Verb (used with object), : Turning off the ignition de-energizes the spark plugs.    From Dictionary.com. 

In the case of network problems, it is still standard to de-energise certain loads and disconnect distributed sources.    From Wordnik.com.  [EarthToys Alternative Energy News] Reference

He said the people of Zimbabwe were tired of the "delaying tactics used by Zanu-PF to buy time so as to de-energise the nation.    From Wordnik.com.  [News24 Top Stories] Reference