IBM has been a leader in addressing climate change through the company's energy conservation and climate protection programs for decades. We have been tracking our energy consumption since 1973, and greenhouse gas (GHG) emissions since the late 1990s. The majority of GHG emissions associated with IBM's operations, 97 percent, come from the use of electricity and fuel in our operations. The remaining GHG emissions are associated with the use of perfluorocompounds (PFCs) and heat transfer fluids in our research activities. IBM has longstanding programs to implement energy conservation and PFC reduction initiatives and we have set and attained a series of PFC emissions reduction goals associated with our divested semiconductor operations and carbon dioxide (CO2) emissions reduction goals covering all of our operations over the past 15 years. With the divestiture of our semiconductor manufacturing operations, IBM PFC emissions are associated with research activities and are minimal.
In February 2015, IBM set two new goals to further reduce its GHG : a new renewable electricity use goal; and a third-generation GHG emissions reduction goal.
In 2016, IBM achieved and exceeded its third-generation GHG emissions reduction goal: to reduce CO2 emissions associated with our energy consumption 35 percent by year-end 2020, against base year 2005 and adjusted for acquisitions and divestitures. The goal set an objective to further reduce IBM's emission by 20 percent from 2012 to 2020, building on the 15.7 percent reduction achieved from 2005 to 2012. The achievement of this goal came four years early as IBM reduced its operational CO2 emissions by 38.1 percent against the 2005 baseline. This result was driven by a continuous decrease in energy consumption since 2011, a robust renewable electricity procurement program, and a reduction in the overall electricity emissions factor associated with IBM's grid purchased electricity.
IBM set a renewable electricity procurement goal to purchase 20 percent of its electricity consumption from renewable sources by 2020, over and above the quantity of renewable electricity provided as part of the mix of electricity that we purchase from the grid. In 2016, IBM contracted with its utility suppliers to purchase approximately 783,000 megawatt-hours of renewable electricity representing 21.5 percent of our global electricity consumption achieving the procurement goal four years early. IBM avoided 300,000 metric tons of CO2 emissions through these purchases.