One drive for business will create a cache of all the files it works on as well as the user's workable directory.
This means that a 100gb onedrive for business will require 200gb of storage unless the files are deleted regularly.
The below Github link offers a .MSI file that will install a service that can clean out the cache as the files in there are no longer needed. The instructions for setting it up are included in the directory.
https://github.com/ajtowf/OfficeCacheCleaner
Download for the service installer https://github.com/ajtowf/OfficeCacheCleaner/blob/master/dist/OfficeCacheCleaner.msi
Instructions to configure the service prior to starting it https://github.com/ajtowf/OfficeCacheCleaner/blob/master/README.md