Possibly.  But I'm not convinced.  I seem to
remember the biggest IBM
 3090 system drew about 250kW (I'll have to look that up too!).  I
 imagine a typical system might draw perhaps 50kW. 
That is probably for a typical installation. The actual processor is
nowhere near that value (still enough to make the utility very happy,
however). A big string of DASDs adds up very fast, especially the power
sucking IBM disks (why is that? Really big motors)?
William Donzelli
william(a)ans.net