Last year, Google consumed as much energy as the American city of San Francisco. Next year, all its energy will come from wind farms and solar panels, said the online giant.

It announced on Tuesdaythat next year, it will reach 100 per cent renewable energy for its global operations in over 150 cities.

This is not to say that Google computers will consume nothing but wind and solar power.

Like almost any company, it gets power from a power company, which operates an energy grid usually supplied by a number of sources, such as hydroelectric dams, natural gas, coal and wind power.

What Google has done over the past decade is participate in deals with renewable producers, typically guaranteeing to buy the energy they produce with their wind turbines and solar cells.

Chilean company Acciona is one such producer. Google will start buying power from Acciona's El Romero in the Atacama Desert, which is Latin America's largest solar plant.