Greenpeace activists scale the Apple HQ offices in Cork City and display a message 'Clean Our Cloud' to demand that the company switches from coal to renewable energy sources to power their cloud computing data center. As more people around the world use the cloud to store and share photos, videos, and documents, IT companies have to build more data centres (buildings so large they are often visible from space) that house thousands of computers and consume tremendous amounts of electricity. Some data centres use as much electricity as 250,000 European homes. The report research found that if the cloud were a country its electricity demand would currently rank 5th in the world, and is expected to triple by 2020.