A team at London's City University has been granted a patent on a new 'green' technology that stops phone, laptop and MP3 chargers eating electricity even when nothing is connected to them.
Most consumers are aware of the issue of connected devices continuing to eat power even when batteries have fully charged, but few realise that this also applies to a small but measurable extent even if the device is then removed while the charger is left plugged into the mains
Called 'vampire' power loss, the phenomenon has largely been ignored by consumers and device makers until recently, because the amounts of energy consumed -around 0.1 watts per adaptor per day on average use cycles - were seen as being small.
With the patent now granted, the City University engineers, headed by Professor Sanowar Khan, have released full details of their solution to the issue in the form of a tiny micro-switch. This would be integrated with the phone or laptop interface cable, cutting power drain from then mains completely once the charging device has been physically removed form the other end.
According to Khan, a number of rival technologies have been tried to achieve the same aim but the team's micro-switch is the first do so without itself drawing any power.
"Sixty-five percent of UK mobile phone owners leave their chargers plugged in once a week, but the redundant adapters continue to use power," said Khan. "With around 70 million handsets in the country [2006 figures], conservative estimates suggest that six gigawatt-hours of energy - equivalent to six large power stations working for one hour each - is wasted in this way every year."
Helped by the University's the City Research & Enterprise Unit (CREU) technology transfer team, he hopes that the energy-saving reulation will require such a technology to be built into the next generation of device chargers as standard.
"I hope that a large mobile telephone company will embrace the technology," said Khan.
The issue could be how far the industry and its regulators want to go to eliminate energy wastage when bigger targets remain to be tackled. But as long as adaptors are used to charge devices from mains power, the day could arrive when even tiny savings on offer from Khan's micro-switch start to add up into a necessary economy.