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?
The great villain in the Mojave macOS is the support for the API Metal, responsible for all graphic part presented on the screen, you can achieve a few minutes or hours, reducing transparency, not ideal, but it is what I have noticed more in relation to drainage battery.
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.