Mike Barrett, one of the many talented folks who works on Ops Center, recently pointed out a cool thing that you can do beginning with Ops Center 2.1: You can use it to figure out how much it costs to run your servers.

Here's how it works. Select a server from the Navigation panel in Ops Center, you can view charts of the server's power usage over different periods of time. Select the 3-week chart, and the power usage is displayed in 1-hour intervals.

Export the chart data using the button in the upper right, and find the average watts used per hour. Your power bill should tell you what they charge per kWh, so a bit of multiplication will tell you how much the server costs to run per year. It's approximate (cooling isn't included, etc.) but it's still pretty cool.