© Daily MailThe computer used 1.2 megawatts to run - enough to power 1,000 homes.
The Met Office has caused a storm of controversy after it was revealed their £30million supercomputer designed to predict climate change is one of Britain's worst polluters.
The massive machine - the UK's most powerful computer with a whopping 15 million megabytes of memory - was installed in the Met Office's headquarters in Exeter, Devon.
It is capable of 1,000 billion calculations every second to feed data to 400 scientists and uses 1.2 megawatts of energy to run - enough to power more than 1,000 homes.
The machine was hailed as the 'future of weather prediction' with the ability to produce more accurate forecasts and produce climate change modelling.
However the Met Office's Headquarters has now been named as one of the worst buildings in Britain for pollution - responsible for more than 12,000 tonnes of carbon dioxide a year.
It says 75 per cent of its carbon footprint is produced by the super computer meaning the machine is officially one of the country's least green machines.
Green campaigners say it is 'ironic' that a computer designed to help stave-off climate change is responsible for such high levels of pollution.
But Met Office spokesman Barry Grommett said the computer was 'vital' to British meteorology and to help predict weather and environmental change.
He said: 'We recognise that it is big but it is also necessary. We couldn't do what we do without it.
'We would be throwing ourselves back into the dark ages of weather forecasting if we withdrew our reliance on supercomputing, it's as simple as that.'
The figures have been published by the Department of Communities and Local Government which calculated the ratings and emissions of every public building in the country.
Other buildings which appear in the list with a high carbon footprint include hospitals and large leisure centres.
The supercomputer - more powerful than 100,000 standard PCs - was installed in the Met Office's new £80 million headquarters in May.
© North NewsThe supercomputer predicted a BBQ summer, which didn't materialise. Here Max Preston, 7, paddles around flooded tents in the Lake District.
It processes information from satellite images and was hailed as capable of predicting disastrous weather events that were previously unforeseeable such as the infamous hurricane of 1987.
The IBM machine has a peak performance of 1 'Petaflop' - 1,000 billion calculations per second - which it will not reach until 2011.
It is the second time the Met Office has been criticised this year - after the machine famously helped predict a "BBQ summer" which turned out to be another wash-out.
Despite its lack of green credentials Mr Grommett said the rating process was "fundamentally flawed" and claimed its carbon footprint was more than offset by the benefits it delivers.
These included saving lives through severe weather warnings while its forecasting for the global aviation industry saved an estimated 20 million tonnes of carbon dioxide every year.
Friends of the Earth spokesman Maurice Spurway said: 'Life is full of ironies and I think this is one of those situations.'
O the irony!