At around 1.5m tonnes of carbon, the energy usage of the online giant is on a par with the United Nations

Google's carbon footprint is on a par with the United Nations, the internet giant revealed on Thursday as it published its energy usage for the first time.

Google says that it emits 1.5m tonnes of carbon annually but claims that its data centres consume 50% less energy than the industry average. The emissions are slightly higher than the country of Laos in south-east Asia and equivalent to the UN's operational footprint.

The company said that many of its "cloud-based" services for businesses, such as its popular Gmail system, can be up to 80 times less polluting than traditional alternatives, which require companies to operate their own, potentially more inefficient servers.

Google has made strides in reducing the energy use of its products and increasing the proportion of electricity it purchases from renewable sources. But the company said in a conference call that its total carbon footprint has continued to climb, reflecting a growing number of users and society's increasing reliance on online services. Google declined to reveal how much its energy use had risen since the previous year, but said that the figures would be released in the future via the Carbon Disclosure Project.

Google's energy use became the subject of scrutiny in 2009 following the publication of a story claiming that each search carried out on the website had a carbon footprint of 7g of CO 2 – around half as much as boiling the water for a cup of coffee. Google's response was to claim that this figure included many factors it was not responsible for, such as the power consumed by the user's computer, and that its share of the footprint was only 0.2g of CO 2 per search.

Today's announcement repeats the 0.2g figure and gives equivalent numbers for other Google services, such as YouTube (1g of CO 2 for each 10 minutes of viewing) and Gmail (1.2kg of CO 2 per year for the typical user). The company calculates that, in total, the typical Google user creates 1.46kg of CO 2 by consuming its various services – the equivalent of filling a deep bath or buying an imported bottle of wine. It also claims that producing and shipping a single DVD uses as much energy as watching YouTube non-stop for three days.

Last year, Facebook, came under pressure in relation to energy use following its decision to site its new data centre in Oregon and to power it with electricity largely generated from coal. However, Facebook argued that the cool climate in Oregon helped it minimise energy consumption by reducing the need for cooling.

As online activity has increased, the internet has become an increasingly significant consumer of energy, with a carbon footprint estimated to be in the hundreds of millions of tonnes – equivalent to a large industrialised country.

Google estimates that data centres account for around 1% of the world's electricity use, and that Google itself consumes around 1% of that amount.

Almost one-third of the company's electricity comes from renewable sources – a figure that is continuing to rise. The company offsets the emissions generated by the remainder of its electricity supply, along with those from its offices and transport.

Gary Cook, senior IT policy analyst for Greenpeace International, which has campaigned to make the IT sector more accountable for its energy use, said: "We've seen lots of leadership from Google on sustainability but not in terms of transparency. It's good to see them finally put their footprint data on the table, which hopefully should start a more robust debate on the energy use of online services. We need to see others doing the same."

