British businesses could save £78 million in electricity and cut CO2 emissions by 485,000 tonnes a year by choosing thin clients instead of PCs, according to researchers from Germany's Fraunhofer Institute.

That's including the extra energy cost of the servers needed for thin client computing, at a rate of 20 users per server, the researchers said, but not the environmental cost of scrapping those PCs. In their report, the researchers said that will be the subject of a further study.

"Energy consumption when in operation was up to 50 percent lower than for conventional PCs," said Dr Hartmut Pflaum, the Fraunhofer researcher. "While PCs consume about 85W on average, thin clients including their server get by with 40W to 50W. In view of climate change and the need to reduce CO2 emissions, this is an important factor."

The Fraunhofer team did their research using thin clients from Igel Technology, which is also based in Germany, and their totals assume that 10 million desktop PCs in the UK could be replaced by thin clients.

At eight hours use a day, 220 days a year, they estimated that a modern PC costs £15 a year for electricity, versus £7.30 for a set-up with thin clients and servers. More significantly, they said the electricity saving also represents a reduction in annual CO2 emissions of almost 50kg per desktop.

They said there are also energy and carbon reductions on the transportation side, as thin clients are lighter and smaller than PCs.

No one is likely to dump their PC for a saving of £8 a year, but Igel's worldwide marketing director Stephen Yeo claimed that thin clients also bring cost-of-ownership savings and need less air conditioning in the office – a factor not yet included in the Fraunhofer figures.

He suggested the decrease in pollution could be rather more valuable than the financial saving, as organisations come under increasing pressure to reduce their carbon footprint.

"There is no magic bullet to cut CO2," he said. "It's a quarter of a percent here, half a percent there. Gartner says PCs contribute half a percent to global CO2 emissions so if we can remove half of that it is very significant. We're not saying chuck out your existing equipment, but when it comes time to replace it, then this kind of data must play a part in that decision."