Whats the hardware? How much electric energy goes into rendering a frame or a whole movie? How do they provision it (as they keep #cores fixed)? They only talk about cores, do they even use GPUs? What's running on the machines? What did they optimize lately?
So many questions! Maybe someone from Pixar's systems department is reading this :)?
Usually in crunch time if there's not enough nodes in the render farm they might rent nodes connecting them to their network for a period of time, or they might use the cloud, or they might get budget to increase their render farms.
From what I've seen the Cloud is extremely expensive for beefy machines with GPUs, but, you can see that some companies use it if you google [0] [1].
GPUs can be used for some workflows in modern studios but I would bet the majority of it is CPUs, those machines are usually running a Linux distro and the render processes (like vray / prman , etc.). Everything runs from a big NFS cluster.
[0] https://deadline.com/2020/09/weta-digital-pacts-with-amazon-...
[1] https://www.itnews.com.au/news/dreamworks-animation-steps-to...
Running 24/7 for three months, it's cheaper to buy consumer grade hardware with similar (probably better) performance. "Industrial" grade hardware (Xeon/Epyc + Quadro) it's under 12 months. We chose consumer grade bare metal.
On thing that was half surprising, half calculated in our decision was despite the operational overhead how much less stressful running your own hardware is. When we ran experimentally on the cloud, a misrender could cost us 900 euro, and sometimes we'd have to render 3 times or more for a single client. Bringing us from healthily profitable to losing money. The stress of having to get it right the first time sucked.