To meet the ever growing energy demands, software giant Microsoft has signed a 20-year power purchase agreement for wind energy in Texas.

Microsoft wrote in a blog that the agreement was part of its last year's commitment to become carbon neutral. It is the first time tech giant is directly purchasing electricity from a specific source.

The deal between Microsoft and RES Americas is being funded by the money that has been collected from a "Carbon fee". The fee has been raised from company's internal tax of sorts in which every department is charged for every ton of carbon produced.

Microsoft hopes this deal will be a model for other parts of its global operations.

"We're definitely looking at this as a first of a kind, but it fits into our overall desire to have more control over our energy supply," said Microsoft's director of energy strategy, Brian Janous.

RES Americas' $200 million, 55-turbine wind farm project is called Keechi. The construction will begin in December and it is expected to be fully functional by June 2015. Microsoft will be buying all 430,000 megawatt hours of energy (or enough energy to power up to 45,000 homes) produced. The amount is also about 5 to 10 percent of company's total energy consumption.

"It's a sign of the times that the price point for these renewable projects is quite attractive to them," said Rob Morgan, chief development officer for wind and solar developer RES Americas.

However the company is not alone in buying renewable power. Google Inc, Apple Inc, and other have all committed to powering their datacenters with more renewable power.

"As you can imagine when you have that much concentration of data it requires a lot of energy to keep those things running ... and those are the challenges of companies like Microsoft, Google," Janous said. "If we're going to be a consumer of energy, first let's reduce as much as we can, and then buy it."