http://www.platespin.com/Products/powerrecon/calculator.aspx

With rising energy prices and growing concerns about global warming, power consumption is becoming a critical factor for data center budgets. The issue is compounded by high-density equipment such as blade servers, which need a lot of power to run, as well as significant HVAC resources. Properly planned and executed server consolidation and optimization initiatives can help organizations achieve hundreds of thousands of dollars per year in power and cooling costs – especially when servers typically run at only 5 to 10% resource utilization.

One of my colleagues higlighted this online calculator on the platespin site, it’s always interesting to see how people are calculating or showing the benefits of virtualization. It’s important to understand your server estate, to understand what it is you seek to achieve through virtualization, whether it’s abstracting the business units from the ‘tin’ the server, or being more efficient, fitting more on to fewer servers.