VMware is talking up the green benefits of its virtualization technology after recording a strong performance in the first quarter.

According to VMware, for every server virtualized, customers can save about 7,000 kilowatt hours, or four tons of CO2 emissions, every year. (VMware said it got the figures by using the average electricity consumption of servers and multiplying it using industry standard metrics.)

To date, approximately 6 million desktop computers and servers have been virtualized using VMware software. VMware says this has saved approximately 36.9 billion kilowatt hours of electricity each year - or more than the electricity used for heating and cooling the entire country of Denmark.

"There are two notions facing today's IT manager (when considering green IT)," said Reza Malekzadeh, senior director for products and marketing (EMEA) at VMware. "First is the green notion (i.e. being a good world citizen and saving the environment etc). The second is the reality of the wallet - which is the main driver of the business."

"Software has not previously been considered a main source of pollution," he told Techworld. "But virtualization does cut power demand, sometimes ten machines down to one. We see customers saving 80 percent of their electricity bill. There are vast savings on power, but also on cooling."

But is the IT manager buying into the green IT argument, and if they are, is it simply to be a good citizen, or more a move to save money? Well according to Malekzadeh, it is a little of both.

"With corporate charters there is pressure to be a good citizen and look after the environment," he said. "But IT managers also look at their electricity bill, and think my god look at the cost. It is the same amount of money today to run a server than to buy a server."

VMware has a green calculator on its website, which is to give IT managers an idea of the environmental impact and potential savings that can be achieved by opting for the server visualization route.

Depending on how many servers are to be virtualized, the calculator provides an environmental assessment of a virtualization move, including the equivalent of how many cars would be taken off the motorway, the equivalent trees planted, and even the equivalent annual CO2 emissions.