A few months ago Salesforce committed to a goal of eventually powering its global operations entirely with renewable energy, and on Monday it took a key step in that direction by signing a 12-year agreement to back a brand-new wind farm in West Virginia.

The farm is expected to become operational in December 2016. Once it does, the electricity generated under the agreement is expected to be 125,000 megawatt hours annually, which is more than Salesforce used in its data centers during all of fiscal year 2015.

It's also equivalent to about 90 percent of its total electricity use over that time period, putting Salesforce well on the way toward that 100 percent goal.

Rather than supplying Salesforce's needs directly, the deal calls for Salesforce's purchased clean power to be delivered through a virtual power purchase agreement to the same regional electricity grid that currently powers the majority of its data-center load.

Google has also used similar agreements.

The deal is Salesforce's first major renewable-energy agreement. Salesforce recently committed to achieving net-zero greenhouse-gas emissions by 2050 as well.

Corporate buyers signed wind and solar transactions amounting to more than 3 gigawatts in 2015, up from just 1.2 gigawatts in 2014, said Herve Touati, a managing director at nonprofit Rocky Mountain Institute and head of the Business Renewables Center.

Still, with fewer than 20 corporations active in the area, Touati added, "this is just a start."