to improve?

If we still generate energy from non-renewable sources, how can a data center be 100% renewable? What does 100% renewables and sustainability mean for data centers and the cloud?