Google has released data about its carbon footprint, saying it released 1.68m tonnes of carbon dioxide in 2011, not counting emission offsets.
The breakdown was 1.44m tonnes from purchased electricity to run data centres and offices; 29,500 tonnes from vehicles including Street View cars; and 208,000 tonnes from business travel, employee commuting, server manufacturing, data centre construction and fuel for offices.
Emissions per $1m revenue were 44.3 tonnes, compared to 49.3 tonnes in 2010 and 54.7 tonnes in 2009.
“Without efficiency measures in our data centers our footprint would have been about twice as big,” it said.
Its data centres use 50 per cent of the energy of ‘typical’ data centres, with the use of ‘smart’ temperature controls, using outside air or water for cooling, and measuring everything.
The “Power Usage Effectiveness”, a calculation of total energy use divided by energy need to drive the servers, is 1.14, compared to a typical industry figure of 2, the company says.
It minimises the number of times power is converted from one type of current to another, and keeps power supplies as close to the load as possible.
The company buys renewable energy, and “high quality” carbon offsets, which brings its carbon impact to zero.
100 Google searches generate 20g of CO2, as much carbon dioxide as you’d generate drying your hands with an electric dryer, ironing a shirt or to make 1.5 tablespoons of orange juice, the company says.
3 weeks of watching YouTube non stop would generate 3kg of CO2, equivalent to the emissions from one load of laundry.