SAN FRANCISCO - Google is nearly doubling the amount of renewable energy feeding its massive data centres.

The long-term commitments announced Thursday cover up to 842 megawatts of power that will flow from six different wind and solar power projects scheduled to be finished within the next two years in the U.S., Chile and Sweden. Google isn't disclosing how much it expects to pay for the power.

The data centres they will provide power for enable more than one billion people to search for information, watch video clips and communicate virtually anytime they want.

Some of the renewable energy deals were signed several weeks ago, but Google timed its announcement to coincide with the U.N. conference in Paris that is exploring ways to reduce the volume of carbon emissions widely believed to be changing the Earth's climate.

"It's an opportune time to make a strong statement," said Gary Demasi, Google's director of data centre energy.

Google has now signed contracts covering two gigawatts of renewable energy, putting the company closer to its goal of having 3.6 gigawatts lined up by 2025. The two gigawatts currently under contract is enough to supply two million European homes annually, based on Google's estimate that the renewable energy projects will generate an average of about 7.4 billion kilowatt hours of power.

The company has pledged to have all of its 14 data centres worldwide running on renewable energy as part of its quest to minimize the pollution caused by the rising demand for its Internet search engine, YouTube video service, Gmail, digital maps and other services.

Google, part of a recently formed company called Alphabet Inc., still has a long way to reach that goal. By its latest estimates, renewable energy accounts for 37 per cent of the power needed to run its data centres.

Apple, Facebook and other technology companies also have been investing heavily in renewable energy in an effort to reduce the pollution caused by the popularity of their products. All of Apple's data centres, offices and stores in the U.S. already run on renewable energy, but the company is still trying to obtain cleaner power for the overseas factories that make its iPhones, iPads and other devices.

Besides signing long-term contracts with renewable energy providers, Google also has invested about $2.5 billion in companies and projects trying to produce more wind, solar and geothermal power.