We see lots of different approaches to this, depending on the datacenter operator:

1. Customer pays for power overage at an agreed to rate that is usually the same as their committed rate (but could be more). This could be based on a:
   1. Per KW consumed
   2. Per KWh consumed
   3. Per Amp consumed

2. Customer is notified that they are over their committed draw, and asked to increase their commitment. Could be:
   1. Immediately
   2. After a few months of repeated overages

3. Nothing happens (operator is not monitoring)

From: NANOG <nanog-bounces@nanog.org> On Behalf Of Alan Hannan
Sent: Thursday, September 20, 2018 7:12 PM
To: Unknown <nanog@nanog.org>
Subject: overages for power usage

What kind of typical overage costs have you seen when a customer/you use more than you've committed to?

I'm especially interested in datacenter power situations, where maybe you sign up for 5kw or 500kw and use more than that in a given month.  Is it billed at the same rate?  Is it billed at a higher rate?  What's the % increase of the higher rate versus the regular rate?

Thanks!