Every time I render or export through premiere my MacBook Pro loses battery 1% per minute

Hello

I am working on a macbook pro

memory 16 GB 2667 MHz DDR4

graphics Intel UHD Graphics 630 1536 MB

processor 2.3 GHz 8-Core Intel Core i9

Whenever I edit I work with my AC power connected.

Recently my workflow has been extremely slow becuase I am working with a lot of 4k 120 fps footage.

Because I cannot make proxies through encoder or premiere for that footage (I wrote about about that issue in another forum but it is still unresolved),  I am constantly having to re-render every time I make an adjustment. This constant rendering is overheating my laptop and as a consequence it looks like my computer is unable to hold a charge . 

I need high performance for the kind of work I'm doing,  I have all my scatch disks set to an external harddrive seperate from the project, but it seems one issue is affecting the other and I'm writing here to see if anybody has suggestions of solutions.

Thanks