Microsoft pledges to be carbon neutral starting this summer

Microsoft (s MSFT) is joining a growing number of tech companies that want to do something about their growing carbon emissions due to power hungry data centers and office buildings. The software giant on Tuesday announced a plan to become carbon neutral by fiscal year 2013 (which starts this July), and said it plans to do so by putting a price on its emissions, using energy efficiency measures and buying renewable energy and carbon offsets.

Microsoft will also consider investing in renewable energy projects, the company said. It will look at signing purchase agreements to buy clean power producers, taking a stake in wind farms and methane-capture projects and building onsite clean power generation systems such as fuel cells, the company said in a white paper.

Microsoft is hardly the first tech firm to strive to be carbon neutral. Companies such as Google (s GOOG) have announced efforts to do the same and Google has been carbon neutral since the end of 2007. Last year, Google also unveiled a new website that outlines its electricity use publicly for the first time and plans to reduce its carbon footprint.

The use of carbon pricing is an interesting emphasis for Microsoft. Microsoft will put a price on its emissions based on the prevailing market prices for renewable energy and carbon offsets and each of the company’s divisions will have to use its own budget to pay for the emissions that they’ve produced. The fees will go into a central fund that Microsoft will use to buy renewable energy and carbon offsets.

“The goal is simple; to make the company’s business divisions financially responsible for the cost of their carbon emissions and drive even more focus on efficiency and environmental sustainability across Microsoft,” wrote Robert Bernard, chief environmental strategist at the company, in another blog.

The company has been using energy efficiency measures and buying carbon credits to offset its emissions for years now. It’s quite proud of being No. 3 on the Environmental Protection Agency’s annual ranking of 50 big corporations and their emission reduction efforts. Microsoft said it’s met its 2012 goal of reducing its carbon footprint by “ at least 30 percent per unit of revenue” from the 2007 levels.

Buying carbon offsets is a common strategy among companies that want to be carbon neutral. But investing in clean power generation and actually using the renewable electricity would be a more sustainable move because it cuts down on a company’s reliance on power from dirty fossil fuel sources, said Greenpeace, which has its own ranking of Internet companies and their use of clean power to run their data centers.

Greenpeace has used the list to pressure tech companies into using more clean power and share data about their energy use and carbon footprints. In its most recent report, Greenpeace praised efforts by Google, Yahoo and Facebook but was critical of Apple (s AAPL) and Amazon (s AMZN).