This is not the first time I had issues with OneDrive under a certain version of macOS. If I'm not wrong, OneDrive used to drain too much energy on Mavericks and Yosemite, but on HighSierra it was performing nicely. What did get wrong with Mojave?
I've entered the AppStore and surprisingly OneDrive appeared to be not installed. So I clicked to install and my /Applications folder ended up with two OneDrive packages, the newer one with the extension ".localized" instead of ".app". The new OneDrive installation did not recognize the existing folder, so I had to re-sync everything for preventing conflict with the former synchronization. Now it appears that the CPU usage is fixed, but Microsoft should provide a more elegant solution than keeping and old (and incompatible) OneDrive version without any warning.Try reinstalling OneDrive? I have OneDrive as well and only get 0.20-0.30 Energy Impact?