upowerd is consuming nearly 100% of CPU.
I am currently affected by this issue on both a Lenovo Thinkpad E520 and on a desktop PC running Core i7 and Asus Z170a motherboard. Both run Kubuntu 15.10. However, I have found reports of this problem on several different distros (from Fedora to Arch to Ubuntu) going back several years.
I found these bug reports, but I don't find any workaround or solution:
FS#40444 : [upower] upowerd 0.99.0-2 eats all resources https://bugs.archlinux.org/task/40444
Bug #861642 “upowerd uses 100% cpu till killed” : Bugs : upower package : Ubuntu https://bugs.launchpad.net/ubuntu/+source/upower/+bug/861642
Bug #876279 “Upowerd excessive CPU usage” : Bugs : upower package : Ubuntu https://bugs.launchpad.net/ubuntu/+source/upower/+bug/876279